127 delete tempBlock;
128}
129
130void
131BaseCache::CacheSlavePort::setBlocked()
132{
133 assert(!blocked);
134 DPRINTF(CachePort, "Port is blocking new requests\n");
135 blocked = true;
136 // if we already scheduled a retry in this cycle, but it has not yet
137 // happened, cancel it
138 if (sendRetryEvent.scheduled()) {
139 owner.deschedule(sendRetryEvent);
140 DPRINTF(CachePort, "Port descheduled retry\n");
141 mustSendRetry = true;
142 }
143}
144
145void
146BaseCache::CacheSlavePort::clearBlocked()
147{
148 assert(blocked);
149 DPRINTF(CachePort, "Port is accepting new requests\n");
150 blocked = false;
151 if (mustSendRetry) {
152 // @TODO: need to find a better time (next cycle?)
153 owner.schedule(sendRetryEvent, curTick() + 1);
154 }
155}
156
157void
158BaseCache::CacheSlavePort::processSendRetry()
159{
160 DPRINTF(CachePort, "Port is sending retry\n");
161
162 // reset the flag and call retry
163 mustSendRetry = false;
164 sendRetryReq();
165}
166
167Addr
168BaseCache::regenerateBlkAddr(CacheBlk* blk)
169{
170 if (blk != tempBlock) {
171 return tags->regenerateBlkAddr(blk);
172 } else {
173 return tempBlock->getAddr();
174 }
175}
176
177void
178BaseCache::init()
179{
180 if (!cpuSidePort.isConnected() || !memSidePort.isConnected())
181 fatal("Cache ports on %s are not connected\n", name());
182 cpuSidePort.sendRangeChange();
183 forwardSnoops = cpuSidePort.isSnooping();
184}
185
186BaseMasterPort &
187BaseCache::getMasterPort(const std::string &if_name, PortID idx)
188{
189 if (if_name == "mem_side") {
190 return memSidePort;
191 } else {
192 return MemObject::getMasterPort(if_name, idx);
193 }
194}
195
196BaseSlavePort &
197BaseCache::getSlavePort(const std::string &if_name, PortID idx)
198{
199 if (if_name == "cpu_side") {
200 return cpuSidePort;
201 } else {
202 return MemObject::getSlavePort(if_name, idx);
203 }
204}
205
206bool
207BaseCache::inRange(Addr addr) const
208{
209 for (const auto& r : addrRanges) {
210 if (r.contains(addr)) {
211 return true;
212 }
213 }
214 return false;
215}
216
217void
218BaseCache::handleTimingReqHit(PacketPtr pkt, CacheBlk *blk, Tick request_time)
219{
220 if (pkt->needsResponse()) {
221 pkt->makeTimingResponse();
222 // @todo: Make someone pay for this
223 pkt->headerDelay = pkt->payloadDelay = 0;
224
225 // In this case we are considering request_time that takes
226 // into account the delay of the xbar, if any, and just
227 // lat, neglecting responseLatency, modelling hit latency
228 // just as lookupLatency or or the value of lat overriden
229 // by access(), that calls accessBlock() function.
230 cpuSidePort.schedTimingResp(pkt, request_time, true);
231 } else {
232 DPRINTF(Cache, "%s satisfied %s, no response needed\n", __func__,
233 pkt->print());
234
235 // queue the packet for deletion, as the sending cache is
236 // still relying on it; if the block is found in access(),
237 // CleanEvict and Writeback messages will be deleted
238 // here as well
239 pendingDelete.reset(pkt);
240 }
241}
242
243void
244BaseCache::handleTimingReqMiss(PacketPtr pkt, MSHR *mshr, CacheBlk *blk,
245 Tick forward_time, Tick request_time)
246{
247 if (mshr) {
248 /// MSHR hit
249 /// @note writebacks will be checked in getNextMSHR()
250 /// for any conflicting requests to the same block
251
252 //@todo remove hw_pf here
253
254 // Coalesce unless it was a software prefetch (see above).
255 if (pkt) {
256 assert(!pkt->isWriteback());
257 // CleanEvicts corresponding to blocks which have
258 // outstanding requests in MSHRs are simply sunk here
259 if (pkt->cmd == MemCmd::CleanEvict) {
260 pendingDelete.reset(pkt);
261 } else if (pkt->cmd == MemCmd::WriteClean) {
262 // A WriteClean should never coalesce with any
263 // outstanding cache maintenance requests.
264
265 // We use forward_time here because there is an
266 // uncached memory write, forwarded to WriteBuffer.
267 allocateWriteBuffer(pkt, forward_time);
268 } else {
269 DPRINTF(Cache, "%s coalescing MSHR for %s\n", __func__,
270 pkt->print());
271
272 assert(pkt->req->masterId() < system->maxMasters());
273 mshr_hits[pkt->cmdToIndex()][pkt->req->masterId()]++;
274
275 // We use forward_time here because it is the same
276 // considering new targets. We have multiple
277 // requests for the same address here. It
278 // specifies the latency to allocate an internal
279 // buffer and to schedule an event to the queued
280 // port and also takes into account the additional
281 // delay of the xbar.
282 mshr->allocateTarget(pkt, forward_time, order++,
283 allocOnFill(pkt->cmd));
284 if (mshr->getNumTargets() == numTarget) {
285 noTargetMSHR = mshr;
286 setBlocked(Blocked_NoTargets);
287 // need to be careful with this... if this mshr isn't
288 // ready yet (i.e. time > curTick()), we don't want to
289 // move it ahead of mshrs that are ready
290 // mshrQueue.moveToFront(mshr);
291 }
292 }
293 }
294 } else {
295 // no MSHR
296 assert(pkt->req->masterId() < system->maxMasters());
297 mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
298
299 if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean) {
300 // We use forward_time here because there is an
301 // writeback or writeclean, forwarded to WriteBuffer.
302 allocateWriteBuffer(pkt, forward_time);
303 } else {
304 if (blk && blk->isValid()) {
305 // If we have a write miss to a valid block, we
306 // need to mark the block non-readable. Otherwise
307 // if we allow reads while there's an outstanding
308 // write miss, the read could return stale data
309 // out of the cache block... a more aggressive
310 // system could detect the overlap (if any) and
311 // forward data out of the MSHRs, but we don't do
312 // that yet. Note that we do need to leave the
313 // block valid so that it stays in the cache, in
314 // case we get an upgrade response (and hence no
315 // new data) when the write miss completes.
316 // As long as CPUs do proper store/load forwarding
317 // internally, and have a sufficiently weak memory
318 // model, this is probably unnecessary, but at some
319 // point it must have seemed like we needed it...
320 assert((pkt->needsWritable() && !blk->isWritable()) ||
321 pkt->req->isCacheMaintenance());
322 blk->status &= ~BlkReadable;
323 }
324 // Here we are using forward_time, modelling the latency of
325 // a miss (outbound) just as forwardLatency, neglecting the
326 // lookupLatency component.
327 allocateMissBuffer(pkt, forward_time);
328 }
329 }
330}
331
332void
333BaseCache::recvTimingReq(PacketPtr pkt)
334{
335 // anything that is merely forwarded pays for the forward latency and
336 // the delay provided by the crossbar
337 Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
338
339 // We use lookupLatency here because it is used to specify the latency
340 // to access.
341 Cycles lat = lookupLatency;
342 CacheBlk *blk = nullptr;
343 bool satisfied = false;
344 {
345 PacketList writebacks;
346 // Note that lat is passed by reference here. The function
347 // access() calls accessBlock() which can modify lat value.
348 satisfied = access(pkt, blk, lat, writebacks);
349
350 // copy writebacks to write buffer here to ensure they logically
351 // precede anything happening below
352 doWritebacks(writebacks, forward_time);
353 }
354
355 // Here we charge the headerDelay that takes into account the latencies
356 // of the bus, if the packet comes from it.
357 // The latency charged it is just lat that is the value of lookupLatency
358 // modified by access() function, or if not just lookupLatency.
359 // In case of a hit we are neglecting response latency.
360 // In case of a miss we are neglecting forward latency.
361 Tick request_time = clockEdge(lat) + pkt->headerDelay;
362 // Here we reset the timing of the packet.
363 pkt->headerDelay = pkt->payloadDelay = 0;
364 // track time of availability of next prefetch, if any
365 Tick next_pf_time = MaxTick;
366
367 if (satisfied) {
368 // if need to notify the prefetcher we have to do it before
369 // anything else as later handleTimingReqHit might turn the
370 // packet in a response
371 if (prefetcher &&
372 (prefetchOnAccess || (blk && blk->wasPrefetched()))) {
373 if (blk)
374 blk->status &= ~BlkHWPrefetched;
375
376 // Don't notify on SWPrefetch
377 if (!pkt->cmd.isSWPrefetch()) {
378 assert(!pkt->req->isCacheMaintenance());
379 next_pf_time = prefetcher->notify(pkt);
380 }
381 }
382
383 handleTimingReqHit(pkt, blk, request_time);
384 } else {
385 handleTimingReqMiss(pkt, blk, forward_time, request_time);
386
387 // We should call the prefetcher reguardless if the request is
388 // satisfied or not, reguardless if the request is in the MSHR
389 // or not. The request could be a ReadReq hit, but still not
390 // satisfied (potentially because of a prior write to the same
391 // cache line. So, even when not satisfied, there is an MSHR
392 // already allocated for this, we need to let the prefetcher
393 // know about the request
394
395 // Don't notify prefetcher on SWPrefetch or cache maintenance
396 // operations
397 if (prefetcher && pkt &&
398 !pkt->cmd.isSWPrefetch() &&
399 !pkt->req->isCacheMaintenance()) {
400 next_pf_time = prefetcher->notify(pkt);
401 }
402 }
403
404 if (next_pf_time != MaxTick) {
405 schedMemSideSendEvent(next_pf_time);
406 }
407}
408
409void
410BaseCache::handleUncacheableWriteResp(PacketPtr pkt)
411{
412 Tick completion_time = clockEdge(responseLatency) +
413 pkt->headerDelay + pkt->payloadDelay;
414
415 // Reset the bus additional time as it is now accounted for
416 pkt->headerDelay = pkt->payloadDelay = 0;
417
418 cpuSidePort.schedTimingResp(pkt, completion_time, true);
419}
420
421void
422BaseCache::recvTimingResp(PacketPtr pkt)
423{
424 assert(pkt->isResponse());
425
426 // all header delay should be paid for by the crossbar, unless
427 // this is a prefetch response from above
428 panic_if(pkt->headerDelay != 0 && pkt->cmd != MemCmd::HardPFResp,
429 "%s saw a non-zero packet delay\n", name());
430
431 const bool is_error = pkt->isError();
432
433 if (is_error) {
434 DPRINTF(Cache, "%s: Cache received %s with error\n", __func__,
435 pkt->print());
436 }
437
438 DPRINTF(Cache, "%s: Handling response %s\n", __func__,
439 pkt->print());
440
441 // if this is a write, we should be looking at an uncacheable
442 // write
443 if (pkt->isWrite()) {
444 assert(pkt->req->isUncacheable());
445 handleUncacheableWriteResp(pkt);
446 return;
447 }
448
449 // we have dealt with any (uncacheable) writes above, from here on
450 // we know we are dealing with an MSHR due to a miss or a prefetch
451 MSHR *mshr = dynamic_cast<MSHR*>(pkt->popSenderState());
452 assert(mshr);
453
454 if (mshr == noTargetMSHR) {
455 // we always clear at least one target
456 clearBlocked(Blocked_NoTargets);
457 noTargetMSHR = nullptr;
458 }
459
460 // Initial target is used just for stats
461 MSHR::Target *initial_tgt = mshr->getTarget();
462 int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
463 Tick miss_latency = curTick() - initial_tgt->recvTime;
464
465 if (pkt->req->isUncacheable()) {
466 assert(pkt->req->masterId() < system->maxMasters());
467 mshr_uncacheable_lat[stats_cmd_idx][pkt->req->masterId()] +=
468 miss_latency;
469 } else {
470 assert(pkt->req->masterId() < system->maxMasters());
471 mshr_miss_latency[stats_cmd_idx][pkt->req->masterId()] +=
472 miss_latency;
473 }
474
475 PacketList writebacks;
476
477 bool is_fill = !mshr->isForward &&
478 (pkt->isRead() || pkt->cmd == MemCmd::UpgradeResp);
479
480 CacheBlk *blk = tags->findBlock(pkt->getAddr(), pkt->isSecure());
481
482 if (is_fill && !is_error) {
483 DPRINTF(Cache, "Block for addr %#llx being updated in Cache\n",
484 pkt->getAddr());
485
486 blk = handleFill(pkt, blk, writebacks, mshr->allocOnFill());
487 assert(blk != nullptr);
488 }
489
490 if (blk && blk->isValid() && pkt->isClean() && !pkt->isInvalidate()) {
491 // The block was marked not readable while there was a pending
492 // cache maintenance operation, restore its flag.
493 blk->status |= BlkReadable;
494
495 // This was a cache clean operation (without invalidate)
496 // and we have a copy of the block already. Since there
497 // is no invalidation, we can promote targets that don't
498 // require a writable copy
499 mshr->promoteReadable();
500 }
501
502 if (blk && blk->isWritable() && !pkt->req->isCacheInvalidate()) {
503 // If at this point the referenced block is writable and the
504 // response is not a cache invalidate, we promote targets that
505 // were deferred as we couldn't guarrantee a writable copy
506 mshr->promoteWritable();
507 }
508
509 serviceMSHRTargets(mshr, pkt, blk, writebacks);
510
511 if (mshr->promoteDeferredTargets()) {
512 // avoid later read getting stale data while write miss is
513 // outstanding.. see comment in timingAccess()
514 if (blk) {
515 blk->status &= ~BlkReadable;
516 }
517 mshrQueue.markPending(mshr);
518 schedMemSideSendEvent(clockEdge() + pkt->payloadDelay);
519 } else {
520 // while we deallocate an mshr from the queue we still have to
521 // check the isFull condition before and after as we might
522 // have been using the reserved entries already
523 const bool was_full = mshrQueue.isFull();
524 mshrQueue.deallocate(mshr);
525 if (was_full && !mshrQueue.isFull()) {
526 clearBlocked(Blocked_NoMSHRs);
527 }
528
529 // Request the bus for a prefetch if this deallocation freed enough
530 // MSHRs for a prefetch to take place
531 if (prefetcher && mshrQueue.canPrefetch()) {
532 Tick next_pf_time = std::max(prefetcher->nextPrefetchReadyTime(),
533 clockEdge());
534 if (next_pf_time != MaxTick)
535 schedMemSideSendEvent(next_pf_time);
536 }
537 }
538
539 // if we used temp block, check to see if its valid and then clear it out
540 if (blk == tempBlock && tempBlock->isValid()) {
541 evictBlock(blk, writebacks);
542 }
543
544 const Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
545 // copy writebacks to write buffer
546 doWritebacks(writebacks, forward_time);
547
548 DPRINTF(CacheVerbose, "%s: Leaving with %s\n", __func__, pkt->print());
549 delete pkt;
550}
551
552
553Tick
554BaseCache::recvAtomic(PacketPtr pkt)
555{
556 // We are in atomic mode so we pay just for lookupLatency here.
557 Cycles lat = lookupLatency;
558
559 // follow the same flow as in recvTimingReq, and check if a cache
560 // above us is responding
561 if (pkt->cacheResponding() && !pkt->isClean()) {
562 assert(!pkt->req->isCacheInvalidate());
563 DPRINTF(Cache, "Cache above responding to %s: not responding\n",
564 pkt->print());
565
566 // if a cache is responding, and it had the line in Owned
567 // rather than Modified state, we need to invalidate any
568 // copies that are not on the same path to memory
569 assert(pkt->needsWritable() && !pkt->responderHadWritable());
570 lat += ticksToCycles(memSidePort.sendAtomic(pkt));
571
572 return lat * clockPeriod();
573 }
574
575 // should assert here that there are no outstanding MSHRs or
576 // writebacks... that would mean that someone used an atomic
577 // access in timing mode
578
579 CacheBlk *blk = nullptr;
580 PacketList writebacks;
581 bool satisfied = access(pkt, blk, lat, writebacks);
582
583 if (pkt->isClean() && blk && blk->isDirty()) {
584 // A cache clean opearation is looking for a dirty
585 // block. If a dirty block is encountered a WriteClean
586 // will update any copies to the path to the memory
587 // until the point of reference.
588 DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
589 __func__, pkt->print(), blk->print());
590 PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(), pkt->id);
591 writebacks.push_back(wb_pkt);
592 pkt->setSatisfied();
593 }
594
595 // handle writebacks resulting from the access here to ensure they
596 // logically precede anything happening below
597 doWritebacksAtomic(writebacks);
598 assert(writebacks.empty());
599
600 if (!satisfied) {
601 lat += handleAtomicReqMiss(pkt, blk, writebacks);
602 }
603
604 // Note that we don't invoke the prefetcher at all in atomic mode.
605 // It's not clear how to do it properly, particularly for
606 // prefetchers that aggressively generate prefetch candidates and
607 // rely on bandwidth contention to throttle them; these will tend
608 // to pollute the cache in atomic mode since there is no bandwidth
609 // contention. If we ever do want to enable prefetching in atomic
610 // mode, though, this is the place to do it... see timingAccess()
611 // for an example (though we'd want to issue the prefetch(es)
612 // immediately rather than calling requestMemSideBus() as we do
613 // there).
614
615 // do any writebacks resulting from the response handling
616 doWritebacksAtomic(writebacks);
617
618 // if we used temp block, check to see if its valid and if so
619 // clear it out, but only do so after the call to recvAtomic is
620 // finished so that any downstream observers (such as a snoop
621 // filter), first see the fill, and only then see the eviction
622 if (blk == tempBlock && tempBlock->isValid()) {
623 // the atomic CPU calls recvAtomic for fetch and load/store
624 // sequentuially, and we may already have a tempBlock
625 // writeback from the fetch that we have not yet sent
626 if (tempBlockWriteback) {
627 // if that is the case, write the prevoius one back, and
628 // do not schedule any new event
629 writebackTempBlockAtomic();
630 } else {
631 // the writeback/clean eviction happens after the call to
632 // recvAtomic has finished (but before any successive
633 // calls), so that the response handling from the fill is
634 // allowed to happen first
635 schedule(writebackTempBlockAtomicEvent, curTick());
636 }
637
638 tempBlockWriteback = evictBlock(blk);
639 }
640
641 if (pkt->needsResponse()) {
642 pkt->makeAtomicResponse();
643 }
644
645 return lat * clockPeriod();
646}
647
648void
649BaseCache::functionalAccess(PacketPtr pkt, bool from_cpu_side)
650{
651 Addr blk_addr = pkt->getBlockAddr(blkSize);
652 bool is_secure = pkt->isSecure();
653 CacheBlk *blk = tags->findBlock(pkt->getAddr(), is_secure);
654 MSHR *mshr = mshrQueue.findMatch(blk_addr, is_secure);
655
656 pkt->pushLabel(name());
657
658 CacheBlkPrintWrapper cbpw(blk);
659
660 // Note that just because an L2/L3 has valid data doesn't mean an
661 // L1 doesn't have a more up-to-date modified copy that still
662 // needs to be found. As a result we always update the request if
663 // we have it, but only declare it satisfied if we are the owner.
664
665 // see if we have data at all (owned or otherwise)
666 bool have_data = blk && blk->isValid()
667 && pkt->trySatisfyFunctional(&cbpw, blk_addr, is_secure, blkSize,
668 blk->data);
669
670 // data we have is dirty if marked as such or if we have an
671 // in-service MSHR that is pending a modified line
672 bool have_dirty =
673 have_data && (blk->isDirty() ||
674 (mshr && mshr->inService && mshr->isPendingModified()));
675
676 bool done = have_dirty ||
677 cpuSidePort.trySatisfyFunctional(pkt) ||
678 mshrQueue.trySatisfyFunctional(pkt, blk_addr) ||
679 writeBuffer.trySatisfyFunctional(pkt, blk_addr) ||
680 memSidePort.trySatisfyFunctional(pkt);
681
682 DPRINTF(CacheVerbose, "%s: %s %s%s%s\n", __func__, pkt->print(),
683 (blk && blk->isValid()) ? "valid " : "",
684 have_data ? "data " : "", done ? "done " : "");
685
686 // We're leaving the cache, so pop cache->name() label
687 pkt->popLabel();
688
689 if (done) {
690 pkt->makeResponse();
691 } else {
692 // if it came as a request from the CPU side then make sure it
693 // continues towards the memory side
694 if (from_cpu_side) {
695 memSidePort.sendFunctional(pkt);
696 } else if (cpuSidePort.isSnooping()) {
697 // if it came from the memory side, it must be a snoop request
698 // and we should only forward it if we are forwarding snoops
699 cpuSidePort.sendFunctionalSnoop(pkt);
700 }
701 }
702}
703
704
705void
706BaseCache::cmpAndSwap(CacheBlk *blk, PacketPtr pkt)
707{
708 assert(pkt->isRequest());
709
710 uint64_t overwrite_val;
711 bool overwrite_mem;
712 uint64_t condition_val64;
713 uint32_t condition_val32;
714
715 int offset = pkt->getOffset(blkSize);
716 uint8_t *blk_data = blk->data + offset;
717
718 assert(sizeof(uint64_t) >= pkt->getSize());
719
720 overwrite_mem = true;
721 // keep a copy of our possible write value, and copy what is at the
722 // memory address into the packet
723 pkt->writeData((uint8_t *)&overwrite_val);
724 pkt->setData(blk_data);
725
726 if (pkt->req->isCondSwap()) {
727 if (pkt->getSize() == sizeof(uint64_t)) {
728 condition_val64 = pkt->req->getExtraData();
729 overwrite_mem = !std::memcmp(&condition_val64, blk_data,
730 sizeof(uint64_t));
731 } else if (pkt->getSize() == sizeof(uint32_t)) {
732 condition_val32 = (uint32_t)pkt->req->getExtraData();
733 overwrite_mem = !std::memcmp(&condition_val32, blk_data,
734 sizeof(uint32_t));
735 } else
736 panic("Invalid size for conditional read/write\n");
737 }
738
739 if (overwrite_mem) {
740 std::memcpy(blk_data, &overwrite_val, pkt->getSize());
741 blk->status |= BlkDirty;
742 }
743}
744
745QueueEntry*
746BaseCache::getNextQueueEntry()
747{
748 // Check both MSHR queue and write buffer for potential requests,
749 // note that null does not mean there is no request, it could
750 // simply be that it is not ready
751 MSHR *miss_mshr = mshrQueue.getNext();
752 WriteQueueEntry *wq_entry = writeBuffer.getNext();
753
754 // If we got a write buffer request ready, first priority is a
755 // full write buffer, otherwise we favour the miss requests
756 if (wq_entry && (writeBuffer.isFull() || !miss_mshr)) {
757 // need to search MSHR queue for conflicting earlier miss.
758 MSHR *conflict_mshr =
759 mshrQueue.findPending(wq_entry->blkAddr,
760 wq_entry->isSecure);
761
762 if (conflict_mshr && conflict_mshr->order < wq_entry->order) {
763 // Service misses in order until conflict is cleared.
764 return conflict_mshr;
765
766 // @todo Note that we ignore the ready time of the conflict here
767 }
768
769 // No conflicts; issue write
770 return wq_entry;
771 } else if (miss_mshr) {
772 // need to check for conflicting earlier writeback
773 WriteQueueEntry *conflict_mshr =
774 writeBuffer.findPending(miss_mshr->blkAddr,
775 miss_mshr->isSecure);
776 if (conflict_mshr) {
777 // not sure why we don't check order here... it was in the
778 // original code but commented out.
779
780 // The only way this happens is if we are
781 // doing a write and we didn't have permissions
782 // then subsequently saw a writeback (owned got evicted)
783 // We need to make sure to perform the writeback first
784 // To preserve the dirty data, then we can issue the write
785
786 // should we return wq_entry here instead? I.e. do we
787 // have to flush writes in order? I don't think so... not
788 // for Alpha anyway. Maybe for x86?
789 return conflict_mshr;
790
791 // @todo Note that we ignore the ready time of the conflict here
792 }
793
794 // No conflicts; issue read
795 return miss_mshr;
796 }
797
798 // fall through... no pending requests. Try a prefetch.
799 assert(!miss_mshr && !wq_entry);
800 if (prefetcher && mshrQueue.canPrefetch()) {
801 // If we have a miss queue slot, we can try a prefetch
802 PacketPtr pkt = prefetcher->getPacket();
803 if (pkt) {
804 Addr pf_addr = pkt->getBlockAddr(blkSize);
805 if (!tags->findBlock(pf_addr, pkt->isSecure()) &&
806 !mshrQueue.findMatch(pf_addr, pkt->isSecure()) &&
807 !writeBuffer.findMatch(pf_addr, pkt->isSecure())) {
808 // Update statistic on number of prefetches issued
809 // (hwpf_mshr_misses)
810 assert(pkt->req->masterId() < system->maxMasters());
811 mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
812
813 // allocate an MSHR and return it, note
814 // that we send the packet straight away, so do not
815 // schedule the send
816 return allocateMissBuffer(pkt, curTick(), false);
817 } else {
818 // free the request and packet
819 delete pkt;
820 }
821 }
822 }
823
824 return nullptr;
825}
826
827void
828BaseCache::satisfyRequest(PacketPtr pkt, CacheBlk *blk, bool, bool)
829{
830 assert(pkt->isRequest());
831
832 assert(blk && blk->isValid());
833 // Occasionally this is not true... if we are a lower-level cache
834 // satisfying a string of Read and ReadEx requests from
835 // upper-level caches, a Read will mark the block as shared but we
836 // can satisfy a following ReadEx anyway since we can rely on the
837 // Read requester(s) to have buffered the ReadEx snoop and to
838 // invalidate their blocks after receiving them.
839 // assert(!pkt->needsWritable() || blk->isWritable());
840 assert(pkt->getOffset(blkSize) + pkt->getSize() <= blkSize);
841
842 // Check RMW operations first since both isRead() and
843 // isWrite() will be true for them
844 if (pkt->cmd == MemCmd::SwapReq) {
845 if (pkt->isAtomicOp()) {
846 // extract data from cache and save it into the data field in
847 // the packet as a return value from this atomic op
848
849 int offset = tags->extractBlkOffset(pkt->getAddr());
850 uint8_t *blk_data = blk->data + offset;
851 std::memcpy(pkt->getPtr<uint8_t>(), blk_data, pkt->getSize());
852
853 // execute AMO operation
854 (*(pkt->getAtomicOp()))(blk_data);
855
856 // set block status to dirty
857 blk->status |= BlkDirty;
858 } else {
859 cmpAndSwap(blk, pkt);
860 }
861 } else if (pkt->isWrite()) {
862 // we have the block in a writable state and can go ahead,
863 // note that the line may be also be considered writable in
864 // downstream caches along the path to memory, but always
865 // Exclusive, and never Modified
866 assert(blk->isWritable());
867 // Write or WriteLine at the first cache with block in writable state
868 if (blk->checkWrite(pkt)) {
869 pkt->writeDataToBlock(blk->data, blkSize);
870 }
871 // Always mark the line as dirty (and thus transition to the
872 // Modified state) even if we are a failed StoreCond so we
873 // supply data to any snoops that have appended themselves to
874 // this cache before knowing the store will fail.
875 blk->status |= BlkDirty;
876 DPRINTF(CacheVerbose, "%s for %s (write)\n", __func__, pkt->print());
877 } else if (pkt->isRead()) {
878 if (pkt->isLLSC()) {
879 blk->trackLoadLocked(pkt);
880 }
881
882 // all read responses have a data payload
883 assert(pkt->hasRespData());
884 pkt->setDataFromBlock(blk->data, blkSize);
885 } else if (pkt->isUpgrade()) {
886 // sanity check
887 assert(!pkt->hasSharers());
888
889 if (blk->isDirty()) {
890 // we were in the Owned state, and a cache above us that
891 // has the line in Shared state needs to be made aware
892 // that the data it already has is in fact dirty
893 pkt->setCacheResponding();
894 blk->status &= ~BlkDirty;
895 }
896 } else if (pkt->isClean()) {
897 blk->status &= ~BlkDirty;
898 } else {
899 assert(pkt->isInvalidate());
900 invalidateBlock(blk);
901 DPRINTF(CacheVerbose, "%s for %s (invalidation)\n", __func__,
902 pkt->print());
903 }
904}
905
906/////////////////////////////////////////////////////
907//
908// Access path: requests coming in from the CPU side
909//
910/////////////////////////////////////////////////////
911
912bool
913BaseCache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
914 PacketList &writebacks)
915{
916 // sanity check
917 assert(pkt->isRequest());
918
919 chatty_assert(!(isReadOnly && pkt->isWrite()),
920 "Should never see a write in a read-only cache %s\n",
921 name());
922
923 // Here lat is the value passed as parameter to accessBlock() function
924 // that can modify its value.
925 blk = tags->accessBlock(pkt->getAddr(), pkt->isSecure(), lat);
926
927 DPRINTF(Cache, "%s for %s %s\n", __func__, pkt->print(),
928 blk ? "hit " + blk->print() : "miss");
929
930 if (pkt->req->isCacheMaintenance()) {
931 // A cache maintenance operation is always forwarded to the
932 // memory below even if the block is found in dirty state.
933
934 // We defer any changes to the state of the block until we
935 // create and mark as in service the mshr for the downstream
936 // packet.
937 return false;
938 }
939
940 if (pkt->isEviction()) {
941 // We check for presence of block in above caches before issuing
942 // Writeback or CleanEvict to write buffer. Therefore the only
943 // possible cases can be of a CleanEvict packet coming from above
944 // encountering a Writeback generated in this cache peer cache and
945 // waiting in the write buffer. Cases of upper level peer caches
946 // generating CleanEvict and Writeback or simply CleanEvict and
947 // CleanEvict almost simultaneously will be caught by snoops sent out
948 // by crossbar.
949 WriteQueueEntry *wb_entry = writeBuffer.findMatch(pkt->getAddr(),
950 pkt->isSecure());
951 if (wb_entry) {
952 assert(wb_entry->getNumTargets() == 1);
953 PacketPtr wbPkt = wb_entry->getTarget()->pkt;
954 assert(wbPkt->isWriteback());
955
956 if (pkt->isCleanEviction()) {
957 // The CleanEvict and WritebackClean snoops into other
958 // peer caches of the same level while traversing the
959 // crossbar. If a copy of the block is found, the
960 // packet is deleted in the crossbar. Hence, none of
961 // the other upper level caches connected to this
962 // cache have the block, so we can clear the
963 // BLOCK_CACHED flag in the Writeback if set and
964 // discard the CleanEvict by returning true.
965 wbPkt->clearBlockCached();
966 return true;
967 } else {
968 assert(pkt->cmd == MemCmd::WritebackDirty);
969 // Dirty writeback from above trumps our clean
970 // writeback... discard here
971 // Note: markInService will remove entry from writeback buffer.
972 markInService(wb_entry);
973 delete wbPkt;
974 }
975 }
976 }
977
978 // Writeback handling is special case. We can write the block into
979 // the cache without having a writeable copy (or any copy at all).
980 if (pkt->isWriteback()) {
981 assert(blkSize == pkt->getSize());
982
983 // we could get a clean writeback while we are having
984 // outstanding accesses to a block, do the simple thing for
985 // now and drop the clean writeback so that we do not upset
986 // any ordering/decisions about ownership already taken
987 if (pkt->cmd == MemCmd::WritebackClean &&
988 mshrQueue.findMatch(pkt->getAddr(), pkt->isSecure())) {
989 DPRINTF(Cache, "Clean writeback %#llx to block with MSHR, "
990 "dropping\n", pkt->getAddr());
991 return true;
992 }
993
994 if (!blk) {
995 // need to do a replacement
996 blk = allocateBlock(pkt, writebacks);
997 if (!blk) {
998 // no replaceable block available: give up, fwd to next level.
999 incMissCount(pkt);
1000 return false;
1001 }
1002
1003 blk->status |= (BlkValid | BlkReadable);
1004 }
1005 // only mark the block dirty if we got a writeback command,
1006 // and leave it as is for a clean writeback
1007 if (pkt->cmd == MemCmd::WritebackDirty) {
1008 // TODO: the coherent cache can assert(!blk->isDirty());
1009 blk->status |= BlkDirty;
1010 }
1011 // if the packet does not have sharers, it is passing
1012 // writable, and we got the writeback in Modified or Exclusive
1013 // state, if not we are in the Owned or Shared state
1014 if (!pkt->hasSharers()) {
1015 blk->status |= BlkWritable;
1016 }
1017 // nothing else to do; writeback doesn't expect response
1018 assert(!pkt->needsResponse());
1019 pkt->writeDataToBlock(blk->data, blkSize);
1020 DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1021 incHitCount(pkt);
1022 // populate the time when the block will be ready to access.
1023 blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1024 pkt->payloadDelay;
1025 return true;
1026 } else if (pkt->cmd == MemCmd::CleanEvict) {
1027 if (blk) {
1028 // Found the block in the tags, need to stop CleanEvict from
1029 // propagating further down the hierarchy. Returning true will
1030 // treat the CleanEvict like a satisfied write request and delete
1031 // it.
1032 return true;
1033 }
1034 // We didn't find the block here, propagate the CleanEvict further
1035 // down the memory hierarchy. Returning false will treat the CleanEvict
1036 // like a Writeback which could not find a replaceable block so has to
1037 // go to next level.
1038 return false;
1039 } else if (pkt->cmd == MemCmd::WriteClean) {
1040 // WriteClean handling is a special case. We can allocate a
1041 // block directly if it doesn't exist and we can update the
1042 // block immediately. The WriteClean transfers the ownership
1043 // of the block as well.
1044 assert(blkSize == pkt->getSize());
1045
1046 if (!blk) {
1047 if (pkt->writeThrough()) {
1048 // if this is a write through packet, we don't try to
1049 // allocate if the block is not present
1050 return false;
1051 } else {
1052 // a writeback that misses needs to allocate a new block
1053 blk = allocateBlock(pkt, writebacks);
1054 if (!blk) {
1055 // no replaceable block available: give up, fwd to
1056 // next level.
1057 incMissCount(pkt);
1058 return false;
1059 }
1060
1061 blk->status |= (BlkValid | BlkReadable);
1062 }
1063 }
1064
1065 // at this point either this is a writeback or a write-through
1066 // write clean operation and the block is already in this
1067 // cache, we need to update the data and the block flags
1068 assert(blk);
1069 // TODO: the coherent cache can assert(!blk->isDirty());
1070 if (!pkt->writeThrough()) {
1071 blk->status |= BlkDirty;
1072 }
1073 // nothing else to do; writeback doesn't expect response
1074 assert(!pkt->needsResponse());
1075 pkt->writeDataToBlock(blk->data, blkSize);
1076 DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1077
1078 incHitCount(pkt);
1079 // populate the time when the block will be ready to access.
1080 blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1081 pkt->payloadDelay;
1082 // if this a write-through packet it will be sent to cache
1083 // below
1084 return !pkt->writeThrough();
1085 } else if (blk && (pkt->needsWritable() ? blk->isWritable() :
1086 blk->isReadable())) {
1087 // OK to satisfy access
1088 incHitCount(pkt);
1089 satisfyRequest(pkt, blk);
1090 maintainClusivity(pkt->fromCache(), blk);
1091
1092 return true;
1093 }
1094
1095 // Can't satisfy access normally... either no block (blk == nullptr)
1096 // or have block but need writable
1097
1098 incMissCount(pkt);
1099
1100 if (!blk && pkt->isLLSC() && pkt->isWrite()) {
1101 // complete miss on store conditional... just give up now
1102 pkt->req->setExtraData(0);
1103 return true;
1104 }
1105
1106 return false;
1107}
1108
1109void
1110BaseCache::maintainClusivity(bool from_cache, CacheBlk *blk)
1111{
1112 if (from_cache && blk && blk->isValid() && !blk->isDirty() &&
1113 clusivity == Enums::mostly_excl) {
1114 // if we have responded to a cache, and our block is still
1115 // valid, but not dirty, and this cache is mostly exclusive
1116 // with respect to the cache above, drop the block
1117 invalidateBlock(blk);
1118 }
1119}
1120
1121CacheBlk*
1122BaseCache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks,
1123 bool allocate)
1124{
1125 assert(pkt->isResponse() || pkt->cmd == MemCmd::WriteLineReq);
1126 Addr addr = pkt->getAddr();
1127 bool is_secure = pkt->isSecure();
1128#if TRACING_ON
1129 CacheBlk::State old_state = blk ? blk->status : 0;
1130#endif
1131
1132 // When handling a fill, we should have no writes to this line.
1133 assert(addr == pkt->getBlockAddr(blkSize));
1134 assert(!writeBuffer.findMatch(addr, is_secure));
1135
1136 if (!blk) {
1137 // better have read new data...
1138 assert(pkt->hasData());
1139
1140 // only read responses and write-line requests have data;
1141 // note that we don't write the data here for write-line - that
1142 // happens in the subsequent call to satisfyRequest
1143 assert(pkt->isRead() || pkt->cmd == MemCmd::WriteLineReq);
1144
1145 // need to do a replacement if allocating, otherwise we stick
1146 // with the temporary storage
1147 blk = allocate ? allocateBlock(pkt, writebacks) : nullptr;
1148
1149 if (!blk) {
1150 // No replaceable block or a mostly exclusive
1151 // cache... just use temporary storage to complete the
1152 // current request and then get rid of it
1153 assert(!tempBlock->isValid());
1154 blk = tempBlock;
1155 tempBlock->insert(addr, is_secure);
1156 DPRINTF(Cache, "using temp block for %#llx (%s)\n", addr,
1157 is_secure ? "s" : "ns");
1158 }
1159
1160 // we should never be overwriting a valid block
1161 assert(!blk->isValid());
1162 } else {
1163 // existing block... probably an upgrade
1164 assert(regenerateBlkAddr(blk) == addr);
1165 assert(blk->isSecure() == is_secure);
1166 // either we're getting new data or the block should already be valid
1167 assert(pkt->hasData() || blk->isValid());
1168 // don't clear block status... if block is already dirty we
1169 // don't want to lose that
1170 }
1171
1172 blk->status |= BlkValid | BlkReadable;
1173
1174 // sanity check for whole-line writes, which should always be
1175 // marked as writable as part of the fill, and then later marked
1176 // dirty as part of satisfyRequest
1177 if (pkt->cmd == MemCmd::WriteLineReq) {
1178 assert(!pkt->hasSharers());
1179 }
1180
1181 // here we deal with setting the appropriate state of the line,
1182 // and we start by looking at the hasSharers flag, and ignore the
1183 // cacheResponding flag (normally signalling dirty data) if the
1184 // packet has sharers, thus the line is never allocated as Owned
1185 // (dirty but not writable), and always ends up being either
1186 // Shared, Exclusive or Modified, see Packet::setCacheResponding
1187 // for more details
1188 if (!pkt->hasSharers()) {
1189 // we could get a writable line from memory (rather than a
1190 // cache) even in a read-only cache, note that we set this bit
1191 // even for a read-only cache, possibly revisit this decision
1192 blk->status |= BlkWritable;
1193
1194 // check if we got this via cache-to-cache transfer (i.e., from a
1195 // cache that had the block in Modified or Owned state)
1196 if (pkt->cacheResponding()) {
1197 // we got the block in Modified state, and invalidated the
1198 // owners copy
1199 blk->status |= BlkDirty;
1200
1201 chatty_assert(!isReadOnly, "Should never see dirty snoop response "
1202 "in read-only cache %s\n", name());
1203 }
1204 }
1205
1206 DPRINTF(Cache, "Block addr %#llx (%s) moving from state %x to %s\n",
1207 addr, is_secure ? "s" : "ns", old_state, blk->print());
1208
1209 // if we got new data, copy it in (checking for a read response
1210 // and a response that has data is the same in the end)
1211 if (pkt->isRead()) {
1212 // sanity checks
1213 assert(pkt->hasData());
1214 assert(pkt->getSize() == blkSize);
1215
1216 pkt->writeDataToBlock(blk->data, blkSize);
1217 }
1218 // We pay for fillLatency here.
1219 blk->whenReady = clockEdge() + fillLatency * clockPeriod() +
1220 pkt->payloadDelay;
1221
1222 return blk;
1223}
1224
1225CacheBlk*
1226BaseCache::allocateBlock(const PacketPtr pkt, PacketList &writebacks)
1227{
1228 // Get address
1229 const Addr addr = pkt->getAddr();
1230
1231 // Get secure bit
1232 const bool is_secure = pkt->isSecure();
1233
1234 // Find replacement victim
1235 std::vector<CacheBlk*> evict_blks;
1236 CacheBlk *victim = tags->findVictim(addr, is_secure, evict_blks);
1237
1238 // It is valid to return nullptr if there is no victim
1239 if (!victim)
1240 return nullptr;
1241
1242 // Check for transient state allocations. If any of the entries listed
1243 // for eviction has a transient state, the allocation fails
1244 for (const auto& blk : evict_blks) {
1245 if (blk->isValid()) {
1246 Addr repl_addr = regenerateBlkAddr(blk);
1247 MSHR *repl_mshr = mshrQueue.findMatch(repl_addr, blk->isSecure());
1248 if (repl_mshr) {
1249 // must be an outstanding upgrade or clean request
1250 // on a block we're about to replace...
1251 assert((!blk->isWritable() && repl_mshr->needsWritable()) ||
1252 repl_mshr->isCleaning());
1253
1254 // too hard to replace block with transient state
1255 // allocation failed, block not inserted
1256 return nullptr;
1257 }
1258 }
1259 }
1260
1261 // The victim will be replaced by a new entry, so increase the replacement
1262 // counter if a valid block is being replaced
1263 if (victim->isValid()) {
1264 DPRINTF(Cache, "replacement: replacing %#llx (%s) with %#llx "
1265 "(%s): %s\n", regenerateBlkAddr(victim),
1266 victim->isSecure() ? "s" : "ns",
1267 addr, is_secure ? "s" : "ns",
1268 victim->isDirty() ? "writeback" : "clean");
1269
1270 replacements++;
1271 }
1272
1273 // Evict valid blocks associated to this victim block
1274 for (const auto& blk : evict_blks) {
1275 if (blk->isValid()) {
1276 if (blk->wasPrefetched()) {
1277 unusedPrefetches++;
1278 }
1279
1280 evictBlock(blk, writebacks);
1281 }
1282 }
1283
1284 // Insert new block at victimized entry
1285 tags->insertBlock(pkt, victim);
1286
1287 return victim;
1288}
1289
1290void
1291BaseCache::invalidateBlock(CacheBlk *blk)
1292{
1293 if (blk != tempBlock)
1294 tags->invalidate(blk);
1295 blk->invalidate();
1296}
1297
1298PacketPtr
1299BaseCache::writebackBlk(CacheBlk *blk)
1300{
1301 chatty_assert(!isReadOnly || writebackClean,
1302 "Writeback from read-only cache");
1303 assert(blk && blk->isValid() && (blk->isDirty() || writebackClean));
1304
1305 writebacks[Request::wbMasterId]++;
1306
1307 RequestPtr req = std::make_shared<Request>(
1308 regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1309
1310 if (blk->isSecure())
1311 req->setFlags(Request::SECURE);
1312
1313 req->taskId(blk->task_id);
1314
1315 PacketPtr pkt =
1316 new Packet(req, blk->isDirty() ?
1317 MemCmd::WritebackDirty : MemCmd::WritebackClean);
1318
1319 DPRINTF(Cache, "Create Writeback %s writable: %d, dirty: %d\n",
1320 pkt->print(), blk->isWritable(), blk->isDirty());
1321
1322 if (blk->isWritable()) {
1323 // not asserting shared means we pass the block in modified
1324 // state, mark our own block non-writeable
1325 blk->status &= ~BlkWritable;
1326 } else {
1327 // we are in the Owned state, tell the receiver
1328 pkt->setHasSharers();
1329 }
1330
1331 // make sure the block is not marked dirty
1332 blk->status &= ~BlkDirty;
1333
1334 pkt->allocate();
1335 pkt->setDataFromBlock(blk->data, blkSize);
1336
1337 return pkt;
1338}
1339
1340PacketPtr
1341BaseCache::writecleanBlk(CacheBlk *blk, Request::Flags dest, PacketId id)
1342{
1343 RequestPtr req = std::make_shared<Request>(
1344 regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1345
1346 if (blk->isSecure()) {
1347 req->setFlags(Request::SECURE);
1348 }
1349 req->taskId(blk->task_id);
1350
1351 PacketPtr pkt = new Packet(req, MemCmd::WriteClean, blkSize, id);
1352
1353 if (dest) {
1354 req->setFlags(dest);
1355 pkt->setWriteThrough();
1356 }
1357
1358 DPRINTF(Cache, "Create %s writable: %d, dirty: %d\n", pkt->print(),
1359 blk->isWritable(), blk->isDirty());
1360
1361 if (blk->isWritable()) {
1362 // not asserting shared means we pass the block in modified
1363 // state, mark our own block non-writeable
1364 blk->status &= ~BlkWritable;
1365 } else {
1366 // we are in the Owned state, tell the receiver
1367 pkt->setHasSharers();
1368 }
1369
1370 // make sure the block is not marked dirty
1371 blk->status &= ~BlkDirty;
1372
1373 pkt->allocate();
1374 pkt->setDataFromBlock(blk->data, blkSize);
1375
1376 return pkt;
1377}
1378
1379
1380void
1381BaseCache::memWriteback()
1382{
1383 tags->forEachBlk([this](CacheBlk &blk) { writebackVisitor(blk); });
1384}
1385
1386void
1387BaseCache::memInvalidate()
1388{
1389 tags->forEachBlk([this](CacheBlk &blk) { invalidateVisitor(blk); });
1390}
1391
1392bool
1393BaseCache::isDirty() const
1394{
1395 return tags->anyBlk([](CacheBlk &blk) { return blk.isDirty(); });
1396}
1397
1398void
1399BaseCache::writebackVisitor(CacheBlk &blk)
1400{
1401 if (blk.isDirty()) {
1402 assert(blk.isValid());
1403
1404 RequestPtr request = std::make_shared<Request>(
1405 regenerateBlkAddr(&blk), blkSize, 0, Request::funcMasterId);
1406
1407 request->taskId(blk.task_id);
1408 if (blk.isSecure()) {
1409 request->setFlags(Request::SECURE);
1410 }
1411
1412 Packet packet(request, MemCmd::WriteReq);
1413 packet.dataStatic(blk.data);
1414
1415 memSidePort.sendFunctional(&packet);
1416
1417 blk.status &= ~BlkDirty;
1418 }
1419}
1420
1421void
1422BaseCache::invalidateVisitor(CacheBlk &blk)
1423{
1424 if (blk.isDirty())
1425 warn_once("Invalidating dirty cache lines. " \
1426 "Expect things to break.\n");
1427
1428 if (blk.isValid()) {
1429 assert(!blk.isDirty());
1430 invalidateBlock(&blk);
1431 }
1432}
1433
1434Tick
1435BaseCache::nextQueueReadyTime() const
1436{
1437 Tick nextReady = std::min(mshrQueue.nextReadyTime(),
1438 writeBuffer.nextReadyTime());
1439
1440 // Don't signal prefetch ready time if no MSHRs available
1441 // Will signal once enoguh MSHRs are deallocated
1442 if (prefetcher && mshrQueue.canPrefetch()) {
1443 nextReady = std::min(nextReady,
1444 prefetcher->nextPrefetchReadyTime());
1445 }
1446
1447 return nextReady;
1448}
1449
1450
1451bool
1452BaseCache::sendMSHRQueuePacket(MSHR* mshr)
1453{
1454 assert(mshr);
1455
1456 // use request from 1st target
1457 PacketPtr tgt_pkt = mshr->getTarget()->pkt;
1458
1459 DPRINTF(Cache, "%s: MSHR %s\n", __func__, tgt_pkt->print());
1460
1461 CacheBlk *blk = tags->findBlock(mshr->blkAddr, mshr->isSecure);
1462
1463 // either a prefetch that is not present upstream, or a normal
1464 // MSHR request, proceed to get the packet to send downstream
1465 PacketPtr pkt = createMissPacket(tgt_pkt, blk, mshr->needsWritable());
1466
1467 mshr->isForward = (pkt == nullptr);
1468
1469 if (mshr->isForward) {
1470 // not a cache block request, but a response is expected
1471 // make copy of current packet to forward, keep current
1472 // copy for response handling
1473 pkt = new Packet(tgt_pkt, false, true);
1474 assert(!pkt->isWrite());
1475 }
1476
1477 // play it safe and append (rather than set) the sender state,
1478 // as forwarded packets may already have existing state
1479 pkt->pushSenderState(mshr);
1480
1481 if (pkt->isClean() && blk && blk->isDirty()) {
1482 // A cache clean opearation is looking for a dirty block. Mark
1483 // the packet so that the destination xbar can determine that
1484 // there will be a follow-up write packet as well.
1485 pkt->setSatisfied();
1486 }
1487
1488 if (!memSidePort.sendTimingReq(pkt)) {
1489 // we are awaiting a retry, but we
1490 // delete the packet and will be creating a new packet
1491 // when we get the opportunity
1492 delete pkt;
1493
1494 // note that we have now masked any requestBus and
1495 // schedSendEvent (we will wait for a retry before
1496 // doing anything), and this is so even if we do not
1497 // care about this packet and might override it before
1498 // it gets retried
1499 return true;
1500 } else {
1501 // As part of the call to sendTimingReq the packet is
1502 // forwarded to all neighbouring caches (and any caches
1503 // above them) as a snoop. Thus at this point we know if
1504 // any of the neighbouring caches are responding, and if
1505 // so, we know it is dirty, and we can determine if it is
1506 // being passed as Modified, making our MSHR the ordering
1507 // point
1508 bool pending_modified_resp = !pkt->hasSharers() &&
1509 pkt->cacheResponding();
1510 markInService(mshr, pending_modified_resp);
1511
1512 if (pkt->isClean() && blk && blk->isDirty()) {
1513 // A cache clean opearation is looking for a dirty
1514 // block. If a dirty block is encountered a WriteClean
1515 // will update any copies to the path to the memory
1516 // until the point of reference.
1517 DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
1518 __func__, pkt->print(), blk->print());
1519 PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(),
1520 pkt->id);
1521 PacketList writebacks;
1522 writebacks.push_back(wb_pkt);
1523 doWritebacks(writebacks, 0);
1524 }
1525
1526 return false;
1527 }
1528}
1529
1530bool
1531BaseCache::sendWriteQueuePacket(WriteQueueEntry* wq_entry)
1532{
1533 assert(wq_entry);
1534
1535 // always a single target for write queue entries
1536 PacketPtr tgt_pkt = wq_entry->getTarget()->pkt;
1537
1538 DPRINTF(Cache, "%s: write %s\n", __func__, tgt_pkt->print());
1539
1540 // forward as is, both for evictions and uncacheable writes
1541 if (!memSidePort.sendTimingReq(tgt_pkt)) {
1542 // note that we have now masked any requestBus and
1543 // schedSendEvent (we will wait for a retry before
1544 // doing anything), and this is so even if we do not
1545 // care about this packet and might override it before
1546 // it gets retried
1547 return true;
1548 } else {
1549 markInService(wq_entry);
1550 return false;
1551 }
1552}
1553
1554void
1555BaseCache::serialize(CheckpointOut &cp) const
1556{
1557 bool dirty(isDirty());
1558
1559 if (dirty) {
1560 warn("*** The cache still contains dirty data. ***\n");
1561 warn(" Make sure to drain the system using the correct flags.\n");
1562 warn(" This checkpoint will not restore correctly " \
1563 "and dirty data in the cache will be lost!\n");
1564 }
1565
1566 // Since we don't checkpoint the data in the cache, any dirty data
1567 // will be lost when restoring from a checkpoint of a system that
1568 // wasn't drained properly. Flag the checkpoint as invalid if the
1569 // cache contains dirty data.
1570 bool bad_checkpoint(dirty);
1571 SERIALIZE_SCALAR(bad_checkpoint);
1572}
1573
1574void
1575BaseCache::unserialize(CheckpointIn &cp)
1576{
1577 bool bad_checkpoint;
1578 UNSERIALIZE_SCALAR(bad_checkpoint);
1579 if (bad_checkpoint) {
1580 fatal("Restoring from checkpoints with dirty caches is not "
1581 "supported in the classic memory system. Please remove any "
1582 "caches or drain them properly before taking checkpoints.\n");
1583 }
1584}
1585
1586void
1587BaseCache::regStats()
1588{
1589 MemObject::regStats();
1590
1591 using namespace Stats;
1592
1593 // Hit statistics
1594 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1595 MemCmd cmd(access_idx);
1596 const string &cstr = cmd.toString();
1597
1598 hits[access_idx]
1599 .init(system->maxMasters())
1600 .name(name() + "." + cstr + "_hits")
1601 .desc("number of " + cstr + " hits")
1602 .flags(total | nozero | nonan)
1603 ;
1604 for (int i = 0; i < system->maxMasters(); i++) {
1605 hits[access_idx].subname(i, system->getMasterName(i));
1606 }
1607 }
1608
1609// These macros make it easier to sum the right subset of commands and
1610// to change the subset of commands that are considered "demand" vs
1611// "non-demand"
1612#define SUM_DEMAND(s) \
1613 (s[MemCmd::ReadReq] + s[MemCmd::WriteReq] + s[MemCmd::WriteLineReq] + \
1614 s[MemCmd::ReadExReq] + s[MemCmd::ReadCleanReq] + s[MemCmd::ReadSharedReq])
1615
1616// should writebacks be included here? prior code was inconsistent...
1617#define SUM_NON_DEMAND(s) \
1618 (s[MemCmd::SoftPFReq] + s[MemCmd::HardPFReq])
1619
1620 demandHits
1621 .name(name() + ".demand_hits")
1622 .desc("number of demand (read+write) hits")
1623 .flags(total | nozero | nonan)
1624 ;
1625 demandHits = SUM_DEMAND(hits);
1626 for (int i = 0; i < system->maxMasters(); i++) {
1627 demandHits.subname(i, system->getMasterName(i));
1628 }
1629
1630 overallHits
1631 .name(name() + ".overall_hits")
1632 .desc("number of overall hits")
1633 .flags(total | nozero | nonan)
1634 ;
1635 overallHits = demandHits + SUM_NON_DEMAND(hits);
1636 for (int i = 0; i < system->maxMasters(); i++) {
1637 overallHits.subname(i, system->getMasterName(i));
1638 }
1639
1640 // Miss statistics
1641 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1642 MemCmd cmd(access_idx);
1643 const string &cstr = cmd.toString();
1644
1645 misses[access_idx]
1646 .init(system->maxMasters())
1647 .name(name() + "." + cstr + "_misses")
1648 .desc("number of " + cstr + " misses")
1649 .flags(total | nozero | nonan)
1650 ;
1651 for (int i = 0; i < system->maxMasters(); i++) {
1652 misses[access_idx].subname(i, system->getMasterName(i));
1653 }
1654 }
1655
1656 demandMisses
1657 .name(name() + ".demand_misses")
1658 .desc("number of demand (read+write) misses")
1659 .flags(total | nozero | nonan)
1660 ;
1661 demandMisses = SUM_DEMAND(misses);
1662 for (int i = 0; i < system->maxMasters(); i++) {
1663 demandMisses.subname(i, system->getMasterName(i));
1664 }
1665
1666 overallMisses
1667 .name(name() + ".overall_misses")
1668 .desc("number of overall misses")
1669 .flags(total | nozero | nonan)
1670 ;
1671 overallMisses = demandMisses + SUM_NON_DEMAND(misses);
1672 for (int i = 0; i < system->maxMasters(); i++) {
1673 overallMisses.subname(i, system->getMasterName(i));
1674 }
1675
1676 // Miss latency statistics
1677 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1678 MemCmd cmd(access_idx);
1679 const string &cstr = cmd.toString();
1680
1681 missLatency[access_idx]
1682 .init(system->maxMasters())
1683 .name(name() + "." + cstr + "_miss_latency")
1684 .desc("number of " + cstr + " miss cycles")
1685 .flags(total | nozero | nonan)
1686 ;
1687 for (int i = 0; i < system->maxMasters(); i++) {
1688 missLatency[access_idx].subname(i, system->getMasterName(i));
1689 }
1690 }
1691
1692 demandMissLatency
1693 .name(name() + ".demand_miss_latency")
1694 .desc("number of demand (read+write) miss cycles")
1695 .flags(total | nozero | nonan)
1696 ;
1697 demandMissLatency = SUM_DEMAND(missLatency);
1698 for (int i = 0; i < system->maxMasters(); i++) {
1699 demandMissLatency.subname(i, system->getMasterName(i));
1700 }
1701
1702 overallMissLatency
1703 .name(name() + ".overall_miss_latency")
1704 .desc("number of overall miss cycles")
1705 .flags(total | nozero | nonan)
1706 ;
1707 overallMissLatency = demandMissLatency + SUM_NON_DEMAND(missLatency);
1708 for (int i = 0; i < system->maxMasters(); i++) {
1709 overallMissLatency.subname(i, system->getMasterName(i));
1710 }
1711
1712 // access formulas
1713 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1714 MemCmd cmd(access_idx);
1715 const string &cstr = cmd.toString();
1716
1717 accesses[access_idx]
1718 .name(name() + "." + cstr + "_accesses")
1719 .desc("number of " + cstr + " accesses(hits+misses)")
1720 .flags(total | nozero | nonan)
1721 ;
1722 accesses[access_idx] = hits[access_idx] + misses[access_idx];
1723
1724 for (int i = 0; i < system->maxMasters(); i++) {
1725 accesses[access_idx].subname(i, system->getMasterName(i));
1726 }
1727 }
1728
1729 demandAccesses
1730 .name(name() + ".demand_accesses")
1731 .desc("number of demand (read+write) accesses")
1732 .flags(total | nozero | nonan)
1733 ;
1734 demandAccesses = demandHits + demandMisses;
1735 for (int i = 0; i < system->maxMasters(); i++) {
1736 demandAccesses.subname(i, system->getMasterName(i));
1737 }
1738
1739 overallAccesses
1740 .name(name() + ".overall_accesses")
1741 .desc("number of overall (read+write) accesses")
1742 .flags(total | nozero | nonan)
1743 ;
1744 overallAccesses = overallHits + overallMisses;
1745 for (int i = 0; i < system->maxMasters(); i++) {
1746 overallAccesses.subname(i, system->getMasterName(i));
1747 }
1748
1749 // miss rate formulas
1750 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1751 MemCmd cmd(access_idx);
1752 const string &cstr = cmd.toString();
1753
1754 missRate[access_idx]
1755 .name(name() + "." + cstr + "_miss_rate")
1756 .desc("miss rate for " + cstr + " accesses")
1757 .flags(total | nozero | nonan)
1758 ;
1759 missRate[access_idx] = misses[access_idx] / accesses[access_idx];
1760
1761 for (int i = 0; i < system->maxMasters(); i++) {
1762 missRate[access_idx].subname(i, system->getMasterName(i));
1763 }
1764 }
1765
1766 demandMissRate
1767 .name(name() + ".demand_miss_rate")
1768 .desc("miss rate for demand accesses")
1769 .flags(total | nozero | nonan)
1770 ;
1771 demandMissRate = demandMisses / demandAccesses;
1772 for (int i = 0; i < system->maxMasters(); i++) {
1773 demandMissRate.subname(i, system->getMasterName(i));
1774 }
1775
1776 overallMissRate
1777 .name(name() + ".overall_miss_rate")
1778 .desc("miss rate for overall accesses")
1779 .flags(total | nozero | nonan)
1780 ;
1781 overallMissRate = overallMisses / overallAccesses;
1782 for (int i = 0; i < system->maxMasters(); i++) {
1783 overallMissRate.subname(i, system->getMasterName(i));
1784 }
1785
1786 // miss latency formulas
1787 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1788 MemCmd cmd(access_idx);
1789 const string &cstr = cmd.toString();
1790
1791 avgMissLatency[access_idx]
1792 .name(name() + "." + cstr + "_avg_miss_latency")
1793 .desc("average " + cstr + " miss latency")
1794 .flags(total | nozero | nonan)
1795 ;
1796 avgMissLatency[access_idx] =
1797 missLatency[access_idx] / misses[access_idx];
1798
1799 for (int i = 0; i < system->maxMasters(); i++) {
1800 avgMissLatency[access_idx].subname(i, system->getMasterName(i));
1801 }
1802 }
1803
1804 demandAvgMissLatency
1805 .name(name() + ".demand_avg_miss_latency")
1806 .desc("average overall miss latency")
1807 .flags(total | nozero | nonan)
1808 ;
1809 demandAvgMissLatency = demandMissLatency / demandMisses;
1810 for (int i = 0; i < system->maxMasters(); i++) {
1811 demandAvgMissLatency.subname(i, system->getMasterName(i));
1812 }
1813
1814 overallAvgMissLatency
1815 .name(name() + ".overall_avg_miss_latency")
1816 .desc("average overall miss latency")
1817 .flags(total | nozero | nonan)
1818 ;
1819 overallAvgMissLatency = overallMissLatency / overallMisses;
1820 for (int i = 0; i < system->maxMasters(); i++) {
1821 overallAvgMissLatency.subname(i, system->getMasterName(i));
1822 }
1823
1824 blocked_cycles.init(NUM_BLOCKED_CAUSES);
1825 blocked_cycles
1826 .name(name() + ".blocked_cycles")
1827 .desc("number of cycles access was blocked")
1828 .subname(Blocked_NoMSHRs, "no_mshrs")
1829 .subname(Blocked_NoTargets, "no_targets")
1830 ;
1831
1832
1833 blocked_causes.init(NUM_BLOCKED_CAUSES);
1834 blocked_causes
1835 .name(name() + ".blocked")
1836 .desc("number of cycles access was blocked")
1837 .subname(Blocked_NoMSHRs, "no_mshrs")
1838 .subname(Blocked_NoTargets, "no_targets")
1839 ;
1840
1841 avg_blocked
1842 .name(name() + ".avg_blocked_cycles")
1843 .desc("average number of cycles each access was blocked")
1844 .subname(Blocked_NoMSHRs, "no_mshrs")
1845 .subname(Blocked_NoTargets, "no_targets")
1846 ;
1847
1848 avg_blocked = blocked_cycles / blocked_causes;
1849
1850 unusedPrefetches
1851 .name(name() + ".unused_prefetches")
1852 .desc("number of HardPF blocks evicted w/o reference")
1853 .flags(nozero)
1854 ;
1855
1856 writebacks
1857 .init(system->maxMasters())
1858 .name(name() + ".writebacks")
1859 .desc("number of writebacks")
1860 .flags(total | nozero | nonan)
1861 ;
1862 for (int i = 0; i < system->maxMasters(); i++) {
1863 writebacks.subname(i, system->getMasterName(i));
1864 }
1865
1866 // MSHR statistics
1867 // MSHR hit statistics
1868 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1869 MemCmd cmd(access_idx);
1870 const string &cstr = cmd.toString();
1871
1872 mshr_hits[access_idx]
1873 .init(system->maxMasters())
1874 .name(name() + "." + cstr + "_mshr_hits")
1875 .desc("number of " + cstr + " MSHR hits")
1876 .flags(total | nozero | nonan)
1877 ;
1878 for (int i = 0; i < system->maxMasters(); i++) {
1879 mshr_hits[access_idx].subname(i, system->getMasterName(i));
1880 }
1881 }
1882
1883 demandMshrHits
1884 .name(name() + ".demand_mshr_hits")
1885 .desc("number of demand (read+write) MSHR hits")
1886 .flags(total | nozero | nonan)
1887 ;
1888 demandMshrHits = SUM_DEMAND(mshr_hits);
1889 for (int i = 0; i < system->maxMasters(); i++) {
1890 demandMshrHits.subname(i, system->getMasterName(i));
1891 }
1892
1893 overallMshrHits
1894 .name(name() + ".overall_mshr_hits")
1895 .desc("number of overall MSHR hits")
1896 .flags(total | nozero | nonan)
1897 ;
1898 overallMshrHits = demandMshrHits + SUM_NON_DEMAND(mshr_hits);
1899 for (int i = 0; i < system->maxMasters(); i++) {
1900 overallMshrHits.subname(i, system->getMasterName(i));
1901 }
1902
1903 // MSHR miss statistics
1904 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1905 MemCmd cmd(access_idx);
1906 const string &cstr = cmd.toString();
1907
1908 mshr_misses[access_idx]
1909 .init(system->maxMasters())
1910 .name(name() + "." + cstr + "_mshr_misses")
1911 .desc("number of " + cstr + " MSHR misses")
1912 .flags(total | nozero | nonan)
1913 ;
1914 for (int i = 0; i < system->maxMasters(); i++) {
1915 mshr_misses[access_idx].subname(i, system->getMasterName(i));
1916 }
1917 }
1918
1919 demandMshrMisses
1920 .name(name() + ".demand_mshr_misses")
1921 .desc("number of demand (read+write) MSHR misses")
1922 .flags(total | nozero | nonan)
1923 ;
1924 demandMshrMisses = SUM_DEMAND(mshr_misses);
1925 for (int i = 0; i < system->maxMasters(); i++) {
1926 demandMshrMisses.subname(i, system->getMasterName(i));
1927 }
1928
1929 overallMshrMisses
1930 .name(name() + ".overall_mshr_misses")
1931 .desc("number of overall MSHR misses")
1932 .flags(total | nozero | nonan)
1933 ;
1934 overallMshrMisses = demandMshrMisses + SUM_NON_DEMAND(mshr_misses);
1935 for (int i = 0; i < system->maxMasters(); i++) {
1936 overallMshrMisses.subname(i, system->getMasterName(i));
1937 }
1938
1939 // MSHR miss latency statistics
1940 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1941 MemCmd cmd(access_idx);
1942 const string &cstr = cmd.toString();
1943
1944 mshr_miss_latency[access_idx]
1945 .init(system->maxMasters())
1946 .name(name() + "." + cstr + "_mshr_miss_latency")
1947 .desc("number of " + cstr + " MSHR miss cycles")
1948 .flags(total | nozero | nonan)
1949 ;
1950 for (int i = 0; i < system->maxMasters(); i++) {
1951 mshr_miss_latency[access_idx].subname(i, system->getMasterName(i));
1952 }
1953 }
1954
1955 demandMshrMissLatency
1956 .name(name() + ".demand_mshr_miss_latency")
1957 .desc("number of demand (read+write) MSHR miss cycles")
1958 .flags(total | nozero | nonan)
1959 ;
1960 demandMshrMissLatency = SUM_DEMAND(mshr_miss_latency);
1961 for (int i = 0; i < system->maxMasters(); i++) {
1962 demandMshrMissLatency.subname(i, system->getMasterName(i));
1963 }
1964
1965 overallMshrMissLatency
1966 .name(name() + ".overall_mshr_miss_latency")
1967 .desc("number of overall MSHR miss cycles")
1968 .flags(total | nozero | nonan)
1969 ;
1970 overallMshrMissLatency =
1971 demandMshrMissLatency + SUM_NON_DEMAND(mshr_miss_latency);
1972 for (int i = 0; i < system->maxMasters(); i++) {
1973 overallMshrMissLatency.subname(i, system->getMasterName(i));
1974 }
1975
1976 // MSHR uncacheable statistics
1977 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1978 MemCmd cmd(access_idx);
1979 const string &cstr = cmd.toString();
1980
1981 mshr_uncacheable[access_idx]
1982 .init(system->maxMasters())
1983 .name(name() + "." + cstr + "_mshr_uncacheable")
1984 .desc("number of " + cstr + " MSHR uncacheable")
1985 .flags(total | nozero | nonan)
1986 ;
1987 for (int i = 0; i < system->maxMasters(); i++) {
1988 mshr_uncacheable[access_idx].subname(i, system->getMasterName(i));
1989 }
1990 }
1991
1992 overallMshrUncacheable
1993 .name(name() + ".overall_mshr_uncacheable_misses")
1994 .desc("number of overall MSHR uncacheable misses")
1995 .flags(total | nozero | nonan)
1996 ;
1997 overallMshrUncacheable =
1998 SUM_DEMAND(mshr_uncacheable) + SUM_NON_DEMAND(mshr_uncacheable);
1999 for (int i = 0; i < system->maxMasters(); i++) {
2000 overallMshrUncacheable.subname(i, system->getMasterName(i));
2001 }
2002
2003 // MSHR miss latency statistics
2004 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2005 MemCmd cmd(access_idx);
2006 const string &cstr = cmd.toString();
2007
2008 mshr_uncacheable_lat[access_idx]
2009 .init(system->maxMasters())
2010 .name(name() + "." + cstr + "_mshr_uncacheable_latency")
2011 .desc("number of " + cstr + " MSHR uncacheable cycles")
2012 .flags(total | nozero | nonan)
2013 ;
2014 for (int i = 0; i < system->maxMasters(); i++) {
2015 mshr_uncacheable_lat[access_idx].subname(
2016 i, system->getMasterName(i));
2017 }
2018 }
2019
2020 overallMshrUncacheableLatency
2021 .name(name() + ".overall_mshr_uncacheable_latency")
2022 .desc("number of overall MSHR uncacheable cycles")
2023 .flags(total | nozero | nonan)
2024 ;
2025 overallMshrUncacheableLatency =
2026 SUM_DEMAND(mshr_uncacheable_lat) +
2027 SUM_NON_DEMAND(mshr_uncacheable_lat);
2028 for (int i = 0; i < system->maxMasters(); i++) {
2029 overallMshrUncacheableLatency.subname(i, system->getMasterName(i));
2030 }
2031
2032#if 0
2033 // MSHR access formulas
2034 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2035 MemCmd cmd(access_idx);
2036 const string &cstr = cmd.toString();
2037
2038 mshrAccesses[access_idx]
2039 .name(name() + "." + cstr + "_mshr_accesses")
2040 .desc("number of " + cstr + " mshr accesses(hits+misses)")
2041 .flags(total | nozero | nonan)
2042 ;
2043 mshrAccesses[access_idx] =
2044 mshr_hits[access_idx] + mshr_misses[access_idx]
2045 + mshr_uncacheable[access_idx];
2046 }
2047
2048 demandMshrAccesses
2049 .name(name() + ".demand_mshr_accesses")
2050 .desc("number of demand (read+write) mshr accesses")
2051 .flags(total | nozero | nonan)
2052 ;
2053 demandMshrAccesses = demandMshrHits + demandMshrMisses;
2054
2055 overallMshrAccesses
2056 .name(name() + ".overall_mshr_accesses")
2057 .desc("number of overall (read+write) mshr accesses")
2058 .flags(total | nozero | nonan)
2059 ;
2060 overallMshrAccesses = overallMshrHits + overallMshrMisses
2061 + overallMshrUncacheable;
2062#endif
2063
2064 // MSHR miss rate formulas
2065 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2066 MemCmd cmd(access_idx);
2067 const string &cstr = cmd.toString();
2068
2069 mshrMissRate[access_idx]
2070 .name(name() + "." + cstr + "_mshr_miss_rate")
2071 .desc("mshr miss rate for " + cstr + " accesses")
2072 .flags(total | nozero | nonan)
2073 ;
2074 mshrMissRate[access_idx] =
2075 mshr_misses[access_idx] / accesses[access_idx];
2076
2077 for (int i = 0; i < system->maxMasters(); i++) {
2078 mshrMissRate[access_idx].subname(i, system->getMasterName(i));
2079 }
2080 }
2081
2082 demandMshrMissRate
2083 .name(name() + ".demand_mshr_miss_rate")
2084 .desc("mshr miss rate for demand accesses")
2085 .flags(total | nozero | nonan)
2086 ;
2087 demandMshrMissRate = demandMshrMisses / demandAccesses;
2088 for (int i = 0; i < system->maxMasters(); i++) {
2089 demandMshrMissRate.subname(i, system->getMasterName(i));
2090 }
2091
2092 overallMshrMissRate
2093 .name(name() + ".overall_mshr_miss_rate")
2094 .desc("mshr miss rate for overall accesses")
2095 .flags(total | nozero | nonan)
2096 ;
2097 overallMshrMissRate = overallMshrMisses / overallAccesses;
2098 for (int i = 0; i < system->maxMasters(); i++) {
2099 overallMshrMissRate.subname(i, system->getMasterName(i));
2100 }
2101
2102 // mshrMiss latency formulas
2103 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2104 MemCmd cmd(access_idx);
2105 const string &cstr = cmd.toString();
2106
2107 avgMshrMissLatency[access_idx]
2108 .name(name() + "." + cstr + "_avg_mshr_miss_latency")
2109 .desc("average " + cstr + " mshr miss latency")
2110 .flags(total | nozero | nonan)
2111 ;
2112 avgMshrMissLatency[access_idx] =
2113 mshr_miss_latency[access_idx] / mshr_misses[access_idx];
2114
2115 for (int i = 0; i < system->maxMasters(); i++) {
2116 avgMshrMissLatency[access_idx].subname(
2117 i, system->getMasterName(i));
2118 }
2119 }
2120
2121 demandAvgMshrMissLatency
2122 .name(name() + ".demand_avg_mshr_miss_latency")
2123 .desc("average overall mshr miss latency")
2124 .flags(total | nozero | nonan)
2125 ;
2126 demandAvgMshrMissLatency = demandMshrMissLatency / demandMshrMisses;
2127 for (int i = 0; i < system->maxMasters(); i++) {
2128 demandAvgMshrMissLatency.subname(i, system->getMasterName(i));
2129 }
2130
2131 overallAvgMshrMissLatency
2132 .name(name() + ".overall_avg_mshr_miss_latency")
2133 .desc("average overall mshr miss latency")
2134 .flags(total | nozero | nonan)
2135 ;
2136 overallAvgMshrMissLatency = overallMshrMissLatency / overallMshrMisses;
2137 for (int i = 0; i < system->maxMasters(); i++) {
2138 overallAvgMshrMissLatency.subname(i, system->getMasterName(i));
2139 }
2140
2141 // mshrUncacheable latency formulas
2142 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2143 MemCmd cmd(access_idx);
2144 const string &cstr = cmd.toString();
2145
2146 avgMshrUncacheableLatency[access_idx]
2147 .name(name() + "." + cstr + "_avg_mshr_uncacheable_latency")
2148 .desc("average " + cstr + " mshr uncacheable latency")
2149 .flags(total | nozero | nonan)
2150 ;
2151 avgMshrUncacheableLatency[access_idx] =
2152 mshr_uncacheable_lat[access_idx] / mshr_uncacheable[access_idx];
2153
2154 for (int i = 0; i < system->maxMasters(); i++) {
2155 avgMshrUncacheableLatency[access_idx].subname(
2156 i, system->getMasterName(i));
2157 }
2158 }
2159
2160 overallAvgMshrUncacheableLatency
2161 .name(name() + ".overall_avg_mshr_uncacheable_latency")
2162 .desc("average overall mshr uncacheable latency")
2163 .flags(total | nozero | nonan)
2164 ;
2165 overallAvgMshrUncacheableLatency =
2166 overallMshrUncacheableLatency / overallMshrUncacheable;
2167 for (int i = 0; i < system->maxMasters(); i++) {
2168 overallAvgMshrUncacheableLatency.subname(i, system->getMasterName(i));
2169 }
2170
2171 replacements
2172 .name(name() + ".replacements")
2173 .desc("number of replacements")
2174 ;
2175}
2176
2177///////////////
2178//
2179// CpuSidePort
2180//
2181///////////////
2182bool
2183BaseCache::CpuSidePort::recvTimingSnoopResp(PacketPtr pkt)
2184{
2185 // Snoops shouldn't happen when bypassing caches
2186 assert(!cache->system->bypassCaches());
2187
2188 assert(pkt->isResponse());
2189
2190 // Express snoop responses from master to slave, e.g., from L1 to L2
2191 cache->recvTimingSnoopResp(pkt);
2192 return true;
2193}
2194
2195
2196bool
2197BaseCache::CpuSidePort::tryTiming(PacketPtr pkt)
2198{
2199 if (cache->system->bypassCaches() || pkt->isExpressSnoop()) {
2200 // always let express snoop packets through even if blocked
2201 return true;
2202 } else if (blocked || mustSendRetry) {
2203 // either already committed to send a retry, or blocked
2204 mustSendRetry = true;
2205 return false;
2206 }
2207 mustSendRetry = false;
2208 return true;
2209}
2210
2211bool
2212BaseCache::CpuSidePort::recvTimingReq(PacketPtr pkt)
2213{
2214 assert(pkt->isRequest());
2215
2216 if (cache->system->bypassCaches()) {
2217 // Just forward the packet if caches are disabled.
2218 // @todo This should really enqueue the packet rather
2219 bool M5_VAR_USED success = cache->memSidePort.sendTimingReq(pkt);
2220 assert(success);
2221 return true;
2222 } else if (tryTiming(pkt)) {
2223 cache->recvTimingReq(pkt);
2224 return true;
2225 }
2226 return false;
2227}
2228
2229Tick
2230BaseCache::CpuSidePort::recvAtomic(PacketPtr pkt)
2231{
2232 if (cache->system->bypassCaches()) {
2233 // Forward the request if the system is in cache bypass mode.
2234 return cache->memSidePort.sendAtomic(pkt);
2235 } else {
2236 return cache->recvAtomic(pkt);
2237 }
2238}
2239
2240void
2241BaseCache::CpuSidePort::recvFunctional(PacketPtr pkt)
2242{
2243 if (cache->system->bypassCaches()) {
2244 // The cache should be flushed if we are in cache bypass mode,
2245 // so we don't need to check if we need to update anything.
2246 cache->memSidePort.sendFunctional(pkt);
2247 return;
2248 }
2249
2250 // functional request
2251 cache->functionalAccess(pkt, true);
2252}
2253
2254AddrRangeList
2255BaseCache::CpuSidePort::getAddrRanges() const
2256{
2257 return cache->getAddrRanges();
2258}
2259
2260
2261BaseCache::
2262CpuSidePort::CpuSidePort(const std::string &_name, BaseCache *_cache,
2263 const std::string &_label)
2264 : CacheSlavePort(_name, _cache, _label), cache(_cache)
2265{
2266}
2267
2268///////////////
2269//
2270// MemSidePort
2271//
2272///////////////
2273bool
2274BaseCache::MemSidePort::recvTimingResp(PacketPtr pkt)
2275{
2276 cache->recvTimingResp(pkt);
2277 return true;
2278}
2279
2280// Express snooping requests to memside port
2281void
2282BaseCache::MemSidePort::recvTimingSnoopReq(PacketPtr pkt)
2283{
2284 // Snoops shouldn't happen when bypassing caches
2285 assert(!cache->system->bypassCaches());
2286
2287 // handle snooping requests
2288 cache->recvTimingSnoopReq(pkt);
2289}
2290
2291Tick
2292BaseCache::MemSidePort::recvAtomicSnoop(PacketPtr pkt)
2293{
2294 // Snoops shouldn't happen when bypassing caches
2295 assert(!cache->system->bypassCaches());
2296
2297 return cache->recvAtomicSnoop(pkt);
2298}
2299
2300void
2301BaseCache::MemSidePort::recvFunctionalSnoop(PacketPtr pkt)
2302{
2303 // Snoops shouldn't happen when bypassing caches
2304 assert(!cache->system->bypassCaches());
2305
2306 // functional snoop (note that in contrast to atomic we don't have
2307 // a specific functionalSnoop method, as they have the same
2308 // behaviour regardless)
2309 cache->functionalAccess(pkt, false);
2310}
2311
2312void
2313BaseCache::CacheReqPacketQueue::sendDeferredPacket()
2314{
2315 // sanity check
2316 assert(!waitingOnRetry);
2317
2318 // there should never be any deferred request packets in the
2319 // queue, instead we resly on the cache to provide the packets
2320 // from the MSHR queue or write queue
2321 assert(deferredPacketReadyTime() == MaxTick);
2322
2323 // check for request packets (requests & writebacks)
2324 QueueEntry* entry = cache.getNextQueueEntry();
2325
2326 if (!entry) {
2327 // can happen if e.g. we attempt a writeback and fail, but
2328 // before the retry, the writeback is eliminated because
2329 // we snoop another cache's ReadEx.
2330 } else {
2331 // let our snoop responses go first if there are responses to
2332 // the same addresses
2333 if (checkConflictingSnoop(entry->blkAddr)) {
2334 return;
2335 }
2336 waitingOnRetry = entry->sendPacket(cache);
2337 }
2338
2339 // if we succeeded and are not waiting for a retry, schedule the
2340 // next send considering when the next queue is ready, note that
2341 // snoop responses have their own packet queue and thus schedule
2342 // their own events
2343 if (!waitingOnRetry) {
2344 schedSendEvent(cache.nextQueueReadyTime());
2345 }
2346}
2347
2348BaseCache::MemSidePort::MemSidePort(const std::string &_name,
2349 BaseCache *_cache,
2350 const std::string &_label)
2351 : CacheMasterPort(_name, _cache, _reqQueue, _snoopRespQueue),
2352 _reqQueue(*_cache, *this, _snoopRespQueue, _label),
2353 _snoopRespQueue(*_cache, *this, _label), cache(_cache)
2354{
2355}
| 125 delete tempBlock;
126}
127
128void
129BaseCache::CacheSlavePort::setBlocked()
130{
131 assert(!blocked);
132 DPRINTF(CachePort, "Port is blocking new requests\n");
133 blocked = true;
134 // if we already scheduled a retry in this cycle, but it has not yet
135 // happened, cancel it
136 if (sendRetryEvent.scheduled()) {
137 owner.deschedule(sendRetryEvent);
138 DPRINTF(CachePort, "Port descheduled retry\n");
139 mustSendRetry = true;
140 }
141}
142
143void
144BaseCache::CacheSlavePort::clearBlocked()
145{
146 assert(blocked);
147 DPRINTF(CachePort, "Port is accepting new requests\n");
148 blocked = false;
149 if (mustSendRetry) {
150 // @TODO: need to find a better time (next cycle?)
151 owner.schedule(sendRetryEvent, curTick() + 1);
152 }
153}
154
155void
156BaseCache::CacheSlavePort::processSendRetry()
157{
158 DPRINTF(CachePort, "Port is sending retry\n");
159
160 // reset the flag and call retry
161 mustSendRetry = false;
162 sendRetryReq();
163}
164
165Addr
166BaseCache::regenerateBlkAddr(CacheBlk* blk)
167{
168 if (blk != tempBlock) {
169 return tags->regenerateBlkAddr(blk);
170 } else {
171 return tempBlock->getAddr();
172 }
173}
174
175void
176BaseCache::init()
177{
178 if (!cpuSidePort.isConnected() || !memSidePort.isConnected())
179 fatal("Cache ports on %s are not connected\n", name());
180 cpuSidePort.sendRangeChange();
181 forwardSnoops = cpuSidePort.isSnooping();
182}
183
184BaseMasterPort &
185BaseCache::getMasterPort(const std::string &if_name, PortID idx)
186{
187 if (if_name == "mem_side") {
188 return memSidePort;
189 } else {
190 return MemObject::getMasterPort(if_name, idx);
191 }
192}
193
194BaseSlavePort &
195BaseCache::getSlavePort(const std::string &if_name, PortID idx)
196{
197 if (if_name == "cpu_side") {
198 return cpuSidePort;
199 } else {
200 return MemObject::getSlavePort(if_name, idx);
201 }
202}
203
204bool
205BaseCache::inRange(Addr addr) const
206{
207 for (const auto& r : addrRanges) {
208 if (r.contains(addr)) {
209 return true;
210 }
211 }
212 return false;
213}
214
215void
216BaseCache::handleTimingReqHit(PacketPtr pkt, CacheBlk *blk, Tick request_time)
217{
218 if (pkt->needsResponse()) {
219 pkt->makeTimingResponse();
220 // @todo: Make someone pay for this
221 pkt->headerDelay = pkt->payloadDelay = 0;
222
223 // In this case we are considering request_time that takes
224 // into account the delay of the xbar, if any, and just
225 // lat, neglecting responseLatency, modelling hit latency
226 // just as lookupLatency or or the value of lat overriden
227 // by access(), that calls accessBlock() function.
228 cpuSidePort.schedTimingResp(pkt, request_time, true);
229 } else {
230 DPRINTF(Cache, "%s satisfied %s, no response needed\n", __func__,
231 pkt->print());
232
233 // queue the packet for deletion, as the sending cache is
234 // still relying on it; if the block is found in access(),
235 // CleanEvict and Writeback messages will be deleted
236 // here as well
237 pendingDelete.reset(pkt);
238 }
239}
240
241void
242BaseCache::handleTimingReqMiss(PacketPtr pkt, MSHR *mshr, CacheBlk *blk,
243 Tick forward_time, Tick request_time)
244{
245 if (mshr) {
246 /// MSHR hit
247 /// @note writebacks will be checked in getNextMSHR()
248 /// for any conflicting requests to the same block
249
250 //@todo remove hw_pf here
251
252 // Coalesce unless it was a software prefetch (see above).
253 if (pkt) {
254 assert(!pkt->isWriteback());
255 // CleanEvicts corresponding to blocks which have
256 // outstanding requests in MSHRs are simply sunk here
257 if (pkt->cmd == MemCmd::CleanEvict) {
258 pendingDelete.reset(pkt);
259 } else if (pkt->cmd == MemCmd::WriteClean) {
260 // A WriteClean should never coalesce with any
261 // outstanding cache maintenance requests.
262
263 // We use forward_time here because there is an
264 // uncached memory write, forwarded to WriteBuffer.
265 allocateWriteBuffer(pkt, forward_time);
266 } else {
267 DPRINTF(Cache, "%s coalescing MSHR for %s\n", __func__,
268 pkt->print());
269
270 assert(pkt->req->masterId() < system->maxMasters());
271 mshr_hits[pkt->cmdToIndex()][pkt->req->masterId()]++;
272
273 // We use forward_time here because it is the same
274 // considering new targets. We have multiple
275 // requests for the same address here. It
276 // specifies the latency to allocate an internal
277 // buffer and to schedule an event to the queued
278 // port and also takes into account the additional
279 // delay of the xbar.
280 mshr->allocateTarget(pkt, forward_time, order++,
281 allocOnFill(pkt->cmd));
282 if (mshr->getNumTargets() == numTarget) {
283 noTargetMSHR = mshr;
284 setBlocked(Blocked_NoTargets);
285 // need to be careful with this... if this mshr isn't
286 // ready yet (i.e. time > curTick()), we don't want to
287 // move it ahead of mshrs that are ready
288 // mshrQueue.moveToFront(mshr);
289 }
290 }
291 }
292 } else {
293 // no MSHR
294 assert(pkt->req->masterId() < system->maxMasters());
295 mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
296
297 if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean) {
298 // We use forward_time here because there is an
299 // writeback or writeclean, forwarded to WriteBuffer.
300 allocateWriteBuffer(pkt, forward_time);
301 } else {
302 if (blk && blk->isValid()) {
303 // If we have a write miss to a valid block, we
304 // need to mark the block non-readable. Otherwise
305 // if we allow reads while there's an outstanding
306 // write miss, the read could return stale data
307 // out of the cache block... a more aggressive
308 // system could detect the overlap (if any) and
309 // forward data out of the MSHRs, but we don't do
310 // that yet. Note that we do need to leave the
311 // block valid so that it stays in the cache, in
312 // case we get an upgrade response (and hence no
313 // new data) when the write miss completes.
314 // As long as CPUs do proper store/load forwarding
315 // internally, and have a sufficiently weak memory
316 // model, this is probably unnecessary, but at some
317 // point it must have seemed like we needed it...
318 assert((pkt->needsWritable() && !blk->isWritable()) ||
319 pkt->req->isCacheMaintenance());
320 blk->status &= ~BlkReadable;
321 }
322 // Here we are using forward_time, modelling the latency of
323 // a miss (outbound) just as forwardLatency, neglecting the
324 // lookupLatency component.
325 allocateMissBuffer(pkt, forward_time);
326 }
327 }
328}
329
330void
331BaseCache::recvTimingReq(PacketPtr pkt)
332{
333 // anything that is merely forwarded pays for the forward latency and
334 // the delay provided by the crossbar
335 Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
336
337 // We use lookupLatency here because it is used to specify the latency
338 // to access.
339 Cycles lat = lookupLatency;
340 CacheBlk *blk = nullptr;
341 bool satisfied = false;
342 {
343 PacketList writebacks;
344 // Note that lat is passed by reference here. The function
345 // access() calls accessBlock() which can modify lat value.
346 satisfied = access(pkt, blk, lat, writebacks);
347
348 // copy writebacks to write buffer here to ensure they logically
349 // precede anything happening below
350 doWritebacks(writebacks, forward_time);
351 }
352
353 // Here we charge the headerDelay that takes into account the latencies
354 // of the bus, if the packet comes from it.
355 // The latency charged it is just lat that is the value of lookupLatency
356 // modified by access() function, or if not just lookupLatency.
357 // In case of a hit we are neglecting response latency.
358 // In case of a miss we are neglecting forward latency.
359 Tick request_time = clockEdge(lat) + pkt->headerDelay;
360 // Here we reset the timing of the packet.
361 pkt->headerDelay = pkt->payloadDelay = 0;
362 // track time of availability of next prefetch, if any
363 Tick next_pf_time = MaxTick;
364
365 if (satisfied) {
366 // if need to notify the prefetcher we have to do it before
367 // anything else as later handleTimingReqHit might turn the
368 // packet in a response
369 if (prefetcher &&
370 (prefetchOnAccess || (blk && blk->wasPrefetched()))) {
371 if (blk)
372 blk->status &= ~BlkHWPrefetched;
373
374 // Don't notify on SWPrefetch
375 if (!pkt->cmd.isSWPrefetch()) {
376 assert(!pkt->req->isCacheMaintenance());
377 next_pf_time = prefetcher->notify(pkt);
378 }
379 }
380
381 handleTimingReqHit(pkt, blk, request_time);
382 } else {
383 handleTimingReqMiss(pkt, blk, forward_time, request_time);
384
385 // We should call the prefetcher reguardless if the request is
386 // satisfied or not, reguardless if the request is in the MSHR
387 // or not. The request could be a ReadReq hit, but still not
388 // satisfied (potentially because of a prior write to the same
389 // cache line. So, even when not satisfied, there is an MSHR
390 // already allocated for this, we need to let the prefetcher
391 // know about the request
392
393 // Don't notify prefetcher on SWPrefetch or cache maintenance
394 // operations
395 if (prefetcher && pkt &&
396 !pkt->cmd.isSWPrefetch() &&
397 !pkt->req->isCacheMaintenance()) {
398 next_pf_time = prefetcher->notify(pkt);
399 }
400 }
401
402 if (next_pf_time != MaxTick) {
403 schedMemSideSendEvent(next_pf_time);
404 }
405}
406
407void
408BaseCache::handleUncacheableWriteResp(PacketPtr pkt)
409{
410 Tick completion_time = clockEdge(responseLatency) +
411 pkt->headerDelay + pkt->payloadDelay;
412
413 // Reset the bus additional time as it is now accounted for
414 pkt->headerDelay = pkt->payloadDelay = 0;
415
416 cpuSidePort.schedTimingResp(pkt, completion_time, true);
417}
418
419void
420BaseCache::recvTimingResp(PacketPtr pkt)
421{
422 assert(pkt->isResponse());
423
424 // all header delay should be paid for by the crossbar, unless
425 // this is a prefetch response from above
426 panic_if(pkt->headerDelay != 0 && pkt->cmd != MemCmd::HardPFResp,
427 "%s saw a non-zero packet delay\n", name());
428
429 const bool is_error = pkt->isError();
430
431 if (is_error) {
432 DPRINTF(Cache, "%s: Cache received %s with error\n", __func__,
433 pkt->print());
434 }
435
436 DPRINTF(Cache, "%s: Handling response %s\n", __func__,
437 pkt->print());
438
439 // if this is a write, we should be looking at an uncacheable
440 // write
441 if (pkt->isWrite()) {
442 assert(pkt->req->isUncacheable());
443 handleUncacheableWriteResp(pkt);
444 return;
445 }
446
447 // we have dealt with any (uncacheable) writes above, from here on
448 // we know we are dealing with an MSHR due to a miss or a prefetch
449 MSHR *mshr = dynamic_cast<MSHR*>(pkt->popSenderState());
450 assert(mshr);
451
452 if (mshr == noTargetMSHR) {
453 // we always clear at least one target
454 clearBlocked(Blocked_NoTargets);
455 noTargetMSHR = nullptr;
456 }
457
458 // Initial target is used just for stats
459 MSHR::Target *initial_tgt = mshr->getTarget();
460 int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
461 Tick miss_latency = curTick() - initial_tgt->recvTime;
462
463 if (pkt->req->isUncacheable()) {
464 assert(pkt->req->masterId() < system->maxMasters());
465 mshr_uncacheable_lat[stats_cmd_idx][pkt->req->masterId()] +=
466 miss_latency;
467 } else {
468 assert(pkt->req->masterId() < system->maxMasters());
469 mshr_miss_latency[stats_cmd_idx][pkt->req->masterId()] +=
470 miss_latency;
471 }
472
473 PacketList writebacks;
474
475 bool is_fill = !mshr->isForward &&
476 (pkt->isRead() || pkt->cmd == MemCmd::UpgradeResp);
477
478 CacheBlk *blk = tags->findBlock(pkt->getAddr(), pkt->isSecure());
479
480 if (is_fill && !is_error) {
481 DPRINTF(Cache, "Block for addr %#llx being updated in Cache\n",
482 pkt->getAddr());
483
484 blk = handleFill(pkt, blk, writebacks, mshr->allocOnFill());
485 assert(blk != nullptr);
486 }
487
488 if (blk && blk->isValid() && pkt->isClean() && !pkt->isInvalidate()) {
489 // The block was marked not readable while there was a pending
490 // cache maintenance operation, restore its flag.
491 blk->status |= BlkReadable;
492
493 // This was a cache clean operation (without invalidate)
494 // and we have a copy of the block already. Since there
495 // is no invalidation, we can promote targets that don't
496 // require a writable copy
497 mshr->promoteReadable();
498 }
499
500 if (blk && blk->isWritable() && !pkt->req->isCacheInvalidate()) {
501 // If at this point the referenced block is writable and the
502 // response is not a cache invalidate, we promote targets that
503 // were deferred as we couldn't guarrantee a writable copy
504 mshr->promoteWritable();
505 }
506
507 serviceMSHRTargets(mshr, pkt, blk, writebacks);
508
509 if (mshr->promoteDeferredTargets()) {
510 // avoid later read getting stale data while write miss is
511 // outstanding.. see comment in timingAccess()
512 if (blk) {
513 blk->status &= ~BlkReadable;
514 }
515 mshrQueue.markPending(mshr);
516 schedMemSideSendEvent(clockEdge() + pkt->payloadDelay);
517 } else {
518 // while we deallocate an mshr from the queue we still have to
519 // check the isFull condition before and after as we might
520 // have been using the reserved entries already
521 const bool was_full = mshrQueue.isFull();
522 mshrQueue.deallocate(mshr);
523 if (was_full && !mshrQueue.isFull()) {
524 clearBlocked(Blocked_NoMSHRs);
525 }
526
527 // Request the bus for a prefetch if this deallocation freed enough
528 // MSHRs for a prefetch to take place
529 if (prefetcher && mshrQueue.canPrefetch()) {
530 Tick next_pf_time = std::max(prefetcher->nextPrefetchReadyTime(),
531 clockEdge());
532 if (next_pf_time != MaxTick)
533 schedMemSideSendEvent(next_pf_time);
534 }
535 }
536
537 // if we used temp block, check to see if its valid and then clear it out
538 if (blk == tempBlock && tempBlock->isValid()) {
539 evictBlock(blk, writebacks);
540 }
541
542 const Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
543 // copy writebacks to write buffer
544 doWritebacks(writebacks, forward_time);
545
546 DPRINTF(CacheVerbose, "%s: Leaving with %s\n", __func__, pkt->print());
547 delete pkt;
548}
549
550
551Tick
552BaseCache::recvAtomic(PacketPtr pkt)
553{
554 // We are in atomic mode so we pay just for lookupLatency here.
555 Cycles lat = lookupLatency;
556
557 // follow the same flow as in recvTimingReq, and check if a cache
558 // above us is responding
559 if (pkt->cacheResponding() && !pkt->isClean()) {
560 assert(!pkt->req->isCacheInvalidate());
561 DPRINTF(Cache, "Cache above responding to %s: not responding\n",
562 pkt->print());
563
564 // if a cache is responding, and it had the line in Owned
565 // rather than Modified state, we need to invalidate any
566 // copies that are not on the same path to memory
567 assert(pkt->needsWritable() && !pkt->responderHadWritable());
568 lat += ticksToCycles(memSidePort.sendAtomic(pkt));
569
570 return lat * clockPeriod();
571 }
572
573 // should assert here that there are no outstanding MSHRs or
574 // writebacks... that would mean that someone used an atomic
575 // access in timing mode
576
577 CacheBlk *blk = nullptr;
578 PacketList writebacks;
579 bool satisfied = access(pkt, blk, lat, writebacks);
580
581 if (pkt->isClean() && blk && blk->isDirty()) {
582 // A cache clean opearation is looking for a dirty
583 // block. If a dirty block is encountered a WriteClean
584 // will update any copies to the path to the memory
585 // until the point of reference.
586 DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
587 __func__, pkt->print(), blk->print());
588 PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(), pkt->id);
589 writebacks.push_back(wb_pkt);
590 pkt->setSatisfied();
591 }
592
593 // handle writebacks resulting from the access here to ensure they
594 // logically precede anything happening below
595 doWritebacksAtomic(writebacks);
596 assert(writebacks.empty());
597
598 if (!satisfied) {
599 lat += handleAtomicReqMiss(pkt, blk, writebacks);
600 }
601
602 // Note that we don't invoke the prefetcher at all in atomic mode.
603 // It's not clear how to do it properly, particularly for
604 // prefetchers that aggressively generate prefetch candidates and
605 // rely on bandwidth contention to throttle them; these will tend
606 // to pollute the cache in atomic mode since there is no bandwidth
607 // contention. If we ever do want to enable prefetching in atomic
608 // mode, though, this is the place to do it... see timingAccess()
609 // for an example (though we'd want to issue the prefetch(es)
610 // immediately rather than calling requestMemSideBus() as we do
611 // there).
612
613 // do any writebacks resulting from the response handling
614 doWritebacksAtomic(writebacks);
615
616 // if we used temp block, check to see if its valid and if so
617 // clear it out, but only do so after the call to recvAtomic is
618 // finished so that any downstream observers (such as a snoop
619 // filter), first see the fill, and only then see the eviction
620 if (blk == tempBlock && tempBlock->isValid()) {
621 // the atomic CPU calls recvAtomic for fetch and load/store
622 // sequentuially, and we may already have a tempBlock
623 // writeback from the fetch that we have not yet sent
624 if (tempBlockWriteback) {
625 // if that is the case, write the prevoius one back, and
626 // do not schedule any new event
627 writebackTempBlockAtomic();
628 } else {
629 // the writeback/clean eviction happens after the call to
630 // recvAtomic has finished (but before any successive
631 // calls), so that the response handling from the fill is
632 // allowed to happen first
633 schedule(writebackTempBlockAtomicEvent, curTick());
634 }
635
636 tempBlockWriteback = evictBlock(blk);
637 }
638
639 if (pkt->needsResponse()) {
640 pkt->makeAtomicResponse();
641 }
642
643 return lat * clockPeriod();
644}
645
646void
647BaseCache::functionalAccess(PacketPtr pkt, bool from_cpu_side)
648{
649 Addr blk_addr = pkt->getBlockAddr(blkSize);
650 bool is_secure = pkt->isSecure();
651 CacheBlk *blk = tags->findBlock(pkt->getAddr(), is_secure);
652 MSHR *mshr = mshrQueue.findMatch(blk_addr, is_secure);
653
654 pkt->pushLabel(name());
655
656 CacheBlkPrintWrapper cbpw(blk);
657
658 // Note that just because an L2/L3 has valid data doesn't mean an
659 // L1 doesn't have a more up-to-date modified copy that still
660 // needs to be found. As a result we always update the request if
661 // we have it, but only declare it satisfied if we are the owner.
662
663 // see if we have data at all (owned or otherwise)
664 bool have_data = blk && blk->isValid()
665 && pkt->trySatisfyFunctional(&cbpw, blk_addr, is_secure, blkSize,
666 blk->data);
667
668 // data we have is dirty if marked as such or if we have an
669 // in-service MSHR that is pending a modified line
670 bool have_dirty =
671 have_data && (blk->isDirty() ||
672 (mshr && mshr->inService && mshr->isPendingModified()));
673
674 bool done = have_dirty ||
675 cpuSidePort.trySatisfyFunctional(pkt) ||
676 mshrQueue.trySatisfyFunctional(pkt, blk_addr) ||
677 writeBuffer.trySatisfyFunctional(pkt, blk_addr) ||
678 memSidePort.trySatisfyFunctional(pkt);
679
680 DPRINTF(CacheVerbose, "%s: %s %s%s%s\n", __func__, pkt->print(),
681 (blk && blk->isValid()) ? "valid " : "",
682 have_data ? "data " : "", done ? "done " : "");
683
684 // We're leaving the cache, so pop cache->name() label
685 pkt->popLabel();
686
687 if (done) {
688 pkt->makeResponse();
689 } else {
690 // if it came as a request from the CPU side then make sure it
691 // continues towards the memory side
692 if (from_cpu_side) {
693 memSidePort.sendFunctional(pkt);
694 } else if (cpuSidePort.isSnooping()) {
695 // if it came from the memory side, it must be a snoop request
696 // and we should only forward it if we are forwarding snoops
697 cpuSidePort.sendFunctionalSnoop(pkt);
698 }
699 }
700}
701
702
703void
704BaseCache::cmpAndSwap(CacheBlk *blk, PacketPtr pkt)
705{
706 assert(pkt->isRequest());
707
708 uint64_t overwrite_val;
709 bool overwrite_mem;
710 uint64_t condition_val64;
711 uint32_t condition_val32;
712
713 int offset = pkt->getOffset(blkSize);
714 uint8_t *blk_data = blk->data + offset;
715
716 assert(sizeof(uint64_t) >= pkt->getSize());
717
718 overwrite_mem = true;
719 // keep a copy of our possible write value, and copy what is at the
720 // memory address into the packet
721 pkt->writeData((uint8_t *)&overwrite_val);
722 pkt->setData(blk_data);
723
724 if (pkt->req->isCondSwap()) {
725 if (pkt->getSize() == sizeof(uint64_t)) {
726 condition_val64 = pkt->req->getExtraData();
727 overwrite_mem = !std::memcmp(&condition_val64, blk_data,
728 sizeof(uint64_t));
729 } else if (pkt->getSize() == sizeof(uint32_t)) {
730 condition_val32 = (uint32_t)pkt->req->getExtraData();
731 overwrite_mem = !std::memcmp(&condition_val32, blk_data,
732 sizeof(uint32_t));
733 } else
734 panic("Invalid size for conditional read/write\n");
735 }
736
737 if (overwrite_mem) {
738 std::memcpy(blk_data, &overwrite_val, pkt->getSize());
739 blk->status |= BlkDirty;
740 }
741}
742
743QueueEntry*
744BaseCache::getNextQueueEntry()
745{
746 // Check both MSHR queue and write buffer for potential requests,
747 // note that null does not mean there is no request, it could
748 // simply be that it is not ready
749 MSHR *miss_mshr = mshrQueue.getNext();
750 WriteQueueEntry *wq_entry = writeBuffer.getNext();
751
752 // If we got a write buffer request ready, first priority is a
753 // full write buffer, otherwise we favour the miss requests
754 if (wq_entry && (writeBuffer.isFull() || !miss_mshr)) {
755 // need to search MSHR queue for conflicting earlier miss.
756 MSHR *conflict_mshr =
757 mshrQueue.findPending(wq_entry->blkAddr,
758 wq_entry->isSecure);
759
760 if (conflict_mshr && conflict_mshr->order < wq_entry->order) {
761 // Service misses in order until conflict is cleared.
762 return conflict_mshr;
763
764 // @todo Note that we ignore the ready time of the conflict here
765 }
766
767 // No conflicts; issue write
768 return wq_entry;
769 } else if (miss_mshr) {
770 // need to check for conflicting earlier writeback
771 WriteQueueEntry *conflict_mshr =
772 writeBuffer.findPending(miss_mshr->blkAddr,
773 miss_mshr->isSecure);
774 if (conflict_mshr) {
775 // not sure why we don't check order here... it was in the
776 // original code but commented out.
777
778 // The only way this happens is if we are
779 // doing a write and we didn't have permissions
780 // then subsequently saw a writeback (owned got evicted)
781 // We need to make sure to perform the writeback first
782 // To preserve the dirty data, then we can issue the write
783
784 // should we return wq_entry here instead? I.e. do we
785 // have to flush writes in order? I don't think so... not
786 // for Alpha anyway. Maybe for x86?
787 return conflict_mshr;
788
789 // @todo Note that we ignore the ready time of the conflict here
790 }
791
792 // No conflicts; issue read
793 return miss_mshr;
794 }
795
796 // fall through... no pending requests. Try a prefetch.
797 assert(!miss_mshr && !wq_entry);
798 if (prefetcher && mshrQueue.canPrefetch()) {
799 // If we have a miss queue slot, we can try a prefetch
800 PacketPtr pkt = prefetcher->getPacket();
801 if (pkt) {
802 Addr pf_addr = pkt->getBlockAddr(blkSize);
803 if (!tags->findBlock(pf_addr, pkt->isSecure()) &&
804 !mshrQueue.findMatch(pf_addr, pkt->isSecure()) &&
805 !writeBuffer.findMatch(pf_addr, pkt->isSecure())) {
806 // Update statistic on number of prefetches issued
807 // (hwpf_mshr_misses)
808 assert(pkt->req->masterId() < system->maxMasters());
809 mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
810
811 // allocate an MSHR and return it, note
812 // that we send the packet straight away, so do not
813 // schedule the send
814 return allocateMissBuffer(pkt, curTick(), false);
815 } else {
816 // free the request and packet
817 delete pkt;
818 }
819 }
820 }
821
822 return nullptr;
823}
824
825void
826BaseCache::satisfyRequest(PacketPtr pkt, CacheBlk *blk, bool, bool)
827{
828 assert(pkt->isRequest());
829
830 assert(blk && blk->isValid());
831 // Occasionally this is not true... if we are a lower-level cache
832 // satisfying a string of Read and ReadEx requests from
833 // upper-level caches, a Read will mark the block as shared but we
834 // can satisfy a following ReadEx anyway since we can rely on the
835 // Read requester(s) to have buffered the ReadEx snoop and to
836 // invalidate their blocks after receiving them.
837 // assert(!pkt->needsWritable() || blk->isWritable());
838 assert(pkt->getOffset(blkSize) + pkt->getSize() <= blkSize);
839
840 // Check RMW operations first since both isRead() and
841 // isWrite() will be true for them
842 if (pkt->cmd == MemCmd::SwapReq) {
843 if (pkt->isAtomicOp()) {
844 // extract data from cache and save it into the data field in
845 // the packet as a return value from this atomic op
846
847 int offset = tags->extractBlkOffset(pkt->getAddr());
848 uint8_t *blk_data = blk->data + offset;
849 std::memcpy(pkt->getPtr<uint8_t>(), blk_data, pkt->getSize());
850
851 // execute AMO operation
852 (*(pkt->getAtomicOp()))(blk_data);
853
854 // set block status to dirty
855 blk->status |= BlkDirty;
856 } else {
857 cmpAndSwap(blk, pkt);
858 }
859 } else if (pkt->isWrite()) {
860 // we have the block in a writable state and can go ahead,
861 // note that the line may be also be considered writable in
862 // downstream caches along the path to memory, but always
863 // Exclusive, and never Modified
864 assert(blk->isWritable());
865 // Write or WriteLine at the first cache with block in writable state
866 if (blk->checkWrite(pkt)) {
867 pkt->writeDataToBlock(blk->data, blkSize);
868 }
869 // Always mark the line as dirty (and thus transition to the
870 // Modified state) even if we are a failed StoreCond so we
871 // supply data to any snoops that have appended themselves to
872 // this cache before knowing the store will fail.
873 blk->status |= BlkDirty;
874 DPRINTF(CacheVerbose, "%s for %s (write)\n", __func__, pkt->print());
875 } else if (pkt->isRead()) {
876 if (pkt->isLLSC()) {
877 blk->trackLoadLocked(pkt);
878 }
879
880 // all read responses have a data payload
881 assert(pkt->hasRespData());
882 pkt->setDataFromBlock(blk->data, blkSize);
883 } else if (pkt->isUpgrade()) {
884 // sanity check
885 assert(!pkt->hasSharers());
886
887 if (blk->isDirty()) {
888 // we were in the Owned state, and a cache above us that
889 // has the line in Shared state needs to be made aware
890 // that the data it already has is in fact dirty
891 pkt->setCacheResponding();
892 blk->status &= ~BlkDirty;
893 }
894 } else if (pkt->isClean()) {
895 blk->status &= ~BlkDirty;
896 } else {
897 assert(pkt->isInvalidate());
898 invalidateBlock(blk);
899 DPRINTF(CacheVerbose, "%s for %s (invalidation)\n", __func__,
900 pkt->print());
901 }
902}
903
904/////////////////////////////////////////////////////
905//
906// Access path: requests coming in from the CPU side
907//
908/////////////////////////////////////////////////////
909
910bool
911BaseCache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
912 PacketList &writebacks)
913{
914 // sanity check
915 assert(pkt->isRequest());
916
917 chatty_assert(!(isReadOnly && pkt->isWrite()),
918 "Should never see a write in a read-only cache %s\n",
919 name());
920
921 // Here lat is the value passed as parameter to accessBlock() function
922 // that can modify its value.
923 blk = tags->accessBlock(pkt->getAddr(), pkt->isSecure(), lat);
924
925 DPRINTF(Cache, "%s for %s %s\n", __func__, pkt->print(),
926 blk ? "hit " + blk->print() : "miss");
927
928 if (pkt->req->isCacheMaintenance()) {
929 // A cache maintenance operation is always forwarded to the
930 // memory below even if the block is found in dirty state.
931
932 // We defer any changes to the state of the block until we
933 // create and mark as in service the mshr for the downstream
934 // packet.
935 return false;
936 }
937
938 if (pkt->isEviction()) {
939 // We check for presence of block in above caches before issuing
940 // Writeback or CleanEvict to write buffer. Therefore the only
941 // possible cases can be of a CleanEvict packet coming from above
942 // encountering a Writeback generated in this cache peer cache and
943 // waiting in the write buffer. Cases of upper level peer caches
944 // generating CleanEvict and Writeback or simply CleanEvict and
945 // CleanEvict almost simultaneously will be caught by snoops sent out
946 // by crossbar.
947 WriteQueueEntry *wb_entry = writeBuffer.findMatch(pkt->getAddr(),
948 pkt->isSecure());
949 if (wb_entry) {
950 assert(wb_entry->getNumTargets() == 1);
951 PacketPtr wbPkt = wb_entry->getTarget()->pkt;
952 assert(wbPkt->isWriteback());
953
954 if (pkt->isCleanEviction()) {
955 // The CleanEvict and WritebackClean snoops into other
956 // peer caches of the same level while traversing the
957 // crossbar. If a copy of the block is found, the
958 // packet is deleted in the crossbar. Hence, none of
959 // the other upper level caches connected to this
960 // cache have the block, so we can clear the
961 // BLOCK_CACHED flag in the Writeback if set and
962 // discard the CleanEvict by returning true.
963 wbPkt->clearBlockCached();
964 return true;
965 } else {
966 assert(pkt->cmd == MemCmd::WritebackDirty);
967 // Dirty writeback from above trumps our clean
968 // writeback... discard here
969 // Note: markInService will remove entry from writeback buffer.
970 markInService(wb_entry);
971 delete wbPkt;
972 }
973 }
974 }
975
976 // Writeback handling is special case. We can write the block into
977 // the cache without having a writeable copy (or any copy at all).
978 if (pkt->isWriteback()) {
979 assert(blkSize == pkt->getSize());
980
981 // we could get a clean writeback while we are having
982 // outstanding accesses to a block, do the simple thing for
983 // now and drop the clean writeback so that we do not upset
984 // any ordering/decisions about ownership already taken
985 if (pkt->cmd == MemCmd::WritebackClean &&
986 mshrQueue.findMatch(pkt->getAddr(), pkt->isSecure())) {
987 DPRINTF(Cache, "Clean writeback %#llx to block with MSHR, "
988 "dropping\n", pkt->getAddr());
989 return true;
990 }
991
992 if (!blk) {
993 // need to do a replacement
994 blk = allocateBlock(pkt, writebacks);
995 if (!blk) {
996 // no replaceable block available: give up, fwd to next level.
997 incMissCount(pkt);
998 return false;
999 }
1000
1001 blk->status |= (BlkValid | BlkReadable);
1002 }
1003 // only mark the block dirty if we got a writeback command,
1004 // and leave it as is for a clean writeback
1005 if (pkt->cmd == MemCmd::WritebackDirty) {
1006 // TODO: the coherent cache can assert(!blk->isDirty());
1007 blk->status |= BlkDirty;
1008 }
1009 // if the packet does not have sharers, it is passing
1010 // writable, and we got the writeback in Modified or Exclusive
1011 // state, if not we are in the Owned or Shared state
1012 if (!pkt->hasSharers()) {
1013 blk->status |= BlkWritable;
1014 }
1015 // nothing else to do; writeback doesn't expect response
1016 assert(!pkt->needsResponse());
1017 pkt->writeDataToBlock(blk->data, blkSize);
1018 DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1019 incHitCount(pkt);
1020 // populate the time when the block will be ready to access.
1021 blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1022 pkt->payloadDelay;
1023 return true;
1024 } else if (pkt->cmd == MemCmd::CleanEvict) {
1025 if (blk) {
1026 // Found the block in the tags, need to stop CleanEvict from
1027 // propagating further down the hierarchy. Returning true will
1028 // treat the CleanEvict like a satisfied write request and delete
1029 // it.
1030 return true;
1031 }
1032 // We didn't find the block here, propagate the CleanEvict further
1033 // down the memory hierarchy. Returning false will treat the CleanEvict
1034 // like a Writeback which could not find a replaceable block so has to
1035 // go to next level.
1036 return false;
1037 } else if (pkt->cmd == MemCmd::WriteClean) {
1038 // WriteClean handling is a special case. We can allocate a
1039 // block directly if it doesn't exist and we can update the
1040 // block immediately. The WriteClean transfers the ownership
1041 // of the block as well.
1042 assert(blkSize == pkt->getSize());
1043
1044 if (!blk) {
1045 if (pkt->writeThrough()) {
1046 // if this is a write through packet, we don't try to
1047 // allocate if the block is not present
1048 return false;
1049 } else {
1050 // a writeback that misses needs to allocate a new block
1051 blk = allocateBlock(pkt, writebacks);
1052 if (!blk) {
1053 // no replaceable block available: give up, fwd to
1054 // next level.
1055 incMissCount(pkt);
1056 return false;
1057 }
1058
1059 blk->status |= (BlkValid | BlkReadable);
1060 }
1061 }
1062
1063 // at this point either this is a writeback or a write-through
1064 // write clean operation and the block is already in this
1065 // cache, we need to update the data and the block flags
1066 assert(blk);
1067 // TODO: the coherent cache can assert(!blk->isDirty());
1068 if (!pkt->writeThrough()) {
1069 blk->status |= BlkDirty;
1070 }
1071 // nothing else to do; writeback doesn't expect response
1072 assert(!pkt->needsResponse());
1073 pkt->writeDataToBlock(blk->data, blkSize);
1074 DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1075
1076 incHitCount(pkt);
1077 // populate the time when the block will be ready to access.
1078 blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1079 pkt->payloadDelay;
1080 // if this a write-through packet it will be sent to cache
1081 // below
1082 return !pkt->writeThrough();
1083 } else if (blk && (pkt->needsWritable() ? blk->isWritable() :
1084 blk->isReadable())) {
1085 // OK to satisfy access
1086 incHitCount(pkt);
1087 satisfyRequest(pkt, blk);
1088 maintainClusivity(pkt->fromCache(), blk);
1089
1090 return true;
1091 }
1092
1093 // Can't satisfy access normally... either no block (blk == nullptr)
1094 // or have block but need writable
1095
1096 incMissCount(pkt);
1097
1098 if (!blk && pkt->isLLSC() && pkt->isWrite()) {
1099 // complete miss on store conditional... just give up now
1100 pkt->req->setExtraData(0);
1101 return true;
1102 }
1103
1104 return false;
1105}
1106
1107void
1108BaseCache::maintainClusivity(bool from_cache, CacheBlk *blk)
1109{
1110 if (from_cache && blk && blk->isValid() && !blk->isDirty() &&
1111 clusivity == Enums::mostly_excl) {
1112 // if we have responded to a cache, and our block is still
1113 // valid, but not dirty, and this cache is mostly exclusive
1114 // with respect to the cache above, drop the block
1115 invalidateBlock(blk);
1116 }
1117}
1118
1119CacheBlk*
1120BaseCache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks,
1121 bool allocate)
1122{
1123 assert(pkt->isResponse() || pkt->cmd == MemCmd::WriteLineReq);
1124 Addr addr = pkt->getAddr();
1125 bool is_secure = pkt->isSecure();
1126#if TRACING_ON
1127 CacheBlk::State old_state = blk ? blk->status : 0;
1128#endif
1129
1130 // When handling a fill, we should have no writes to this line.
1131 assert(addr == pkt->getBlockAddr(blkSize));
1132 assert(!writeBuffer.findMatch(addr, is_secure));
1133
1134 if (!blk) {
1135 // better have read new data...
1136 assert(pkt->hasData());
1137
1138 // only read responses and write-line requests have data;
1139 // note that we don't write the data here for write-line - that
1140 // happens in the subsequent call to satisfyRequest
1141 assert(pkt->isRead() || pkt->cmd == MemCmd::WriteLineReq);
1142
1143 // need to do a replacement if allocating, otherwise we stick
1144 // with the temporary storage
1145 blk = allocate ? allocateBlock(pkt, writebacks) : nullptr;
1146
1147 if (!blk) {
1148 // No replaceable block or a mostly exclusive
1149 // cache... just use temporary storage to complete the
1150 // current request and then get rid of it
1151 assert(!tempBlock->isValid());
1152 blk = tempBlock;
1153 tempBlock->insert(addr, is_secure);
1154 DPRINTF(Cache, "using temp block for %#llx (%s)\n", addr,
1155 is_secure ? "s" : "ns");
1156 }
1157
1158 // we should never be overwriting a valid block
1159 assert(!blk->isValid());
1160 } else {
1161 // existing block... probably an upgrade
1162 assert(regenerateBlkAddr(blk) == addr);
1163 assert(blk->isSecure() == is_secure);
1164 // either we're getting new data or the block should already be valid
1165 assert(pkt->hasData() || blk->isValid());
1166 // don't clear block status... if block is already dirty we
1167 // don't want to lose that
1168 }
1169
1170 blk->status |= BlkValid | BlkReadable;
1171
1172 // sanity check for whole-line writes, which should always be
1173 // marked as writable as part of the fill, and then later marked
1174 // dirty as part of satisfyRequest
1175 if (pkt->cmd == MemCmd::WriteLineReq) {
1176 assert(!pkt->hasSharers());
1177 }
1178
1179 // here we deal with setting the appropriate state of the line,
1180 // and we start by looking at the hasSharers flag, and ignore the
1181 // cacheResponding flag (normally signalling dirty data) if the
1182 // packet has sharers, thus the line is never allocated as Owned
1183 // (dirty but not writable), and always ends up being either
1184 // Shared, Exclusive or Modified, see Packet::setCacheResponding
1185 // for more details
1186 if (!pkt->hasSharers()) {
1187 // we could get a writable line from memory (rather than a
1188 // cache) even in a read-only cache, note that we set this bit
1189 // even for a read-only cache, possibly revisit this decision
1190 blk->status |= BlkWritable;
1191
1192 // check if we got this via cache-to-cache transfer (i.e., from a
1193 // cache that had the block in Modified or Owned state)
1194 if (pkt->cacheResponding()) {
1195 // we got the block in Modified state, and invalidated the
1196 // owners copy
1197 blk->status |= BlkDirty;
1198
1199 chatty_assert(!isReadOnly, "Should never see dirty snoop response "
1200 "in read-only cache %s\n", name());
1201 }
1202 }
1203
1204 DPRINTF(Cache, "Block addr %#llx (%s) moving from state %x to %s\n",
1205 addr, is_secure ? "s" : "ns", old_state, blk->print());
1206
1207 // if we got new data, copy it in (checking for a read response
1208 // and a response that has data is the same in the end)
1209 if (pkt->isRead()) {
1210 // sanity checks
1211 assert(pkt->hasData());
1212 assert(pkt->getSize() == blkSize);
1213
1214 pkt->writeDataToBlock(blk->data, blkSize);
1215 }
1216 // We pay for fillLatency here.
1217 blk->whenReady = clockEdge() + fillLatency * clockPeriod() +
1218 pkt->payloadDelay;
1219
1220 return blk;
1221}
1222
1223CacheBlk*
1224BaseCache::allocateBlock(const PacketPtr pkt, PacketList &writebacks)
1225{
1226 // Get address
1227 const Addr addr = pkt->getAddr();
1228
1229 // Get secure bit
1230 const bool is_secure = pkt->isSecure();
1231
1232 // Find replacement victim
1233 std::vector<CacheBlk*> evict_blks;
1234 CacheBlk *victim = tags->findVictim(addr, is_secure, evict_blks);
1235
1236 // It is valid to return nullptr if there is no victim
1237 if (!victim)
1238 return nullptr;
1239
1240 // Check for transient state allocations. If any of the entries listed
1241 // for eviction has a transient state, the allocation fails
1242 for (const auto& blk : evict_blks) {
1243 if (blk->isValid()) {
1244 Addr repl_addr = regenerateBlkAddr(blk);
1245 MSHR *repl_mshr = mshrQueue.findMatch(repl_addr, blk->isSecure());
1246 if (repl_mshr) {
1247 // must be an outstanding upgrade or clean request
1248 // on a block we're about to replace...
1249 assert((!blk->isWritable() && repl_mshr->needsWritable()) ||
1250 repl_mshr->isCleaning());
1251
1252 // too hard to replace block with transient state
1253 // allocation failed, block not inserted
1254 return nullptr;
1255 }
1256 }
1257 }
1258
1259 // The victim will be replaced by a new entry, so increase the replacement
1260 // counter if a valid block is being replaced
1261 if (victim->isValid()) {
1262 DPRINTF(Cache, "replacement: replacing %#llx (%s) with %#llx "
1263 "(%s): %s\n", regenerateBlkAddr(victim),
1264 victim->isSecure() ? "s" : "ns",
1265 addr, is_secure ? "s" : "ns",
1266 victim->isDirty() ? "writeback" : "clean");
1267
1268 replacements++;
1269 }
1270
1271 // Evict valid blocks associated to this victim block
1272 for (const auto& blk : evict_blks) {
1273 if (blk->isValid()) {
1274 if (blk->wasPrefetched()) {
1275 unusedPrefetches++;
1276 }
1277
1278 evictBlock(blk, writebacks);
1279 }
1280 }
1281
1282 // Insert new block at victimized entry
1283 tags->insertBlock(pkt, victim);
1284
1285 return victim;
1286}
1287
1288void
1289BaseCache::invalidateBlock(CacheBlk *blk)
1290{
1291 if (blk != tempBlock)
1292 tags->invalidate(blk);
1293 blk->invalidate();
1294}
1295
1296PacketPtr
1297BaseCache::writebackBlk(CacheBlk *blk)
1298{
1299 chatty_assert(!isReadOnly || writebackClean,
1300 "Writeback from read-only cache");
1301 assert(blk && blk->isValid() && (blk->isDirty() || writebackClean));
1302
1303 writebacks[Request::wbMasterId]++;
1304
1305 RequestPtr req = std::make_shared<Request>(
1306 regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1307
1308 if (blk->isSecure())
1309 req->setFlags(Request::SECURE);
1310
1311 req->taskId(blk->task_id);
1312
1313 PacketPtr pkt =
1314 new Packet(req, blk->isDirty() ?
1315 MemCmd::WritebackDirty : MemCmd::WritebackClean);
1316
1317 DPRINTF(Cache, "Create Writeback %s writable: %d, dirty: %d\n",
1318 pkt->print(), blk->isWritable(), blk->isDirty());
1319
1320 if (blk->isWritable()) {
1321 // not asserting shared means we pass the block in modified
1322 // state, mark our own block non-writeable
1323 blk->status &= ~BlkWritable;
1324 } else {
1325 // we are in the Owned state, tell the receiver
1326 pkt->setHasSharers();
1327 }
1328
1329 // make sure the block is not marked dirty
1330 blk->status &= ~BlkDirty;
1331
1332 pkt->allocate();
1333 pkt->setDataFromBlock(blk->data, blkSize);
1334
1335 return pkt;
1336}
1337
1338PacketPtr
1339BaseCache::writecleanBlk(CacheBlk *blk, Request::Flags dest, PacketId id)
1340{
1341 RequestPtr req = std::make_shared<Request>(
1342 regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1343
1344 if (blk->isSecure()) {
1345 req->setFlags(Request::SECURE);
1346 }
1347 req->taskId(blk->task_id);
1348
1349 PacketPtr pkt = new Packet(req, MemCmd::WriteClean, blkSize, id);
1350
1351 if (dest) {
1352 req->setFlags(dest);
1353 pkt->setWriteThrough();
1354 }
1355
1356 DPRINTF(Cache, "Create %s writable: %d, dirty: %d\n", pkt->print(),
1357 blk->isWritable(), blk->isDirty());
1358
1359 if (blk->isWritable()) {
1360 // not asserting shared means we pass the block in modified
1361 // state, mark our own block non-writeable
1362 blk->status &= ~BlkWritable;
1363 } else {
1364 // we are in the Owned state, tell the receiver
1365 pkt->setHasSharers();
1366 }
1367
1368 // make sure the block is not marked dirty
1369 blk->status &= ~BlkDirty;
1370
1371 pkt->allocate();
1372 pkt->setDataFromBlock(blk->data, blkSize);
1373
1374 return pkt;
1375}
1376
1377
1378void
1379BaseCache::memWriteback()
1380{
1381 tags->forEachBlk([this](CacheBlk &blk) { writebackVisitor(blk); });
1382}
1383
1384void
1385BaseCache::memInvalidate()
1386{
1387 tags->forEachBlk([this](CacheBlk &blk) { invalidateVisitor(blk); });
1388}
1389
1390bool
1391BaseCache::isDirty() const
1392{
1393 return tags->anyBlk([](CacheBlk &blk) { return blk.isDirty(); });
1394}
1395
1396void
1397BaseCache::writebackVisitor(CacheBlk &blk)
1398{
1399 if (blk.isDirty()) {
1400 assert(blk.isValid());
1401
1402 RequestPtr request = std::make_shared<Request>(
1403 regenerateBlkAddr(&blk), blkSize, 0, Request::funcMasterId);
1404
1405 request->taskId(blk.task_id);
1406 if (blk.isSecure()) {
1407 request->setFlags(Request::SECURE);
1408 }
1409
1410 Packet packet(request, MemCmd::WriteReq);
1411 packet.dataStatic(blk.data);
1412
1413 memSidePort.sendFunctional(&packet);
1414
1415 blk.status &= ~BlkDirty;
1416 }
1417}
1418
1419void
1420BaseCache::invalidateVisitor(CacheBlk &blk)
1421{
1422 if (blk.isDirty())
1423 warn_once("Invalidating dirty cache lines. " \
1424 "Expect things to break.\n");
1425
1426 if (blk.isValid()) {
1427 assert(!blk.isDirty());
1428 invalidateBlock(&blk);
1429 }
1430}
1431
1432Tick
1433BaseCache::nextQueueReadyTime() const
1434{
1435 Tick nextReady = std::min(mshrQueue.nextReadyTime(),
1436 writeBuffer.nextReadyTime());
1437
1438 // Don't signal prefetch ready time if no MSHRs available
1439 // Will signal once enoguh MSHRs are deallocated
1440 if (prefetcher && mshrQueue.canPrefetch()) {
1441 nextReady = std::min(nextReady,
1442 prefetcher->nextPrefetchReadyTime());
1443 }
1444
1445 return nextReady;
1446}
1447
1448
1449bool
1450BaseCache::sendMSHRQueuePacket(MSHR* mshr)
1451{
1452 assert(mshr);
1453
1454 // use request from 1st target
1455 PacketPtr tgt_pkt = mshr->getTarget()->pkt;
1456
1457 DPRINTF(Cache, "%s: MSHR %s\n", __func__, tgt_pkt->print());
1458
1459 CacheBlk *blk = tags->findBlock(mshr->blkAddr, mshr->isSecure);
1460
1461 // either a prefetch that is not present upstream, or a normal
1462 // MSHR request, proceed to get the packet to send downstream
1463 PacketPtr pkt = createMissPacket(tgt_pkt, blk, mshr->needsWritable());
1464
1465 mshr->isForward = (pkt == nullptr);
1466
1467 if (mshr->isForward) {
1468 // not a cache block request, but a response is expected
1469 // make copy of current packet to forward, keep current
1470 // copy for response handling
1471 pkt = new Packet(tgt_pkt, false, true);
1472 assert(!pkt->isWrite());
1473 }
1474
1475 // play it safe and append (rather than set) the sender state,
1476 // as forwarded packets may already have existing state
1477 pkt->pushSenderState(mshr);
1478
1479 if (pkt->isClean() && blk && blk->isDirty()) {
1480 // A cache clean opearation is looking for a dirty block. Mark
1481 // the packet so that the destination xbar can determine that
1482 // there will be a follow-up write packet as well.
1483 pkt->setSatisfied();
1484 }
1485
1486 if (!memSidePort.sendTimingReq(pkt)) {
1487 // we are awaiting a retry, but we
1488 // delete the packet and will be creating a new packet
1489 // when we get the opportunity
1490 delete pkt;
1491
1492 // note that we have now masked any requestBus and
1493 // schedSendEvent (we will wait for a retry before
1494 // doing anything), and this is so even if we do not
1495 // care about this packet and might override it before
1496 // it gets retried
1497 return true;
1498 } else {
1499 // As part of the call to sendTimingReq the packet is
1500 // forwarded to all neighbouring caches (and any caches
1501 // above them) as a snoop. Thus at this point we know if
1502 // any of the neighbouring caches are responding, and if
1503 // so, we know it is dirty, and we can determine if it is
1504 // being passed as Modified, making our MSHR the ordering
1505 // point
1506 bool pending_modified_resp = !pkt->hasSharers() &&
1507 pkt->cacheResponding();
1508 markInService(mshr, pending_modified_resp);
1509
1510 if (pkt->isClean() && blk && blk->isDirty()) {
1511 // A cache clean opearation is looking for a dirty
1512 // block. If a dirty block is encountered a WriteClean
1513 // will update any copies to the path to the memory
1514 // until the point of reference.
1515 DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
1516 __func__, pkt->print(), blk->print());
1517 PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(),
1518 pkt->id);
1519 PacketList writebacks;
1520 writebacks.push_back(wb_pkt);
1521 doWritebacks(writebacks, 0);
1522 }
1523
1524 return false;
1525 }
1526}
1527
1528bool
1529BaseCache::sendWriteQueuePacket(WriteQueueEntry* wq_entry)
1530{
1531 assert(wq_entry);
1532
1533 // always a single target for write queue entries
1534 PacketPtr tgt_pkt = wq_entry->getTarget()->pkt;
1535
1536 DPRINTF(Cache, "%s: write %s\n", __func__, tgt_pkt->print());
1537
1538 // forward as is, both for evictions and uncacheable writes
1539 if (!memSidePort.sendTimingReq(tgt_pkt)) {
1540 // note that we have now masked any requestBus and
1541 // schedSendEvent (we will wait for a retry before
1542 // doing anything), and this is so even if we do not
1543 // care about this packet and might override it before
1544 // it gets retried
1545 return true;
1546 } else {
1547 markInService(wq_entry);
1548 return false;
1549 }
1550}
1551
1552void
1553BaseCache::serialize(CheckpointOut &cp) const
1554{
1555 bool dirty(isDirty());
1556
1557 if (dirty) {
1558 warn("*** The cache still contains dirty data. ***\n");
1559 warn(" Make sure to drain the system using the correct flags.\n");
1560 warn(" This checkpoint will not restore correctly " \
1561 "and dirty data in the cache will be lost!\n");
1562 }
1563
1564 // Since we don't checkpoint the data in the cache, any dirty data
1565 // will be lost when restoring from a checkpoint of a system that
1566 // wasn't drained properly. Flag the checkpoint as invalid if the
1567 // cache contains dirty data.
1568 bool bad_checkpoint(dirty);
1569 SERIALIZE_SCALAR(bad_checkpoint);
1570}
1571
1572void
1573BaseCache::unserialize(CheckpointIn &cp)
1574{
1575 bool bad_checkpoint;
1576 UNSERIALIZE_SCALAR(bad_checkpoint);
1577 if (bad_checkpoint) {
1578 fatal("Restoring from checkpoints with dirty caches is not "
1579 "supported in the classic memory system. Please remove any "
1580 "caches or drain them properly before taking checkpoints.\n");
1581 }
1582}
1583
1584void
1585BaseCache::regStats()
1586{
1587 MemObject::regStats();
1588
1589 using namespace Stats;
1590
1591 // Hit statistics
1592 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1593 MemCmd cmd(access_idx);
1594 const string &cstr = cmd.toString();
1595
1596 hits[access_idx]
1597 .init(system->maxMasters())
1598 .name(name() + "." + cstr + "_hits")
1599 .desc("number of " + cstr + " hits")
1600 .flags(total | nozero | nonan)
1601 ;
1602 for (int i = 0; i < system->maxMasters(); i++) {
1603 hits[access_idx].subname(i, system->getMasterName(i));
1604 }
1605 }
1606
1607// These macros make it easier to sum the right subset of commands and
1608// to change the subset of commands that are considered "demand" vs
1609// "non-demand"
1610#define SUM_DEMAND(s) \
1611 (s[MemCmd::ReadReq] + s[MemCmd::WriteReq] + s[MemCmd::WriteLineReq] + \
1612 s[MemCmd::ReadExReq] + s[MemCmd::ReadCleanReq] + s[MemCmd::ReadSharedReq])
1613
1614// should writebacks be included here? prior code was inconsistent...
1615#define SUM_NON_DEMAND(s) \
1616 (s[MemCmd::SoftPFReq] + s[MemCmd::HardPFReq])
1617
1618 demandHits
1619 .name(name() + ".demand_hits")
1620 .desc("number of demand (read+write) hits")
1621 .flags(total | nozero | nonan)
1622 ;
1623 demandHits = SUM_DEMAND(hits);
1624 for (int i = 0; i < system->maxMasters(); i++) {
1625 demandHits.subname(i, system->getMasterName(i));
1626 }
1627
1628 overallHits
1629 .name(name() + ".overall_hits")
1630 .desc("number of overall hits")
1631 .flags(total | nozero | nonan)
1632 ;
1633 overallHits = demandHits + SUM_NON_DEMAND(hits);
1634 for (int i = 0; i < system->maxMasters(); i++) {
1635 overallHits.subname(i, system->getMasterName(i));
1636 }
1637
1638 // Miss statistics
1639 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1640 MemCmd cmd(access_idx);
1641 const string &cstr = cmd.toString();
1642
1643 misses[access_idx]
1644 .init(system->maxMasters())
1645 .name(name() + "." + cstr + "_misses")
1646 .desc("number of " + cstr + " misses")
1647 .flags(total | nozero | nonan)
1648 ;
1649 for (int i = 0; i < system->maxMasters(); i++) {
1650 misses[access_idx].subname(i, system->getMasterName(i));
1651 }
1652 }
1653
1654 demandMisses
1655 .name(name() + ".demand_misses")
1656 .desc("number of demand (read+write) misses")
1657 .flags(total | nozero | nonan)
1658 ;
1659 demandMisses = SUM_DEMAND(misses);
1660 for (int i = 0; i < system->maxMasters(); i++) {
1661 demandMisses.subname(i, system->getMasterName(i));
1662 }
1663
1664 overallMisses
1665 .name(name() + ".overall_misses")
1666 .desc("number of overall misses")
1667 .flags(total | nozero | nonan)
1668 ;
1669 overallMisses = demandMisses + SUM_NON_DEMAND(misses);
1670 for (int i = 0; i < system->maxMasters(); i++) {
1671 overallMisses.subname(i, system->getMasterName(i));
1672 }
1673
1674 // Miss latency statistics
1675 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1676 MemCmd cmd(access_idx);
1677 const string &cstr = cmd.toString();
1678
1679 missLatency[access_idx]
1680 .init(system->maxMasters())
1681 .name(name() + "." + cstr + "_miss_latency")
1682 .desc("number of " + cstr + " miss cycles")
1683 .flags(total | nozero | nonan)
1684 ;
1685 for (int i = 0; i < system->maxMasters(); i++) {
1686 missLatency[access_idx].subname(i, system->getMasterName(i));
1687 }
1688 }
1689
1690 demandMissLatency
1691 .name(name() + ".demand_miss_latency")
1692 .desc("number of demand (read+write) miss cycles")
1693 .flags(total | nozero | nonan)
1694 ;
1695 demandMissLatency = SUM_DEMAND(missLatency);
1696 for (int i = 0; i < system->maxMasters(); i++) {
1697 demandMissLatency.subname(i, system->getMasterName(i));
1698 }
1699
1700 overallMissLatency
1701 .name(name() + ".overall_miss_latency")
1702 .desc("number of overall miss cycles")
1703 .flags(total | nozero | nonan)
1704 ;
1705 overallMissLatency = demandMissLatency + SUM_NON_DEMAND(missLatency);
1706 for (int i = 0; i < system->maxMasters(); i++) {
1707 overallMissLatency.subname(i, system->getMasterName(i));
1708 }
1709
1710 // access formulas
1711 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1712 MemCmd cmd(access_idx);
1713 const string &cstr = cmd.toString();
1714
1715 accesses[access_idx]
1716 .name(name() + "." + cstr + "_accesses")
1717 .desc("number of " + cstr + " accesses(hits+misses)")
1718 .flags(total | nozero | nonan)
1719 ;
1720 accesses[access_idx] = hits[access_idx] + misses[access_idx];
1721
1722 for (int i = 0; i < system->maxMasters(); i++) {
1723 accesses[access_idx].subname(i, system->getMasterName(i));
1724 }
1725 }
1726
1727 demandAccesses
1728 .name(name() + ".demand_accesses")
1729 .desc("number of demand (read+write) accesses")
1730 .flags(total | nozero | nonan)
1731 ;
1732 demandAccesses = demandHits + demandMisses;
1733 for (int i = 0; i < system->maxMasters(); i++) {
1734 demandAccesses.subname(i, system->getMasterName(i));
1735 }
1736
1737 overallAccesses
1738 .name(name() + ".overall_accesses")
1739 .desc("number of overall (read+write) accesses")
1740 .flags(total | nozero | nonan)
1741 ;
1742 overallAccesses = overallHits + overallMisses;
1743 for (int i = 0; i < system->maxMasters(); i++) {
1744 overallAccesses.subname(i, system->getMasterName(i));
1745 }
1746
1747 // miss rate formulas
1748 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1749 MemCmd cmd(access_idx);
1750 const string &cstr = cmd.toString();
1751
1752 missRate[access_idx]
1753 .name(name() + "." + cstr + "_miss_rate")
1754 .desc("miss rate for " + cstr + " accesses")
1755 .flags(total | nozero | nonan)
1756 ;
1757 missRate[access_idx] = misses[access_idx] / accesses[access_idx];
1758
1759 for (int i = 0; i < system->maxMasters(); i++) {
1760 missRate[access_idx].subname(i, system->getMasterName(i));
1761 }
1762 }
1763
1764 demandMissRate
1765 .name(name() + ".demand_miss_rate")
1766 .desc("miss rate for demand accesses")
1767 .flags(total | nozero | nonan)
1768 ;
1769 demandMissRate = demandMisses / demandAccesses;
1770 for (int i = 0; i < system->maxMasters(); i++) {
1771 demandMissRate.subname(i, system->getMasterName(i));
1772 }
1773
1774 overallMissRate
1775 .name(name() + ".overall_miss_rate")
1776 .desc("miss rate for overall accesses")
1777 .flags(total | nozero | nonan)
1778 ;
1779 overallMissRate = overallMisses / overallAccesses;
1780 for (int i = 0; i < system->maxMasters(); i++) {
1781 overallMissRate.subname(i, system->getMasterName(i));
1782 }
1783
1784 // miss latency formulas
1785 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1786 MemCmd cmd(access_idx);
1787 const string &cstr = cmd.toString();
1788
1789 avgMissLatency[access_idx]
1790 .name(name() + "." + cstr + "_avg_miss_latency")
1791 .desc("average " + cstr + " miss latency")
1792 .flags(total | nozero | nonan)
1793 ;
1794 avgMissLatency[access_idx] =
1795 missLatency[access_idx] / misses[access_idx];
1796
1797 for (int i = 0; i < system->maxMasters(); i++) {
1798 avgMissLatency[access_idx].subname(i, system->getMasterName(i));
1799 }
1800 }
1801
1802 demandAvgMissLatency
1803 .name(name() + ".demand_avg_miss_latency")
1804 .desc("average overall miss latency")
1805 .flags(total | nozero | nonan)
1806 ;
1807 demandAvgMissLatency = demandMissLatency / demandMisses;
1808 for (int i = 0; i < system->maxMasters(); i++) {
1809 demandAvgMissLatency.subname(i, system->getMasterName(i));
1810 }
1811
1812 overallAvgMissLatency
1813 .name(name() + ".overall_avg_miss_latency")
1814 .desc("average overall miss latency")
1815 .flags(total | nozero | nonan)
1816 ;
1817 overallAvgMissLatency = overallMissLatency / overallMisses;
1818 for (int i = 0; i < system->maxMasters(); i++) {
1819 overallAvgMissLatency.subname(i, system->getMasterName(i));
1820 }
1821
1822 blocked_cycles.init(NUM_BLOCKED_CAUSES);
1823 blocked_cycles
1824 .name(name() + ".blocked_cycles")
1825 .desc("number of cycles access was blocked")
1826 .subname(Blocked_NoMSHRs, "no_mshrs")
1827 .subname(Blocked_NoTargets, "no_targets")
1828 ;
1829
1830
1831 blocked_causes.init(NUM_BLOCKED_CAUSES);
1832 blocked_causes
1833 .name(name() + ".blocked")
1834 .desc("number of cycles access was blocked")
1835 .subname(Blocked_NoMSHRs, "no_mshrs")
1836 .subname(Blocked_NoTargets, "no_targets")
1837 ;
1838
1839 avg_blocked
1840 .name(name() + ".avg_blocked_cycles")
1841 .desc("average number of cycles each access was blocked")
1842 .subname(Blocked_NoMSHRs, "no_mshrs")
1843 .subname(Blocked_NoTargets, "no_targets")
1844 ;
1845
1846 avg_blocked = blocked_cycles / blocked_causes;
1847
1848 unusedPrefetches
1849 .name(name() + ".unused_prefetches")
1850 .desc("number of HardPF blocks evicted w/o reference")
1851 .flags(nozero)
1852 ;
1853
1854 writebacks
1855 .init(system->maxMasters())
1856 .name(name() + ".writebacks")
1857 .desc("number of writebacks")
1858 .flags(total | nozero | nonan)
1859 ;
1860 for (int i = 0; i < system->maxMasters(); i++) {
1861 writebacks.subname(i, system->getMasterName(i));
1862 }
1863
1864 // MSHR statistics
1865 // MSHR hit statistics
1866 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1867 MemCmd cmd(access_idx);
1868 const string &cstr = cmd.toString();
1869
1870 mshr_hits[access_idx]
1871 .init(system->maxMasters())
1872 .name(name() + "." + cstr + "_mshr_hits")
1873 .desc("number of " + cstr + " MSHR hits")
1874 .flags(total | nozero | nonan)
1875 ;
1876 for (int i = 0; i < system->maxMasters(); i++) {
1877 mshr_hits[access_idx].subname(i, system->getMasterName(i));
1878 }
1879 }
1880
1881 demandMshrHits
1882 .name(name() + ".demand_mshr_hits")
1883 .desc("number of demand (read+write) MSHR hits")
1884 .flags(total | nozero | nonan)
1885 ;
1886 demandMshrHits = SUM_DEMAND(mshr_hits);
1887 for (int i = 0; i < system->maxMasters(); i++) {
1888 demandMshrHits.subname(i, system->getMasterName(i));
1889 }
1890
1891 overallMshrHits
1892 .name(name() + ".overall_mshr_hits")
1893 .desc("number of overall MSHR hits")
1894 .flags(total | nozero | nonan)
1895 ;
1896 overallMshrHits = demandMshrHits + SUM_NON_DEMAND(mshr_hits);
1897 for (int i = 0; i < system->maxMasters(); i++) {
1898 overallMshrHits.subname(i, system->getMasterName(i));
1899 }
1900
1901 // MSHR miss statistics
1902 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1903 MemCmd cmd(access_idx);
1904 const string &cstr = cmd.toString();
1905
1906 mshr_misses[access_idx]
1907 .init(system->maxMasters())
1908 .name(name() + "." + cstr + "_mshr_misses")
1909 .desc("number of " + cstr + " MSHR misses")
1910 .flags(total | nozero | nonan)
1911 ;
1912 for (int i = 0; i < system->maxMasters(); i++) {
1913 mshr_misses[access_idx].subname(i, system->getMasterName(i));
1914 }
1915 }
1916
1917 demandMshrMisses
1918 .name(name() + ".demand_mshr_misses")
1919 .desc("number of demand (read+write) MSHR misses")
1920 .flags(total | nozero | nonan)
1921 ;
1922 demandMshrMisses = SUM_DEMAND(mshr_misses);
1923 for (int i = 0; i < system->maxMasters(); i++) {
1924 demandMshrMisses.subname(i, system->getMasterName(i));
1925 }
1926
1927 overallMshrMisses
1928 .name(name() + ".overall_mshr_misses")
1929 .desc("number of overall MSHR misses")
1930 .flags(total | nozero | nonan)
1931 ;
1932 overallMshrMisses = demandMshrMisses + SUM_NON_DEMAND(mshr_misses);
1933 for (int i = 0; i < system->maxMasters(); i++) {
1934 overallMshrMisses.subname(i, system->getMasterName(i));
1935 }
1936
1937 // MSHR miss latency statistics
1938 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1939 MemCmd cmd(access_idx);
1940 const string &cstr = cmd.toString();
1941
1942 mshr_miss_latency[access_idx]
1943 .init(system->maxMasters())
1944 .name(name() + "." + cstr + "_mshr_miss_latency")
1945 .desc("number of " + cstr + " MSHR miss cycles")
1946 .flags(total | nozero | nonan)
1947 ;
1948 for (int i = 0; i < system->maxMasters(); i++) {
1949 mshr_miss_latency[access_idx].subname(i, system->getMasterName(i));
1950 }
1951 }
1952
1953 demandMshrMissLatency
1954 .name(name() + ".demand_mshr_miss_latency")
1955 .desc("number of demand (read+write) MSHR miss cycles")
1956 .flags(total | nozero | nonan)
1957 ;
1958 demandMshrMissLatency = SUM_DEMAND(mshr_miss_latency);
1959 for (int i = 0; i < system->maxMasters(); i++) {
1960 demandMshrMissLatency.subname(i, system->getMasterName(i));
1961 }
1962
1963 overallMshrMissLatency
1964 .name(name() + ".overall_mshr_miss_latency")
1965 .desc("number of overall MSHR miss cycles")
1966 .flags(total | nozero | nonan)
1967 ;
1968 overallMshrMissLatency =
1969 demandMshrMissLatency + SUM_NON_DEMAND(mshr_miss_latency);
1970 for (int i = 0; i < system->maxMasters(); i++) {
1971 overallMshrMissLatency.subname(i, system->getMasterName(i));
1972 }
1973
1974 // MSHR uncacheable statistics
1975 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1976 MemCmd cmd(access_idx);
1977 const string &cstr = cmd.toString();
1978
1979 mshr_uncacheable[access_idx]
1980 .init(system->maxMasters())
1981 .name(name() + "." + cstr + "_mshr_uncacheable")
1982 .desc("number of " + cstr + " MSHR uncacheable")
1983 .flags(total | nozero | nonan)
1984 ;
1985 for (int i = 0; i < system->maxMasters(); i++) {
1986 mshr_uncacheable[access_idx].subname(i, system->getMasterName(i));
1987 }
1988 }
1989
1990 overallMshrUncacheable
1991 .name(name() + ".overall_mshr_uncacheable_misses")
1992 .desc("number of overall MSHR uncacheable misses")
1993 .flags(total | nozero | nonan)
1994 ;
1995 overallMshrUncacheable =
1996 SUM_DEMAND(mshr_uncacheable) + SUM_NON_DEMAND(mshr_uncacheable);
1997 for (int i = 0; i < system->maxMasters(); i++) {
1998 overallMshrUncacheable.subname(i, system->getMasterName(i));
1999 }
2000
2001 // MSHR miss latency statistics
2002 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2003 MemCmd cmd(access_idx);
2004 const string &cstr = cmd.toString();
2005
2006 mshr_uncacheable_lat[access_idx]
2007 .init(system->maxMasters())
2008 .name(name() + "." + cstr + "_mshr_uncacheable_latency")
2009 .desc("number of " + cstr + " MSHR uncacheable cycles")
2010 .flags(total | nozero | nonan)
2011 ;
2012 for (int i = 0; i < system->maxMasters(); i++) {
2013 mshr_uncacheable_lat[access_idx].subname(
2014 i, system->getMasterName(i));
2015 }
2016 }
2017
2018 overallMshrUncacheableLatency
2019 .name(name() + ".overall_mshr_uncacheable_latency")
2020 .desc("number of overall MSHR uncacheable cycles")
2021 .flags(total | nozero | nonan)
2022 ;
2023 overallMshrUncacheableLatency =
2024 SUM_DEMAND(mshr_uncacheable_lat) +
2025 SUM_NON_DEMAND(mshr_uncacheable_lat);
2026 for (int i = 0; i < system->maxMasters(); i++) {
2027 overallMshrUncacheableLatency.subname(i, system->getMasterName(i));
2028 }
2029
2030#if 0
2031 // MSHR access formulas
2032 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2033 MemCmd cmd(access_idx);
2034 const string &cstr = cmd.toString();
2035
2036 mshrAccesses[access_idx]
2037 .name(name() + "." + cstr + "_mshr_accesses")
2038 .desc("number of " + cstr + " mshr accesses(hits+misses)")
2039 .flags(total | nozero | nonan)
2040 ;
2041 mshrAccesses[access_idx] =
2042 mshr_hits[access_idx] + mshr_misses[access_idx]
2043 + mshr_uncacheable[access_idx];
2044 }
2045
2046 demandMshrAccesses
2047 .name(name() + ".demand_mshr_accesses")
2048 .desc("number of demand (read+write) mshr accesses")
2049 .flags(total | nozero | nonan)
2050 ;
2051 demandMshrAccesses = demandMshrHits + demandMshrMisses;
2052
2053 overallMshrAccesses
2054 .name(name() + ".overall_mshr_accesses")
2055 .desc("number of overall (read+write) mshr accesses")
2056 .flags(total | nozero | nonan)
2057 ;
2058 overallMshrAccesses = overallMshrHits + overallMshrMisses
2059 + overallMshrUncacheable;
2060#endif
2061
2062 // MSHR miss rate formulas
2063 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2064 MemCmd cmd(access_idx);
2065 const string &cstr = cmd.toString();
2066
2067 mshrMissRate[access_idx]
2068 .name(name() + "." + cstr + "_mshr_miss_rate")
2069 .desc("mshr miss rate for " + cstr + " accesses")
2070 .flags(total | nozero | nonan)
2071 ;
2072 mshrMissRate[access_idx] =
2073 mshr_misses[access_idx] / accesses[access_idx];
2074
2075 for (int i = 0; i < system->maxMasters(); i++) {
2076 mshrMissRate[access_idx].subname(i, system->getMasterName(i));
2077 }
2078 }
2079
2080 demandMshrMissRate
2081 .name(name() + ".demand_mshr_miss_rate")
2082 .desc("mshr miss rate for demand accesses")
2083 .flags(total | nozero | nonan)
2084 ;
2085 demandMshrMissRate = demandMshrMisses / demandAccesses;
2086 for (int i = 0; i < system->maxMasters(); i++) {
2087 demandMshrMissRate.subname(i, system->getMasterName(i));
2088 }
2089
2090 overallMshrMissRate
2091 .name(name() + ".overall_mshr_miss_rate")
2092 .desc("mshr miss rate for overall accesses")
2093 .flags(total | nozero | nonan)
2094 ;
2095 overallMshrMissRate = overallMshrMisses / overallAccesses;
2096 for (int i = 0; i < system->maxMasters(); i++) {
2097 overallMshrMissRate.subname(i, system->getMasterName(i));
2098 }
2099
2100 // mshrMiss latency formulas
2101 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2102 MemCmd cmd(access_idx);
2103 const string &cstr = cmd.toString();
2104
2105 avgMshrMissLatency[access_idx]
2106 .name(name() + "." + cstr + "_avg_mshr_miss_latency")
2107 .desc("average " + cstr + " mshr miss latency")
2108 .flags(total | nozero | nonan)
2109 ;
2110 avgMshrMissLatency[access_idx] =
2111 mshr_miss_latency[access_idx] / mshr_misses[access_idx];
2112
2113 for (int i = 0; i < system->maxMasters(); i++) {
2114 avgMshrMissLatency[access_idx].subname(
2115 i, system->getMasterName(i));
2116 }
2117 }
2118
2119 demandAvgMshrMissLatency
2120 .name(name() + ".demand_avg_mshr_miss_latency")
2121 .desc("average overall mshr miss latency")
2122 .flags(total | nozero | nonan)
2123 ;
2124 demandAvgMshrMissLatency = demandMshrMissLatency / demandMshrMisses;
2125 for (int i = 0; i < system->maxMasters(); i++) {
2126 demandAvgMshrMissLatency.subname(i, system->getMasterName(i));
2127 }
2128
2129 overallAvgMshrMissLatency
2130 .name(name() + ".overall_avg_mshr_miss_latency")
2131 .desc("average overall mshr miss latency")
2132 .flags(total | nozero | nonan)
2133 ;
2134 overallAvgMshrMissLatency = overallMshrMissLatency / overallMshrMisses;
2135 for (int i = 0; i < system->maxMasters(); i++) {
2136 overallAvgMshrMissLatency.subname(i, system->getMasterName(i));
2137 }
2138
2139 // mshrUncacheable latency formulas
2140 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2141 MemCmd cmd(access_idx);
2142 const string &cstr = cmd.toString();
2143
2144 avgMshrUncacheableLatency[access_idx]
2145 .name(name() + "." + cstr + "_avg_mshr_uncacheable_latency")
2146 .desc("average " + cstr + " mshr uncacheable latency")
2147 .flags(total | nozero | nonan)
2148 ;
2149 avgMshrUncacheableLatency[access_idx] =
2150 mshr_uncacheable_lat[access_idx] / mshr_uncacheable[access_idx];
2151
2152 for (int i = 0; i < system->maxMasters(); i++) {
2153 avgMshrUncacheableLatency[access_idx].subname(
2154 i, system->getMasterName(i));
2155 }
2156 }
2157
2158 overallAvgMshrUncacheableLatency
2159 .name(name() + ".overall_avg_mshr_uncacheable_latency")
2160 .desc("average overall mshr uncacheable latency")
2161 .flags(total | nozero | nonan)
2162 ;
2163 overallAvgMshrUncacheableLatency =
2164 overallMshrUncacheableLatency / overallMshrUncacheable;
2165 for (int i = 0; i < system->maxMasters(); i++) {
2166 overallAvgMshrUncacheableLatency.subname(i, system->getMasterName(i));
2167 }
2168
2169 replacements
2170 .name(name() + ".replacements")
2171 .desc("number of replacements")
2172 ;
2173}
2174
2175///////////////
2176//
2177// CpuSidePort
2178//
2179///////////////
2180bool
2181BaseCache::CpuSidePort::recvTimingSnoopResp(PacketPtr pkt)
2182{
2183 // Snoops shouldn't happen when bypassing caches
2184 assert(!cache->system->bypassCaches());
2185
2186 assert(pkt->isResponse());
2187
2188 // Express snoop responses from master to slave, e.g., from L1 to L2
2189 cache->recvTimingSnoopResp(pkt);
2190 return true;
2191}
2192
2193
2194bool
2195BaseCache::CpuSidePort::tryTiming(PacketPtr pkt)
2196{
2197 if (cache->system->bypassCaches() || pkt->isExpressSnoop()) {
2198 // always let express snoop packets through even if blocked
2199 return true;
2200 } else if (blocked || mustSendRetry) {
2201 // either already committed to send a retry, or blocked
2202 mustSendRetry = true;
2203 return false;
2204 }
2205 mustSendRetry = false;
2206 return true;
2207}
2208
2209bool
2210BaseCache::CpuSidePort::recvTimingReq(PacketPtr pkt)
2211{
2212 assert(pkt->isRequest());
2213
2214 if (cache->system->bypassCaches()) {
2215 // Just forward the packet if caches are disabled.
2216 // @todo This should really enqueue the packet rather
2217 bool M5_VAR_USED success = cache->memSidePort.sendTimingReq(pkt);
2218 assert(success);
2219 return true;
2220 } else if (tryTiming(pkt)) {
2221 cache->recvTimingReq(pkt);
2222 return true;
2223 }
2224 return false;
2225}
2226
2227Tick
2228BaseCache::CpuSidePort::recvAtomic(PacketPtr pkt)
2229{
2230 if (cache->system->bypassCaches()) {
2231 // Forward the request if the system is in cache bypass mode.
2232 return cache->memSidePort.sendAtomic(pkt);
2233 } else {
2234 return cache->recvAtomic(pkt);
2235 }
2236}
2237
2238void
2239BaseCache::CpuSidePort::recvFunctional(PacketPtr pkt)
2240{
2241 if (cache->system->bypassCaches()) {
2242 // The cache should be flushed if we are in cache bypass mode,
2243 // so we don't need to check if we need to update anything.
2244 cache->memSidePort.sendFunctional(pkt);
2245 return;
2246 }
2247
2248 // functional request
2249 cache->functionalAccess(pkt, true);
2250}
2251
2252AddrRangeList
2253BaseCache::CpuSidePort::getAddrRanges() const
2254{
2255 return cache->getAddrRanges();
2256}
2257
2258
2259BaseCache::
2260CpuSidePort::CpuSidePort(const std::string &_name, BaseCache *_cache,
2261 const std::string &_label)
2262 : CacheSlavePort(_name, _cache, _label), cache(_cache)
2263{
2264}
2265
2266///////////////
2267//
2268// MemSidePort
2269//
2270///////////////
2271bool
2272BaseCache::MemSidePort::recvTimingResp(PacketPtr pkt)
2273{
2274 cache->recvTimingResp(pkt);
2275 return true;
2276}
2277
2278// Express snooping requests to memside port
2279void
2280BaseCache::MemSidePort::recvTimingSnoopReq(PacketPtr pkt)
2281{
2282 // Snoops shouldn't happen when bypassing caches
2283 assert(!cache->system->bypassCaches());
2284
2285 // handle snooping requests
2286 cache->recvTimingSnoopReq(pkt);
2287}
2288
2289Tick
2290BaseCache::MemSidePort::recvAtomicSnoop(PacketPtr pkt)
2291{
2292 // Snoops shouldn't happen when bypassing caches
2293 assert(!cache->system->bypassCaches());
2294
2295 return cache->recvAtomicSnoop(pkt);
2296}
2297
2298void
2299BaseCache::MemSidePort::recvFunctionalSnoop(PacketPtr pkt)
2300{
2301 // Snoops shouldn't happen when bypassing caches
2302 assert(!cache->system->bypassCaches());
2303
2304 // functional snoop (note that in contrast to atomic we don't have
2305 // a specific functionalSnoop method, as they have the same
2306 // behaviour regardless)
2307 cache->functionalAccess(pkt, false);
2308}
2309
2310void
2311BaseCache::CacheReqPacketQueue::sendDeferredPacket()
2312{
2313 // sanity check
2314 assert(!waitingOnRetry);
2315
2316 // there should never be any deferred request packets in the
2317 // queue, instead we resly on the cache to provide the packets
2318 // from the MSHR queue or write queue
2319 assert(deferredPacketReadyTime() == MaxTick);
2320
2321 // check for request packets (requests & writebacks)
2322 QueueEntry* entry = cache.getNextQueueEntry();
2323
2324 if (!entry) {
2325 // can happen if e.g. we attempt a writeback and fail, but
2326 // before the retry, the writeback is eliminated because
2327 // we snoop another cache's ReadEx.
2328 } else {
2329 // let our snoop responses go first if there are responses to
2330 // the same addresses
2331 if (checkConflictingSnoop(entry->blkAddr)) {
2332 return;
2333 }
2334 waitingOnRetry = entry->sendPacket(cache);
2335 }
2336
2337 // if we succeeded and are not waiting for a retry, schedule the
2338 // next send considering when the next queue is ready, note that
2339 // snoop responses have their own packet queue and thus schedule
2340 // their own events
2341 if (!waitingOnRetry) {
2342 schedSendEvent(cache.nextQueueReadyTime());
2343 }
2344}
2345
2346BaseCache::MemSidePort::MemSidePort(const std::string &_name,
2347 BaseCache *_cache,
2348 const std::string &_label)
2349 : CacheMasterPort(_name, _cache, _reqQueue, _snoopRespQueue),
2350 _reqQueue(*_cache, *this, _snoopRespQueue, _label),
2351 _snoopRespQueue(*_cache, *this, _label), cache(_cache)
2352{
2353}
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