1/*
2 * Copyright (c) 2012-2013, 2018-2019 ARM Limited
3 * All rights reserved.
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2003-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Erik Hallnor
41 * Nikos Nikoleris
42 */
43
44/**
45 * @file
46 * Definition of BaseCache functions.
47 */
48
49#include "mem/cache/base.hh"
50
51#include "base/compiler.hh"
52#include "base/logging.hh"
53#include "debug/Cache.hh"
54#include "debug/CacheComp.hh"
55#include "debug/CachePort.hh"
56#include "debug/CacheRepl.hh"
57#include "debug/CacheVerbose.hh"
58#include "mem/cache/compressors/base.hh"
59#include "mem/cache/mshr.hh"
60#include "mem/cache/prefetch/base.hh"
61#include "mem/cache/queue_entry.hh"
62#include "mem/cache/tags/super_blk.hh"
63#include "params/BaseCache.hh"
64#include "params/WriteAllocator.hh"
65#include "sim/core.hh"
66
67class BaseMasterPort;
68class BaseSlavePort;
69
70using namespace std;
71
72BaseCache::CacheSlavePort::CacheSlavePort(const std::string &_name,
73 BaseCache *_cache,
74 const std::string &_label)
75 : QueuedSlavePort(_name, _cache, queue),
76 queue(*_cache, *this, true, _label),
77 blocked(false), mustSendRetry(false),
78 sendRetryEvent([this]{ processSendRetry(); }, _name)
79{
80}
81
82BaseCache::BaseCache(const BaseCacheParams *p, unsigned blk_size)
83 : ClockedObject(p),
84 cpuSidePort (p->name + ".cpu_side", this, "CpuSidePort"),
85 memSidePort(p->name + ".mem_side", this, "MemSidePort"),
86 mshrQueue("MSHRs", p->mshrs, 0, p->demand_mshr_reserve), // see below
87 writeBuffer("write buffer", p->write_buffers, p->mshrs), // see below
88 tags(p->tags),
89 compressor(p->compressor),
90 prefetcher(p->prefetcher),
91 writeAllocator(p->write_allocator),
92 writebackClean(p->writeback_clean),
93 tempBlockWriteback(nullptr),
94 writebackTempBlockAtomicEvent([this]{ writebackTempBlockAtomic(); },
95 name(), false,
96 EventBase::Delayed_Writeback_Pri),
97 blkSize(blk_size),
98 lookupLatency(p->tag_latency),
99 dataLatency(p->data_latency),
100 forwardLatency(p->tag_latency),
101 fillLatency(p->data_latency),
102 responseLatency(p->response_latency),
103 sequentialAccess(p->sequential_access),
104 numTarget(p->tgts_per_mshr),
105 forwardSnoops(true),
106 clusivity(p->clusivity),
107 isReadOnly(p->is_read_only),
108 blocked(0),
109 order(0),
110 noTargetMSHR(nullptr),
111 missCount(p->max_miss_count),
112 addrRanges(p->addr_ranges.begin(), p->addr_ranges.end()),
113 system(p->system)
114{
115 // the MSHR queue has no reserve entries as we check the MSHR
116 // queue on every single allocation, whereas the write queue has
117 // as many reserve entries as we have MSHRs, since every MSHR may
118 // eventually require a writeback, and we do not check the write
119 // buffer before committing to an MSHR
120
121 // forward snoops is overridden in init() once we can query
122 // whether the connected master is actually snooping or not
123
124 tempBlock = new TempCacheBlk(blkSize);
125
126 tags->tagsInit();
127 if (prefetcher)
128 prefetcher->setCache(this);
129}
130
131BaseCache::~BaseCache()
132{
133 delete tempBlock;
134}
135
136void
137BaseCache::CacheSlavePort::setBlocked()
138{
139 assert(!blocked);
140 DPRINTF(CachePort, "Port is blocking new requests\n");
141 blocked = true;
142 // if we already scheduled a retry in this cycle, but it has not yet
143 // happened, cancel it
144 if (sendRetryEvent.scheduled()) {
145 owner.deschedule(sendRetryEvent);
146 DPRINTF(CachePort, "Port descheduled retry\n");
147 mustSendRetry = true;
148 }
149}
150
151void
152BaseCache::CacheSlavePort::clearBlocked()
153{
154 assert(blocked);
155 DPRINTF(CachePort, "Port is accepting new requests\n");
156 blocked = false;
157 if (mustSendRetry) {
158 // @TODO: need to find a better time (next cycle?)
159 owner.schedule(sendRetryEvent, curTick() + 1);
160 }
161}
162
163void
164BaseCache::CacheSlavePort::processSendRetry()
165{
166 DPRINTF(CachePort, "Port is sending retry\n");
167
168 // reset the flag and call retry
169 mustSendRetry = false;
170 sendRetryReq();
171}
172
173Addr
174BaseCache::regenerateBlkAddr(CacheBlk* blk)
175{
176 if (blk != tempBlock) {
177 return tags->regenerateBlkAddr(blk);
178 } else {
179 return tempBlock->getAddr();
180 }
181}
182
183void
184BaseCache::init()
185{
186 if (!cpuSidePort.isConnected() || !memSidePort.isConnected())
187 fatal("Cache ports on %s are not connected\n", name());
188 cpuSidePort.sendRangeChange();
189 forwardSnoops = cpuSidePort.isSnooping();
190}
191
192Port &
193BaseCache::getPort(const std::string &if_name, PortID idx)
194{
195 if (if_name == "mem_side") {
196 return memSidePort;
197 } else if (if_name == "cpu_side") {
198 return cpuSidePort;
199 } else {
200 return ClockedObject::getPort(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 // These delays should have been consumed by now
220 assert(pkt->headerDelay == 0);
221 assert(pkt->payloadDelay == 0);
222
223 pkt->makeTimingResponse();
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 the value of lat overriden by access(), which calls
229 // the calculateAccessLatency() function.
230 cpuSidePort.schedTimingResp(pkt, request_time);
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 (writeAllocator &&
248 pkt && pkt->isWrite() && !pkt->req->isUncacheable()) {
249 writeAllocator->updateMode(pkt->getAddr(), pkt->getSize(),
250 pkt->getBlockAddr(blkSize));
251 }
252
253 if (mshr) {
254 /// MSHR hit
255 /// @note writebacks will be checked in getNextMSHR()
256 /// for any conflicting requests to the same block
257
258 //@todo remove hw_pf here
259
260 // Coalesce unless it was a software prefetch (see above).
261 if (pkt) {
262 assert(!pkt->isWriteback());
263 // CleanEvicts corresponding to blocks which have
264 // outstanding requests in MSHRs are simply sunk here
265 if (pkt->cmd == MemCmd::CleanEvict) {
266 pendingDelete.reset(pkt);
267 } else if (pkt->cmd == MemCmd::WriteClean) {
268 // A WriteClean should never coalesce with any
269 // outstanding cache maintenance requests.
270
271 // We use forward_time here because there is an
272 // uncached memory write, forwarded to WriteBuffer.
273 allocateWriteBuffer(pkt, forward_time);
274 } else {
275 DPRINTF(Cache, "%s coalescing MSHR for %s\n", __func__,
276 pkt->print());
277
278 assert(pkt->req->masterId() < system->maxMasters());
279 mshr_hits[pkt->cmdToIndex()][pkt->req->masterId()]++;
280
281 // We use forward_time here because it is the same
282 // considering new targets. We have multiple
283 // requests for the same address here. It
284 // specifies the latency to allocate an internal
285 // buffer and to schedule an event to the queued
286 // port and also takes into account the additional
287 // delay of the xbar.
288 mshr->allocateTarget(pkt, forward_time, order++,
289 allocOnFill(pkt->cmd));
290 if (mshr->getNumTargets() == numTarget) {
291 noTargetMSHR = mshr;
292 setBlocked(Blocked_NoTargets);
293 // need to be careful with this... if this mshr isn't
294 // ready yet (i.e. time > curTick()), we don't want to
295 // move it ahead of mshrs that are ready
296 // mshrQueue.moveToFront(mshr);
297 }
298 }
299 }
300 } else {
301 // no MSHR
302 assert(pkt->req->masterId() < system->maxMasters());
303 mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
304
305 if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean) {
306 // We use forward_time here because there is an
307 // writeback or writeclean, forwarded to WriteBuffer.
308 allocateWriteBuffer(pkt, forward_time);
309 } else {
310 if (blk && blk->isValid()) {
311 // If we have a write miss to a valid block, we
312 // need to mark the block non-readable. Otherwise
313 // if we allow reads while there's an outstanding
314 // write miss, the read could return stale data
315 // out of the cache block... a more aggressive
316 // system could detect the overlap (if any) and
317 // forward data out of the MSHRs, but we don't do
318 // that yet. Note that we do need to leave the
319 // block valid so that it stays in the cache, in
320 // case we get an upgrade response (and hence no
321 // new data) when the write miss completes.
322 // As long as CPUs do proper store/load forwarding
323 // internally, and have a sufficiently weak memory
324 // model, this is probably unnecessary, but at some
325 // point it must have seemed like we needed it...
326 assert((pkt->needsWritable() && !blk->isWritable()) ||
327 pkt->req->isCacheMaintenance());
328 blk->status &= ~BlkReadable;
329 }
330 // Here we are using forward_time, modelling the latency of
331 // a miss (outbound) just as forwardLatency, neglecting the
332 // lookupLatency component.
333 allocateMissBuffer(pkt, forward_time);
334 }
335 }
336}
337
338void
339BaseCache::recvTimingReq(PacketPtr pkt)
340{
341 // anything that is merely forwarded pays for the forward latency and
342 // the delay provided by the crossbar
343 Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
344
345 Cycles lat;
346 CacheBlk *blk = nullptr;
347 bool satisfied = false;
348 {
349 PacketList writebacks;
350 // Note that lat is passed by reference here. The function
351 // access() will set the lat value.
352 satisfied = access(pkt, blk, lat, writebacks);
353
354 // After the evicted blocks are selected, they must be forwarded
355 // to the write buffer to ensure they logically precede anything
356 // happening below
357 doWritebacks(writebacks, clockEdge(lat + forwardLatency));
358 }
359
360 // Here we charge the headerDelay that takes into account the latencies
361 // of the bus, if the packet comes from it.
362 // The latency charged is just the value set by the access() function.
363 // In case of a hit we are neglecting response latency.
364 // In case of a miss we are neglecting forward latency.
365 Tick request_time = clockEdge(lat);
366 // Here we reset the timing of the packet.
367 pkt->headerDelay = pkt->payloadDelay = 0;
368
369 if (satisfied) {
370 // notify before anything else as later handleTimingReqHit might turn
371 // the packet in a response
372 ppHit->notify(pkt);
373
374 if (prefetcher && blk && blk->wasPrefetched()) {
375 blk->status &= ~BlkHWPrefetched;
376 }
377
378 handleTimingReqHit(pkt, blk, request_time);
379 } else {
380 handleTimingReqMiss(pkt, blk, forward_time, request_time);
381
382 ppMiss->notify(pkt);
383 }
384
385 if (prefetcher) {
386 // track time of availability of next prefetch, if any
387 Tick next_pf_time = prefetcher->nextPrefetchReadyTime();
388 if (next_pf_time != MaxTick) {
389 schedMemSideSendEvent(next_pf_time);
390 }
391 }
392}
393
394void
395BaseCache::handleUncacheableWriteResp(PacketPtr pkt)
396{
397 Tick completion_time = clockEdge(responseLatency) +
398 pkt->headerDelay + pkt->payloadDelay;
399
400 // Reset the bus additional time as it is now accounted for
401 pkt->headerDelay = pkt->payloadDelay = 0;
402
403 cpuSidePort.schedTimingResp(pkt, completion_time);
404}
405
406void
407BaseCache::recvTimingResp(PacketPtr pkt)
408{
409 assert(pkt->isResponse());
410
411 // all header delay should be paid for by the crossbar, unless
412 // this is a prefetch response from above
413 panic_if(pkt->headerDelay != 0 && pkt->cmd != MemCmd::HardPFResp,
414 "%s saw a non-zero packet delay\n", name());
415
416 const bool is_error = pkt->isError();
417
418 if (is_error) {
419 DPRINTF(Cache, "%s: Cache received %s with error\n", __func__,
420 pkt->print());
421 }
422
423 DPRINTF(Cache, "%s: Handling response %s\n", __func__,
424 pkt->print());
425
426 // if this is a write, we should be looking at an uncacheable
427 // write
428 if (pkt->isWrite()) {
429 assert(pkt->req->isUncacheable());
430 handleUncacheableWriteResp(pkt);
431 return;
432 }
433
434 // we have dealt with any (uncacheable) writes above, from here on
435 // we know we are dealing with an MSHR due to a miss or a prefetch
436 MSHR *mshr = dynamic_cast<MSHR*>(pkt->popSenderState());
437 assert(mshr);
438
439 if (mshr == noTargetMSHR) {
440 // we always clear at least one target
441 clearBlocked(Blocked_NoTargets);
442 noTargetMSHR = nullptr;
443 }
444
445 // Initial target is used just for stats
446 QueueEntry::Target *initial_tgt = mshr->getTarget();
447 int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
448 Tick miss_latency = curTick() - initial_tgt->recvTime;
449
450 if (pkt->req->isUncacheable()) {
451 assert(pkt->req->masterId() < system->maxMasters());
452 mshr_uncacheable_lat[stats_cmd_idx][pkt->req->masterId()] +=
453 miss_latency;
454 } else {
455 assert(pkt->req->masterId() < system->maxMasters());
456 mshr_miss_latency[stats_cmd_idx][pkt->req->masterId()] +=
457 miss_latency;
458 }
459
460 PacketList writebacks;
461
462 bool is_fill = !mshr->isForward &&
463 (pkt->isRead() || pkt->cmd == MemCmd::UpgradeResp ||
464 mshr->wasWholeLineWrite);
465
466 // make sure that if the mshr was due to a whole line write then
467 // the response is an invalidation
468 assert(!mshr->wasWholeLineWrite || pkt->isInvalidate());
469
470 CacheBlk *blk = tags->findBlock(pkt->getAddr(), pkt->isSecure());
471
472 if (is_fill && !is_error) {
473 DPRINTF(Cache, "Block for addr %#llx being updated in Cache\n",
474 pkt->getAddr());
475
476 const bool allocate = (writeAllocator && mshr->wasWholeLineWrite) ?
477 writeAllocator->allocate() : mshr->allocOnFill();
478 blk = handleFill(pkt, blk, writebacks, allocate);
479 assert(blk != nullptr);
480 ppFill->notify(pkt);
481 }
482
483 if (blk && blk->isValid() && pkt->isClean() && !pkt->isInvalidate()) {
484 // The block was marked not readable while there was a pending
485 // cache maintenance operation, restore its flag.
486 blk->status |= BlkReadable;
487
488 // This was a cache clean operation (without invalidate)
489 // and we have a copy of the block already. Since there
490 // is no invalidation, we can promote targets that don't
491 // require a writable copy
492 mshr->promoteReadable();
493 }
494
495 if (blk && blk->isWritable() && !pkt->req->isCacheInvalidate()) {
496 // If at this point the referenced block is writable and the
497 // response is not a cache invalidate, we promote targets that
498 // were deferred as we couldn't guarrantee a writable copy
499 mshr->promoteWritable();
500 }
501
502 serviceMSHRTargets(mshr, pkt, blk);
503
504 if (mshr->promoteDeferredTargets()) {
505 // avoid later read getting stale data while write miss is
506 // outstanding.. see comment in timingAccess()
507 if (blk) {
508 blk->status &= ~BlkReadable;
509 }
510 mshrQueue.markPending(mshr);
511 schedMemSideSendEvent(clockEdge() + pkt->payloadDelay);
512 } else {
513 // while we deallocate an mshr from the queue we still have to
514 // check the isFull condition before and after as we might
515 // have been using the reserved entries already
516 const bool was_full = mshrQueue.isFull();
517 mshrQueue.deallocate(mshr);
518 if (was_full && !mshrQueue.isFull()) {
519 clearBlocked(Blocked_NoMSHRs);
520 }
521
522 // Request the bus for a prefetch if this deallocation freed enough
523 // MSHRs for a prefetch to take place
524 if (prefetcher && mshrQueue.canPrefetch()) {
525 Tick next_pf_time = std::max(prefetcher->nextPrefetchReadyTime(),
526 clockEdge());
527 if (next_pf_time != MaxTick)
528 schedMemSideSendEvent(next_pf_time);
529 }
530 }
531
532 // if we used temp block, check to see if its valid and then clear it out
533 if (blk == tempBlock && tempBlock->isValid()) {
534 evictBlock(blk, writebacks);
535 }
536
537 const Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
538 // copy writebacks to write buffer
539 doWritebacks(writebacks, forward_time);
540
541 DPRINTF(CacheVerbose, "%s: Leaving with %s\n", __func__, pkt->print());
542 delete pkt;
543}
544
545
546Tick
547BaseCache::recvAtomic(PacketPtr pkt)
548{
549 // should assert here that there are no outstanding MSHRs or
550 // writebacks... that would mean that someone used an atomic
551 // access in timing mode
552
553 // We use lookupLatency here because it is used to specify the latency
554 // to access.
555 Cycles lat = lookupLatency;
556
557 CacheBlk *blk = nullptr;
558 PacketList writebacks;
559 bool satisfied = access(pkt, blk, lat, writebacks);
560
561 if (pkt->isClean() && blk && blk->isDirty()) {
562 // A cache clean opearation is looking for a dirty
563 // block. If a dirty block is encountered a WriteClean
564 // will update any copies to the path to the memory
565 // until the point of reference.
566 DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
567 __func__, pkt->print(), blk->print());
568 PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(), pkt->id);
569 writebacks.push_back(wb_pkt);
570 pkt->setSatisfied();
571 }
572
573 // handle writebacks resulting from the access here to ensure they
574 // logically precede anything happening below
575 doWritebacksAtomic(writebacks);
576 assert(writebacks.empty());
577
578 if (!satisfied) {
579 lat += handleAtomicReqMiss(pkt, blk, writebacks);
580 }
581
582 // Note that we don't invoke the prefetcher at all in atomic mode.
583 // It's not clear how to do it properly, particularly for
584 // prefetchers that aggressively generate prefetch candidates and
585 // rely on bandwidth contention to throttle them; these will tend
586 // to pollute the cache in atomic mode since there is no bandwidth
587 // contention. If we ever do want to enable prefetching in atomic
588 // mode, though, this is the place to do it... see timingAccess()
589 // for an example (though we'd want to issue the prefetch(es)
590 // immediately rather than calling requestMemSideBus() as we do
591 // there).
592
593 // do any writebacks resulting from the response handling
594 doWritebacksAtomic(writebacks);
595
596 // if we used temp block, check to see if its valid and if so
597 // clear it out, but only do so after the call to recvAtomic is
598 // finished so that any downstream observers (such as a snoop
599 // filter), first see the fill, and only then see the eviction
600 if (blk == tempBlock && tempBlock->isValid()) {
601 // the atomic CPU calls recvAtomic for fetch and load/store
602 // sequentuially, and we may already have a tempBlock
603 // writeback from the fetch that we have not yet sent
604 if (tempBlockWriteback) {
605 // if that is the case, write the prevoius one back, and
606 // do not schedule any new event
607 writebackTempBlockAtomic();
608 } else {
609 // the writeback/clean eviction happens after the call to
610 // recvAtomic has finished (but before any successive
611 // calls), so that the response handling from the fill is
612 // allowed to happen first
613 schedule(writebackTempBlockAtomicEvent, curTick());
614 }
615
616 tempBlockWriteback = evictBlock(blk);
617 }
618
619 if (pkt->needsResponse()) {
620 pkt->makeAtomicResponse();
621 }
622
623 return lat * clockPeriod();
624}
625
626void
627BaseCache::functionalAccess(PacketPtr pkt, bool from_cpu_side)
628{
629 Addr blk_addr = pkt->getBlockAddr(blkSize);
630 bool is_secure = pkt->isSecure();
631 CacheBlk *blk = tags->findBlock(pkt->getAddr(), is_secure);
632 MSHR *mshr = mshrQueue.findMatch(blk_addr, is_secure);
633
634 pkt->pushLabel(name());
635
636 CacheBlkPrintWrapper cbpw(blk);
637
638 // Note that just because an L2/L3 has valid data doesn't mean an
639 // L1 doesn't have a more up-to-date modified copy that still
640 // needs to be found. As a result we always update the request if
641 // we have it, but only declare it satisfied if we are the owner.
642
643 // see if we have data at all (owned or otherwise)
644 bool have_data = blk && blk->isValid()
645 && pkt->trySatisfyFunctional(&cbpw, blk_addr, is_secure, blkSize,
646 blk->data);
647
648 // data we have is dirty if marked as such or if we have an
649 // in-service MSHR that is pending a modified line
650 bool have_dirty =
651 have_data && (blk->isDirty() ||
652 (mshr && mshr->inService && mshr->isPendingModified()));
653
654 bool done = have_dirty ||
655 cpuSidePort.trySatisfyFunctional(pkt) ||
656 mshrQueue.trySatisfyFunctional(pkt) ||
657 writeBuffer.trySatisfyFunctional(pkt) ||
658 memSidePort.trySatisfyFunctional(pkt);
659
660 DPRINTF(CacheVerbose, "%s: %s %s%s%s\n", __func__, pkt->print(),
661 (blk && blk->isValid()) ? "valid " : "",
662 have_data ? "data " : "", done ? "done " : "");
663
664 // We're leaving the cache, so pop cache->name() label
665 pkt->popLabel();
666
667 if (done) {
668 pkt->makeResponse();
669 } else {
670 // if it came as a request from the CPU side then make sure it
671 // continues towards the memory side
672 if (from_cpu_side) {
673 memSidePort.sendFunctional(pkt);
674 } else if (cpuSidePort.isSnooping()) {
675 // if it came from the memory side, it must be a snoop request
676 // and we should only forward it if we are forwarding snoops
677 cpuSidePort.sendFunctionalSnoop(pkt);
678 }
679 }
680}
681
682
683void
684BaseCache::cmpAndSwap(CacheBlk *blk, PacketPtr pkt)
685{
686 assert(pkt->isRequest());
687
688 uint64_t overwrite_val;
689 bool overwrite_mem;
690 uint64_t condition_val64;
691 uint32_t condition_val32;
692
693 int offset = pkt->getOffset(blkSize);
694 uint8_t *blk_data = blk->data + offset;
695
696 assert(sizeof(uint64_t) >= pkt->getSize());
697
698 overwrite_mem = true;
699 // keep a copy of our possible write value, and copy what is at the
700 // memory address into the packet
701 pkt->writeData((uint8_t *)&overwrite_val);
702 pkt->setData(blk_data);
703
704 if (pkt->req->isCondSwap()) {
705 if (pkt->getSize() == sizeof(uint64_t)) {
706 condition_val64 = pkt->req->getExtraData();
707 overwrite_mem = !std::memcmp(&condition_val64, blk_data,
708 sizeof(uint64_t));
709 } else if (pkt->getSize() == sizeof(uint32_t)) {
710 condition_val32 = (uint32_t)pkt->req->getExtraData();
711 overwrite_mem = !std::memcmp(&condition_val32, blk_data,
712 sizeof(uint32_t));
713 } else
714 panic("Invalid size for conditional read/write\n");
715 }
716
717 if (overwrite_mem) {
718 std::memcpy(blk_data, &overwrite_val, pkt->getSize());
719 blk->status |= BlkDirty;
720 }
721}
722
723QueueEntry*
724BaseCache::getNextQueueEntry()
725{
726 // Check both MSHR queue and write buffer for potential requests,
727 // note that null does not mean there is no request, it could
728 // simply be that it is not ready
729 MSHR *miss_mshr = mshrQueue.getNext();
730 WriteQueueEntry *wq_entry = writeBuffer.getNext();
731
732 // If we got a write buffer request ready, first priority is a
733 // full write buffer, otherwise we favour the miss requests
734 if (wq_entry && (writeBuffer.isFull() || !miss_mshr)) {
735 // need to search MSHR queue for conflicting earlier miss.
736 MSHR *conflict_mshr = mshrQueue.findPending(wq_entry);
737
738 if (conflict_mshr && conflict_mshr->order < wq_entry->order) {
739 // Service misses in order until conflict is cleared.
740 return conflict_mshr;
741
742 // @todo Note that we ignore the ready time of the conflict here
743 }
744
745 // No conflicts; issue write
746 return wq_entry;
747 } else if (miss_mshr) {
748 // need to check for conflicting earlier writeback
749 WriteQueueEntry *conflict_mshr = writeBuffer.findPending(miss_mshr);
750 if (conflict_mshr) {
751 // not sure why we don't check order here... it was in the
752 // original code but commented out.
753
754 // The only way this happens is if we are
755 // doing a write and we didn't have permissions
756 // then subsequently saw a writeback (owned got evicted)
757 // We need to make sure to perform the writeback first
758 // To preserve the dirty data, then we can issue the write
759
760 // should we return wq_entry here instead? I.e. do we
761 // have to flush writes in order? I don't think so... not
762 // for Alpha anyway. Maybe for x86?
763 return conflict_mshr;
764
765 // @todo Note that we ignore the ready time of the conflict here
766 }
767
768 // No conflicts; issue read
769 return miss_mshr;
770 }
771
772 // fall through... no pending requests. Try a prefetch.
773 assert(!miss_mshr && !wq_entry);
774 if (prefetcher && mshrQueue.canPrefetch()) {
775 // If we have a miss queue slot, we can try a prefetch
776 PacketPtr pkt = prefetcher->getPacket();
777 if (pkt) {
778 Addr pf_addr = pkt->getBlockAddr(blkSize);
779 if (!tags->findBlock(pf_addr, pkt->isSecure()) &&
780 !mshrQueue.findMatch(pf_addr, pkt->isSecure()) &&
781 !writeBuffer.findMatch(pf_addr, pkt->isSecure())) {
782 // Update statistic on number of prefetches issued
783 // (hwpf_mshr_misses)
784 assert(pkt->req->masterId() < system->maxMasters());
785 mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
786
787 // allocate an MSHR and return it, note
788 // that we send the packet straight away, so do not
789 // schedule the send
790 return allocateMissBuffer(pkt, curTick(), false);
791 } else {
792 // free the request and packet
793 delete pkt;
794 }
795 }
796 }
797
798 return nullptr;
799}
800
801bool
802BaseCache::updateCompressionData(CacheBlk *blk, const uint64_t* data,
803 PacketList &writebacks)
804{
805 // tempBlock does not exist in the tags, so don't do anything for it.
806 if (blk == tempBlock) {
807 return true;
808 }
809
810 // Get superblock of the given block
811 CompressionBlk* compression_blk = static_cast<CompressionBlk*>(blk);
812 const SuperBlk* superblock = static_cast<const SuperBlk*>(
813 compression_blk->getSectorBlock());
814
815 // The compressor is called to compress the updated data, so that its
816 // metadata can be updated.
817 std::size_t compression_size = 0;
818 Cycles compression_lat = Cycles(0);
819 Cycles decompression_lat = Cycles(0);
820 compressor->compress(data, compression_lat, decompression_lat,
821 compression_size);
822
823 // If block's compression factor increased, it may not be co-allocatable
824 // anymore. If so, some blocks might need to be evicted to make room for
825 // the bigger block
826
827 // Get previous compressed size
828 const std::size_t M5_VAR_USED prev_size = compression_blk->getSizeBits();
829
830 // Check if new data is co-allocatable
831 const bool is_co_allocatable = superblock->isCompressed(compression_blk) &&
832 superblock->canCoAllocate(compression_size);
833
834 // If block was compressed, possibly co-allocated with other blocks, and
835 // cannot be co-allocated anymore, one or more blocks must be evicted to
836 // make room for the expanded block. As of now we decide to evict the co-
837 // allocated blocks to make room for the expansion, but other approaches
838 // that take the replacement data of the superblock into account may
839 // generate better results
840 std::vector<CacheBlk*> evict_blks;
841 const bool was_compressed = compression_blk->isCompressed();
842 if (was_compressed && !is_co_allocatable) {
843 // Get all co-allocated blocks
844 for (const auto& sub_blk : superblock->blks) {
845 if (sub_blk->isValid() && (compression_blk != sub_blk)) {
846 // Check for transient state allocations. If any of the
847 // entries listed for eviction has a transient state, the
848 // allocation fails
849 const Addr repl_addr = regenerateBlkAddr(sub_blk);
850 const MSHR *repl_mshr =
851 mshrQueue.findMatch(repl_addr, sub_blk->isSecure());
852 if (repl_mshr) {
853 DPRINTF(CacheRepl, "Aborting data expansion of %s due " \
854 "to replacement of block in transient state: %s\n",
855 compression_blk->print(), sub_blk->print());
856 // Too hard to replace block with transient state, so it
857 // cannot be evicted. Mark the update as failed and expect
858 // the caller to evict this block. Since this is called
859 // only when writebacks arrive, and packets do not contain
860 // compressed data, there is no need to decompress
861 compression_blk->setSizeBits(blkSize * 8);
862 compression_blk->setDecompressionLatency(Cycles(0));
863 compression_blk->setUncompressed();
864 return false;
865 }
866
867 evict_blks.push_back(sub_blk);
868 }
869 }
870
871 // Update the number of data expansions
872 dataExpansions++;
873
874 DPRINTF(CacheComp, "Data expansion: expanding [%s] from %d to %d bits"
875 "\n", blk->print(), prev_size, compression_size);
876 }
877
878 // We always store compressed blocks when possible
879 if (is_co_allocatable) {
880 compression_blk->setCompressed();
881 } else {
882 compression_blk->setUncompressed();
883 }
884 compression_blk->setSizeBits(compression_size);
885 compression_blk->setDecompressionLatency(decompression_lat);
886
887 // Evict valid blocks
888 for (const auto& evict_blk : evict_blks) {
889 if (evict_blk->isValid()) {
890 if (evict_blk->wasPrefetched()) {
891 unusedPrefetches++;
892 }
893 evictBlock(evict_blk, writebacks);
894 }
895 }
896
897 return true;
898}
899
900void
901BaseCache::satisfyRequest(PacketPtr pkt, CacheBlk *blk, bool, bool)
902{
903 assert(pkt->isRequest());
904
905 assert(blk && blk->isValid());
906 // Occasionally this is not true... if we are a lower-level cache
907 // satisfying a string of Read and ReadEx requests from
908 // upper-level caches, a Read will mark the block as shared but we
909 // can satisfy a following ReadEx anyway since we can rely on the
910 // Read requester(s) to have buffered the ReadEx snoop and to
911 // invalidate their blocks after receiving them.
912 // assert(!pkt->needsWritable() || blk->isWritable());
913 assert(pkt->getOffset(blkSize) + pkt->getSize() <= blkSize);
914
915 // Check RMW operations first since both isRead() and
916 // isWrite() will be true for them
917 if (pkt->cmd == MemCmd::SwapReq) {
918 if (pkt->isAtomicOp()) {
919 // extract data from cache and save it into the data field in
920 // the packet as a return value from this atomic op
921 int offset = tags->extractBlkOffset(pkt->getAddr());
922 uint8_t *blk_data = blk->data + offset;
923 pkt->setData(blk_data);
924
925 // execute AMO operation
926 (*(pkt->getAtomicOp()))(blk_data);
927
928 // set block status to dirty
929 blk->status |= BlkDirty;
930 } else {
931 cmpAndSwap(blk, pkt);
932 }
933 } else if (pkt->isWrite()) {
934 // we have the block in a writable state and can go ahead,
935 // note that the line may be also be considered writable in
936 // downstream caches along the path to memory, but always
937 // Exclusive, and never Modified
938 assert(blk->isWritable());
939 // Write or WriteLine at the first cache with block in writable state
940 if (blk->checkWrite(pkt)) {
941 pkt->writeDataToBlock(blk->data, blkSize);
942 }
943 // Always mark the line as dirty (and thus transition to the
944 // Modified state) even if we are a failed StoreCond so we
945 // supply data to any snoops that have appended themselves to
946 // this cache before knowing the store will fail.
947 blk->status |= BlkDirty;
948 DPRINTF(CacheVerbose, "%s for %s (write)\n", __func__, pkt->print());
949 } else if (pkt->isRead()) {
950 if (pkt->isLLSC()) {
951 blk->trackLoadLocked(pkt);
952 }
953
954 // all read responses have a data payload
955 assert(pkt->hasRespData());
956 pkt->setDataFromBlock(blk->data, blkSize);
957 } else if (pkt->isUpgrade()) {
958 // sanity check
959 assert(!pkt->hasSharers());
960
961 if (blk->isDirty()) {
962 // we were in the Owned state, and a cache above us that
963 // has the line in Shared state needs to be made aware
964 // that the data it already has is in fact dirty
965 pkt->setCacheResponding();
966 blk->status &= ~BlkDirty;
967 }
968 } else if (pkt->isClean()) {
969 blk->status &= ~BlkDirty;
970 } else {
971 assert(pkt->isInvalidate());
972 invalidateBlock(blk);
973 DPRINTF(CacheVerbose, "%s for %s (invalidation)\n", __func__,
974 pkt->print());
975 }
976}
977
978/////////////////////////////////////////////////////
979//
980// Access path: requests coming in from the CPU side
981//
982/////////////////////////////////////////////////////
983Cycles
984BaseCache::calculateTagOnlyLatency(const uint32_t delay,
985 const Cycles lookup_lat) const
986{
987 // A tag-only access has to wait for the packet to arrive in order to
988 // perform the tag lookup.
989 return ticksToCycles(delay) + lookup_lat;
990}
991
992Cycles
993BaseCache::calculateAccessLatency(const CacheBlk* blk, const uint32_t delay,
994 const Cycles lookup_lat) const
995{
996 Cycles lat(0);
997
998 if (blk != nullptr) {
999 // As soon as the access arrives, for sequential accesses first access
1000 // tags, then the data entry. In the case of parallel accesses the
1001 // latency is dictated by the slowest of tag and data latencies.
1002 if (sequentialAccess) {
1003 lat = ticksToCycles(delay) + lookup_lat + dataLatency;
1004 } else {
1005 lat = ticksToCycles(delay) + std::max(lookup_lat, dataLatency);
1006 }
1007
1008 // Check if the block to be accessed is available. If not, apply the
1009 // access latency on top of when the block is ready to be accessed.
1010 const Tick tick = curTick() + delay;
1011 const Tick when_ready = blk->getWhenReady();
1012 if (when_ready > tick &&
1013 ticksToCycles(when_ready - tick) > lat) {
1014 lat += ticksToCycles(when_ready - tick);
1015 }
1016 } else {
1017 // In case of a miss, we neglect the data access in a parallel
1018 // configuration (i.e., the data access will be stopped as soon as
1019 // we find out it is a miss), and use the tag-only latency.
1020 lat = calculateTagOnlyLatency(delay, lookup_lat);
1021 }
1022
1023 return lat;
1024}
1025
1026bool
1027BaseCache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
1028 PacketList &writebacks)
1029{
1030 // sanity check
1031 assert(pkt->isRequest());
1032
1033 chatty_assert(!(isReadOnly && pkt->isWrite()),
1034 "Should never see a write in a read-only cache %s\n",
1035 name());
1036
1037 // Access block in the tags
1038 Cycles tag_latency(0);
1039 blk = tags->accessBlock(pkt->getAddr(), pkt->isSecure(), tag_latency);
1040
1041 DPRINTF(Cache, "%s for %s %s\n", __func__, pkt->print(),
1042 blk ? "hit " + blk->print() : "miss");
1043
1044 if (pkt->req->isCacheMaintenance()) {
1045 // A cache maintenance operation is always forwarded to the
1046 // memory below even if the block is found in dirty state.
1047
1048 // We defer any changes to the state of the block until we
1049 // create and mark as in service the mshr for the downstream
1050 // packet.
1051
1052 // Calculate access latency on top of when the packet arrives. This
1053 // takes into account the bus delay.
1054 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1055
1056 return false;
1057 }
1058
1059 if (pkt->isEviction()) {
1060 // We check for presence of block in above caches before issuing
1061 // Writeback or CleanEvict to write buffer. Therefore the only
1062 // possible cases can be of a CleanEvict packet coming from above
1063 // encountering a Writeback generated in this cache peer cache and
1064 // waiting in the write buffer. Cases of upper level peer caches
1065 // generating CleanEvict and Writeback or simply CleanEvict and
1066 // CleanEvict almost simultaneously will be caught by snoops sent out
1067 // by crossbar.
1068 WriteQueueEntry *wb_entry = writeBuffer.findMatch(pkt->getAddr(),
1069 pkt->isSecure());
1070 if (wb_entry) {
1071 assert(wb_entry->getNumTargets() == 1);
1072 PacketPtr wbPkt = wb_entry->getTarget()->pkt;
1073 assert(wbPkt->isWriteback());
1074
1075 if (pkt->isCleanEviction()) {
1076 // The CleanEvict and WritebackClean snoops into other
1077 // peer caches of the same level while traversing the
1078 // crossbar. If a copy of the block is found, the
1079 // packet is deleted in the crossbar. Hence, none of
1080 // the other upper level caches connected to this
1081 // cache have the block, so we can clear the
1082 // BLOCK_CACHED flag in the Writeback if set and
1083 // discard the CleanEvict by returning true.
1084 wbPkt->clearBlockCached();
1085
1086 // A clean evict does not need to access the data array
1087 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1088
1089 return true;
1090 } else {
1091 assert(pkt->cmd == MemCmd::WritebackDirty);
1092 // Dirty writeback from above trumps our clean
1093 // writeback... discard here
1094 // Note: markInService will remove entry from writeback buffer.
1095 markInService(wb_entry);
1096 delete wbPkt;
1097 }
1098 }
1099 }
1100
1101 // Writeback handling is special case. We can write the block into
1102 // the cache without having a writeable copy (or any copy at all).
1103 if (pkt->isWriteback()) {
1104 assert(blkSize == pkt->getSize());
1105
1106 // we could get a clean writeback while we are having
1107 // outstanding accesses to a block, do the simple thing for
1108 // now and drop the clean writeback so that we do not upset
1109 // any ordering/decisions about ownership already taken
1110 if (pkt->cmd == MemCmd::WritebackClean &&
1111 mshrQueue.findMatch(pkt->getAddr(), pkt->isSecure())) {
1112 DPRINTF(Cache, "Clean writeback %#llx to block with MSHR, "
1113 "dropping\n", pkt->getAddr());
1114
1115 // A writeback searches for the block, then writes the data.
1116 // As the writeback is being dropped, the data is not touched,
1117 // and we just had to wait for the time to find a match in the
1118 // MSHR. As of now assume a mshr queue search takes as long as
1119 // a tag lookup for simplicity.
1120 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1121
1122 return true;
1123 }
1124
1125 if (!blk) {
1126 // need to do a replacement
1127 blk = allocateBlock(pkt, writebacks);
1128 if (!blk) {
1129 // no replaceable block available: give up, fwd to next level.
1130 incMissCount(pkt);
1131
1132 // A writeback searches for the block, then writes the data.
1133 // As the block could not be found, it was a tag-only access.
1134 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1135
1136 return false;
1137 }
1138
1139 blk->status |= BlkReadable;
1140 } else if (compressor) {
1141 // This is an overwrite to an existing block, therefore we need
1142 // to check for data expansion (i.e., block was compressed with
1143 // a smaller size, and now it doesn't fit the entry anymore).
1144 // If that is the case we might need to evict blocks.
1145 if (!updateCompressionData(blk, pkt->getConstPtr<uint64_t>(),
1146 writebacks)) {
1147 // This is a failed data expansion (write), which happened
1148 // after finding the replacement entries and accessing the
1149 // block's data. There were no replaceable entries available
1150 // to make room for the expanded block, and since it does not
1151 // fit anymore and it has been properly updated to contain
1152 // the new data, forward it to the next level
1153 lat = calculateAccessLatency(blk, pkt->headerDelay,
1154 tag_latency);
1155 invalidateBlock(blk);
1156 return false;
1157 }
1158 }
1159
1160 // only mark the block dirty if we got a writeback command,
1161 // and leave it as is for a clean writeback
1162 if (pkt->cmd == MemCmd::WritebackDirty) {
1163 // TODO: the coherent cache can assert(!blk->isDirty());
1164 blk->status |= BlkDirty;
1165 }
1166 // if the packet does not have sharers, it is passing
1167 // writable, and we got the writeback in Modified or Exclusive
1168 // state, if not we are in the Owned or Shared state
1169 if (!pkt->hasSharers()) {
1170 blk->status |= BlkWritable;
1171 }
1172 // nothing else to do; writeback doesn't expect response
1173 assert(!pkt->needsResponse());
1174 pkt->writeDataToBlock(blk->data, blkSize);
1175 DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1176 incHitCount(pkt);
1177
1178 // A writeback searches for the block, then writes the data
1179 lat = calculateAccessLatency(blk, pkt->headerDelay, tag_latency);
1180
1181 // When the packet metadata arrives, the tag lookup will be done while
1182 // the payload is arriving. Then the block will be ready to access as
1183 // soon as the fill is done
1184 blk->setWhenReady(clockEdge(fillLatency) + pkt->headerDelay +
1185 std::max(cyclesToTicks(tag_latency), (uint64_t)pkt->payloadDelay));
1186
1187 return true;
1188 } else if (pkt->cmd == MemCmd::CleanEvict) {
1189 // A CleanEvict does not need to access the data array
1190 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1191
1192 if (blk) {
1193 // Found the block in the tags, need to stop CleanEvict from
1194 // propagating further down the hierarchy. Returning true will
1195 // treat the CleanEvict like a satisfied write request and delete
1196 // it.
1197 return true;
1198 }
1199 // We didn't find the block here, propagate the CleanEvict further
1200 // down the memory hierarchy. Returning false will treat the CleanEvict
1201 // like a Writeback which could not find a replaceable block so has to
1202 // go to next level.
1203 return false;
1204 } else if (pkt->cmd == MemCmd::WriteClean) {
1205 // WriteClean handling is a special case. We can allocate a
1206 // block directly if it doesn't exist and we can update the
1207 // block immediately. The WriteClean transfers the ownership
1208 // of the block as well.
1209 assert(blkSize == pkt->getSize());
1210
1211 if (!blk) {
1212 if (pkt->writeThrough()) {
1213 // A writeback searches for the block, then writes the data.
1214 // As the block could not be found, it was a tag-only access.
1215 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1216
1217 // if this is a write through packet, we don't try to
1218 // allocate if the block is not present
1219 return false;
1220 } else {
1221 // a writeback that misses needs to allocate a new block
1222 blk = allocateBlock(pkt, writebacks);
1223 if (!blk) {
1224 // no replaceable block available: give up, fwd to
1225 // next level.
1226 incMissCount(pkt);
1227
1228 // A writeback searches for the block, then writes the
1229 // data. As the block could not be found, it was a tag-only
1230 // access.
1231 lat = calculateTagOnlyLatency(pkt->headerDelay,
1232 tag_latency);
1233
1234 return false;
1235 }
1236
1237 blk->status |= BlkReadable;
1238 }
1239 } else if (compressor) {
1240 // This is an overwrite to an existing block, therefore we need
1241 // to check for data expansion (i.e., block was compressed with
1242 // a smaller size, and now it doesn't fit the entry anymore).
1243 // If that is the case we might need to evict blocks.
1244 if (!updateCompressionData(blk, pkt->getConstPtr<uint64_t>(),
1245 writebacks)) {
1246 // This is a failed data expansion (write), which happened
1247 // after finding the replacement entries and accessing the
1248 // block's data. There were no replaceable entries available
1249 // to make room for the expanded block, and since it does not
1250 // fit anymore and it has been properly updated to contain
1251 // the new data, forward it to the next level
1252 lat = calculateAccessLatency(blk, pkt->headerDelay,
1253 tag_latency);
1254 invalidateBlock(blk);
1255 return false;
1256 }
1257 }
1258
1259 // at this point either this is a writeback or a write-through
1260 // write clean operation and the block is already in this
1261 // cache, we need to update the data and the block flags
1262 assert(blk);
1263 // TODO: the coherent cache can assert(!blk->isDirty());
1264 if (!pkt->writeThrough()) {
1265 blk->status |= BlkDirty;
1266 }
1267 // nothing else to do; writeback doesn't expect response
1268 assert(!pkt->needsResponse());
1269 pkt->writeDataToBlock(blk->data, blkSize);
1270 DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1271
1272 incHitCount(pkt);
1273
1274 // A writeback searches for the block, then writes the data
1275 lat = calculateAccessLatency(blk, pkt->headerDelay, tag_latency);
1276
1277 // When the packet metadata arrives, the tag lookup will be done while
1278 // the payload is arriving. Then the block will be ready to access as
1279 // soon as the fill is done
1280 blk->setWhenReady(clockEdge(fillLatency) + pkt->headerDelay +
1281 std::max(cyclesToTicks(tag_latency), (uint64_t)pkt->payloadDelay));
1282
1283 // If this a write-through packet it will be sent to cache below
1284 return !pkt->writeThrough();
1285 } else if (blk && (pkt->needsWritable() ? blk->isWritable() :
1286 blk->isReadable())) {
1287 // OK to satisfy access
1288 incHitCount(pkt);
1289
1290 // Calculate access latency based on the need to access the data array
1291 if (pkt->isRead() || pkt->isWrite()) {
1292 lat = calculateAccessLatency(blk, pkt->headerDelay, tag_latency);
1293
1294 // When a block is compressed, it must first be decompressed
1295 // before being read. This adds to the access latency.
1296 if (compressor && pkt->isRead()) {
1297 lat += compressor->getDecompressionLatency(blk);
1298 }
1299 } else {
1300 lat = calculateTagOnlyLatency(pkt->headerDelay, tag_latency);
1301 }
1302
1303 satisfyRequest(pkt, blk);
1304 maintainClusivity(pkt->fromCache(), blk);
1305
1306 return true;
1307 }
1308
1309 // Can't satisfy access normally... either no block (blk == nullptr)
1310 // or have block but need writable
1311
1312 incMissCount(pkt);
1313
1314 lat = calculateAccessLatency(blk, pkt->headerDelay, tag_latency);
1315
1316 if (!blk && pkt->isLLSC() && pkt->isWrite()) {
1317 // complete miss on store conditional... just give up now
1318 pkt->req->setExtraData(0);
1319 return true;
1320 }
1321
1322 return false;
1323}
1324
1325void
1326BaseCache::maintainClusivity(bool from_cache, CacheBlk *blk)
1327{
1328 if (from_cache && blk && blk->isValid() && !blk->isDirty() &&
1329 clusivity == Enums::mostly_excl) {
1330 // if we have responded to a cache, and our block is still
1331 // valid, but not dirty, and this cache is mostly exclusive
1332 // with respect to the cache above, drop the block
1333 invalidateBlock(blk);
1334 }
1335}
1336
1337CacheBlk*
1338BaseCache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks,
1339 bool allocate)
1340{
1341 assert(pkt->isResponse());
1342 Addr addr = pkt->getAddr();
1343 bool is_secure = pkt->isSecure();
1344#if TRACING_ON
1345 CacheBlk::State old_state = blk ? blk->status : 0;
1346#endif
1347
1348 // When handling a fill, we should have no writes to this line.
1349 assert(addr == pkt->getBlockAddr(blkSize));
1350 assert(!writeBuffer.findMatch(addr, is_secure));
1351
1352 if (!blk) {
1353 // better have read new data...
1354 assert(pkt->hasData() || pkt->cmd == MemCmd::InvalidateResp);
1355
1356 // need to do a replacement if allocating, otherwise we stick
1357 // with the temporary storage
1358 blk = allocate ? allocateBlock(pkt, writebacks) : nullptr;
1359
1360 if (!blk) {
1361 // No replaceable block or a mostly exclusive
1362 // cache... just use temporary storage to complete the
1363 // current request and then get rid of it
1364 blk = tempBlock;
1365 tempBlock->insert(addr, is_secure);
1366 DPRINTF(Cache, "using temp block for %#llx (%s)\n", addr,
1367 is_secure ? "s" : "ns");
1368 }
1369 } else {
1370 // existing block... probably an upgrade
1371 // don't clear block status... if block is already dirty we
1372 // don't want to lose that
1373 }
1374
1375 // Block is guaranteed to be valid at this point
1376 assert(blk->isValid());
1377 assert(blk->isSecure() == is_secure);
1378 assert(regenerateBlkAddr(blk) == addr);
1379
1380 blk->status |= BlkReadable;
1381
1382 // sanity check for whole-line writes, which should always be
1383 // marked as writable as part of the fill, and then later marked
1384 // dirty as part of satisfyRequest
1385 if (pkt->cmd == MemCmd::InvalidateResp) {
1386 assert(!pkt->hasSharers());
1387 }
1388
1389 // here we deal with setting the appropriate state of the line,
1390 // and we start by looking at the hasSharers flag, and ignore the
1391 // cacheResponding flag (normally signalling dirty data) if the
1392 // packet has sharers, thus the line is never allocated as Owned
1393 // (dirty but not writable), and always ends up being either
1394 // Shared, Exclusive or Modified, see Packet::setCacheResponding
1395 // for more details
1396 if (!pkt->hasSharers()) {
1397 // we could get a writable line from memory (rather than a
1398 // cache) even in a read-only cache, note that we set this bit
1399 // even for a read-only cache, possibly revisit this decision
1400 blk->status |= BlkWritable;
1401
1402 // check if we got this via cache-to-cache transfer (i.e., from a
1403 // cache that had the block in Modified or Owned state)
1404 if (pkt->cacheResponding()) {
1405 // we got the block in Modified state, and invalidated the
1406 // owners copy
1407 blk->status |= BlkDirty;
1408
1409 chatty_assert(!isReadOnly, "Should never see dirty snoop response "
1410 "in read-only cache %s\n", name());
1411
1412 } else if (pkt->cmd.isSWPrefetch() && pkt->needsWritable()) {
1413 // All other copies of the block were invalidated and we
1414 // have an exclusive copy.
1415
1416 // The coherence protocol assumes that if we fetched an
1417 // exclusive copy of the block, we have the intention to
1418 // modify it. Therefore the MSHR for the PrefetchExReq has
1419 // been the point of ordering and this cache has commited
1420 // to respond to snoops for the block.
1421 //
1422 // In most cases this is true anyway - a PrefetchExReq
1423 // will be followed by a WriteReq. However, if that
1424 // doesn't happen, the block is not marked as dirty and
1425 // the cache doesn't respond to snoops that has committed
1426 // to do so.
1427 //
1428 // To avoid deadlocks in cases where there is a snoop
1429 // between the PrefetchExReq and the expected WriteReq, we
1430 // proactively mark the block as Dirty.
1431
1432 blk->status |= BlkDirty;
1433
1434 panic_if(!isReadOnly, "Prefetch exclusive requests from read-only "
1435 "cache %s\n", name());
1436 }
1437 }
1438
1439 DPRINTF(Cache, "Block addr %#llx (%s) moving from state %x to %s\n",
1440 addr, is_secure ? "s" : "ns", old_state, blk->print());
1441
1442 // if we got new data, copy it in (checking for a read response
1443 // and a response that has data is the same in the end)
1444 if (pkt->isRead()) {
1445 // sanity checks
1446 assert(pkt->hasData());
1447 assert(pkt->getSize() == blkSize);
1448
1449 pkt->writeDataToBlock(blk->data, blkSize);
1450 }
1451 // The block will be ready when the payload arrives and the fill is done
1452 blk->setWhenReady(clockEdge(fillLatency) + pkt->headerDelay +
1453 pkt->payloadDelay);
1454
1455 return blk;
1456}
1457
1458CacheBlk*
1459BaseCache::allocateBlock(const PacketPtr pkt, PacketList &writebacks)
1460{
1461 // Get address
1462 const Addr addr = pkt->getAddr();
1463
1464 // Get secure bit
1465 const bool is_secure = pkt->isSecure();
1466
1467 // Block size and compression related access latency. Only relevant if
1468 // using a compressor, otherwise there is no extra delay, and the block
1469 // is fully sized
1470 std::size_t blk_size_bits = blkSize*8;
1471 Cycles compression_lat = Cycles(0);
1472 Cycles decompression_lat = Cycles(0);
1473
1474 // If a compressor is being used, it is called to compress data before
1475 // insertion. Although in Gem5 the data is stored uncompressed, even if a
1476 // compressor is used, the compression/decompression methods are called to
1477 // calculate the amount of extra cycles needed to read or write compressed
1478 // blocks.
1479 if (compressor) {
1480 compressor->compress(pkt->getConstPtr<uint64_t>(), compression_lat,
1481 decompression_lat, blk_size_bits);
1482 }
1483
1484 // Find replacement victim
1485 std::vector<CacheBlk*> evict_blks;
1486 CacheBlk *victim = tags->findVictim(addr, is_secure, blk_size_bits,
1487 evict_blks);
1488
1489 // It is valid to return nullptr if there is no victim
1490 if (!victim)
1491 return nullptr;
1492
1493 // Print victim block's information
1494 DPRINTF(CacheRepl, "Replacement victim: %s\n", victim->print());
1495
1496 // Check for transient state allocations. If any of the entries listed
1497 // for eviction has a transient state, the allocation fails
1498 bool replacement = false;
1499 for (const auto& blk : evict_blks) {
1500 if (blk->isValid()) {
1501 replacement = true;
1502
1503 Addr repl_addr = regenerateBlkAddr(blk);
1504 MSHR *repl_mshr = mshrQueue.findMatch(repl_addr, blk->isSecure());
1505 if (repl_mshr) {
1506 // must be an outstanding upgrade or clean request
1507 // on a block we're about to replace...
1508 assert((!blk->isWritable() && repl_mshr->needsWritable()) ||
1509 repl_mshr->isCleaning());
1510
1511 // too hard to replace block with transient state
1512 // allocation failed, block not inserted
1513 return nullptr;
1514 }
1515 }
1516 }
1517
1518 // The victim will be replaced by a new entry, so increase the replacement
1519 // counter if a valid block is being replaced
1520 if (replacement) {
1521 // Evict valid blocks associated to this victim block
1522 for (const auto& blk : evict_blks) {
1523 if (blk->isValid()) {
1524 DPRINTF(CacheRepl, "Evicting %s (%#llx) to make room for " \
1525 "%#llx (%s)\n", blk->print(), regenerateBlkAddr(blk),
1526 addr, is_secure);
1527
1528 if (blk->wasPrefetched()) {
1529 unusedPrefetches++;
1530 }
1531
1532 evictBlock(blk, writebacks);
1533 }
1534 }
1535
1536 replacements++;
1537 }
1538
1539 // If using a compressor, set compression data. This must be done before
1540 // block insertion, as compressed tags use this information.
1541 if (compressor) {
1542 compressor->setSizeBits(victim, blk_size_bits);
1543 compressor->setDecompressionLatency(victim, decompression_lat);
1544 }
1545
1546 // Insert new block at victimized entry
1547 tags->insertBlock(pkt, victim);
1548
1549 return victim;
1550}
1551
1552void
1553BaseCache::invalidateBlock(CacheBlk *blk)
1554{
1555 // If handling a block present in the Tags, let it do its invalidation
1556 // process, which will update stats and invalidate the block itself
1557 if (blk != tempBlock) {
1558 tags->invalidate(blk);
1559 } else {
1560 tempBlock->invalidate();
1561 }
1562}
1563
1564void
1565BaseCache::evictBlock(CacheBlk *blk, PacketList &writebacks)
1566{
1567 PacketPtr pkt = evictBlock(blk);
1568 if (pkt) {
1569 writebacks.push_back(pkt);
1570 }
1571}
1572
1573PacketPtr
1574BaseCache::writebackBlk(CacheBlk *blk)
1575{
1576 chatty_assert(!isReadOnly || writebackClean,
1577 "Writeback from read-only cache");
1578 assert(blk && blk->isValid() && (blk->isDirty() || writebackClean));
1579
1580 writebacks[Request::wbMasterId]++;
1581
1582 RequestPtr req = std::make_shared<Request>(
1583 regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1584
1585 if (blk->isSecure())
1586 req->setFlags(Request::SECURE);
1587
1588 req->taskId(blk->task_id);
1589
1590 PacketPtr pkt =
1591 new Packet(req, blk->isDirty() ?
1592 MemCmd::WritebackDirty : MemCmd::WritebackClean);
1593
1594 DPRINTF(Cache, "Create Writeback %s writable: %d, dirty: %d\n",
1595 pkt->print(), blk->isWritable(), blk->isDirty());
1596
1597 if (blk->isWritable()) {
1598 // not asserting shared means we pass the block in modified
1599 // state, mark our own block non-writeable
1600 blk->status &= ~BlkWritable;
1601 } else {
1602 // we are in the Owned state, tell the receiver
1603 pkt->setHasSharers();
1604 }
1605
1606 // make sure the block is not marked dirty
1607 blk->status &= ~BlkDirty;
1608
1609 pkt->allocate();
1610 pkt->setDataFromBlock(blk->data, blkSize);
1611
1612 // When a block is compressed, it must first be decompressed before being
1613 // sent for writeback.
1614 if (compressor) {
1615 pkt->payloadDelay = compressor->getDecompressionLatency(blk);
1616 }
1617
1618 return pkt;
1619}
1620
1621PacketPtr
1622BaseCache::writecleanBlk(CacheBlk *blk, Request::Flags dest, PacketId id)
1623{
1624 RequestPtr req = std::make_shared<Request>(
1625 regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1626
1627 if (blk->isSecure()) {
1628 req->setFlags(Request::SECURE);
1629 }
1630 req->taskId(blk->task_id);
1631
1632 PacketPtr pkt = new Packet(req, MemCmd::WriteClean, blkSize, id);
1633
1634 if (dest) {
1635 req->setFlags(dest);
1636 pkt->setWriteThrough();
1637 }
1638
1639 DPRINTF(Cache, "Create %s writable: %d, dirty: %d\n", pkt->print(),
1640 blk->isWritable(), blk->isDirty());
1641
1642 if (blk->isWritable()) {
1643 // not asserting shared means we pass the block in modified
1644 // state, mark our own block non-writeable
1645 blk->status &= ~BlkWritable;
1646 } else {
1647 // we are in the Owned state, tell the receiver
1648 pkt->setHasSharers();
1649 }
1650
1651 // make sure the block is not marked dirty
1652 blk->status &= ~BlkDirty;
1653
1654 pkt->allocate();
1655 pkt->setDataFromBlock(blk->data, blkSize);
1656
1657 // When a block is compressed, it must first be decompressed before being
1658 // sent for writeback.
1659 if (compressor) {
1660 pkt->payloadDelay = compressor->getDecompressionLatency(blk);
1661 }
1662
1663 return pkt;
1664}
1665
1666
1667void
1668BaseCache::memWriteback()
1669{
1670 tags->forEachBlk([this](CacheBlk &blk) { writebackVisitor(blk); });
1671}
1672
1673void
1674BaseCache::memInvalidate()
1675{
1676 tags->forEachBlk([this](CacheBlk &blk) { invalidateVisitor(blk); });
1677}
1678
1679bool
1680BaseCache::isDirty() const
1681{
1682 return tags->anyBlk([](CacheBlk &blk) { return blk.isDirty(); });
1683}
1684
1685bool
1686BaseCache::coalesce() const
1687{
1688 return writeAllocator && writeAllocator->coalesce();
1689}
1690
1691void
1692BaseCache::writebackVisitor(CacheBlk &blk)
1693{
1694 if (blk.isDirty()) {
1695 assert(blk.isValid());
1696
1697 RequestPtr request = std::make_shared<Request>(
1698 regenerateBlkAddr(&blk), blkSize, 0, Request::funcMasterId);
1699
1700 request->taskId(blk.task_id);
1701 if (blk.isSecure()) {
1702 request->setFlags(Request::SECURE);
1703 }
1704
1705 Packet packet(request, MemCmd::WriteReq);
1706 packet.dataStatic(blk.data);
1707
1708 memSidePort.sendFunctional(&packet);
1709
1710 blk.status &= ~BlkDirty;
1711 }
1712}
1713
1714void
1715BaseCache::invalidateVisitor(CacheBlk &blk)
1716{
1717 if (blk.isDirty())
1718 warn_once("Invalidating dirty cache lines. " \
1719 "Expect things to break.\n");
1720
1721 if (blk.isValid()) {
1722 assert(!blk.isDirty());
1723 invalidateBlock(&blk);
1724 }
1725}
1726
1727Tick
1728BaseCache::nextQueueReadyTime() const
1729{
1730 Tick nextReady = std::min(mshrQueue.nextReadyTime(),
1731 writeBuffer.nextReadyTime());
1732
1733 // Don't signal prefetch ready time if no MSHRs available
1734 // Will signal once enoguh MSHRs are deallocated
1735 if (prefetcher && mshrQueue.canPrefetch()) {
1736 nextReady = std::min(nextReady,
1737 prefetcher->nextPrefetchReadyTime());
1738 }
1739
1740 return nextReady;
1741}
1742
1743
1744bool
1745BaseCache::sendMSHRQueuePacket(MSHR* mshr)
1746{
1747 assert(mshr);
1748
1749 // use request from 1st target
1750 PacketPtr tgt_pkt = mshr->getTarget()->pkt;
1751
1752 DPRINTF(Cache, "%s: MSHR %s\n", __func__, tgt_pkt->print());
1753
1754 // if the cache is in write coalescing mode or (additionally) in
1755 // no allocation mode, and we have a write packet with an MSHR
1756 // that is not a whole-line write (due to incompatible flags etc),
1757 // then reset the write mode
1758 if (writeAllocator && writeAllocator->coalesce() && tgt_pkt->isWrite()) {
1759 if (!mshr->isWholeLineWrite()) {
1760 // if we are currently write coalescing, hold on the
1761 // MSHR as many cycles extra as we need to completely
1762 // write a cache line
1763 if (writeAllocator->delay(mshr->blkAddr)) {
1764 Tick delay = blkSize / tgt_pkt->getSize() * clockPeriod();
1765 DPRINTF(CacheVerbose, "Delaying pkt %s %llu ticks to allow "
1766 "for write coalescing\n", tgt_pkt->print(), delay);
1767 mshrQueue.delay(mshr, delay);
1768 return false;
1769 } else {
1770 writeAllocator->reset();
1771 }
1772 } else {
1773 writeAllocator->resetDelay(mshr->blkAddr);
1774 }
1775 }
1776
1777 CacheBlk *blk = tags->findBlock(mshr->blkAddr, mshr->isSecure);
1778
1779 // either a prefetch that is not present upstream, or a normal
1780 // MSHR request, proceed to get the packet to send downstream
1781 PacketPtr pkt = createMissPacket(tgt_pkt, blk, mshr->needsWritable(),
1782 mshr->isWholeLineWrite());
1783
1784 mshr->isForward = (pkt == nullptr);
1785
1786 if (mshr->isForward) {
1787 // not a cache block request, but a response is expected
1788 // make copy of current packet to forward, keep current
1789 // copy for response handling
1790 pkt = new Packet(tgt_pkt, false, true);
1791 assert(!pkt->isWrite());
1792 }
1793
1794 // play it safe and append (rather than set) the sender state,
1795 // as forwarded packets may already have existing state
1796 pkt->pushSenderState(mshr);
1797
1798 if (pkt->isClean() && blk && blk->isDirty()) {
1799 // A cache clean opearation is looking for a dirty block. Mark
1800 // the packet so that the destination xbar can determine that
1801 // there will be a follow-up write packet as well.
1802 pkt->setSatisfied();
1803 }
1804
1805 if (!memSidePort.sendTimingReq(pkt)) {
1806 // we are awaiting a retry, but we
1807 // delete the packet and will be creating a new packet
1808 // when we get the opportunity
1809 delete pkt;
1810
1811 // note that we have now masked any requestBus and
1812 // schedSendEvent (we will wait for a retry before
1813 // doing anything), and this is so even if we do not
1814 // care about this packet and might override it before
1815 // it gets retried
1816 return true;
1817 } else {
1818 // As part of the call to sendTimingReq the packet is
1819 // forwarded to all neighbouring caches (and any caches
1820 // above them) as a snoop. Thus at this point we know if
1821 // any of the neighbouring caches are responding, and if
1822 // so, we know it is dirty, and we can determine if it is
1823 // being passed as Modified, making our MSHR the ordering
1824 // point
1825 bool pending_modified_resp = !pkt->hasSharers() &&
1826 pkt->cacheResponding();
1827 markInService(mshr, pending_modified_resp);
1828
1829 if (pkt->isClean() && blk && blk->isDirty()) {
1830 // A cache clean opearation is looking for a dirty
1831 // block. If a dirty block is encountered a WriteClean
1832 // will update any copies to the path to the memory
1833 // until the point of reference.
1834 DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
1835 __func__, pkt->print(), blk->print());
1836 PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(),
1837 pkt->id);
1838 PacketList writebacks;
1839 writebacks.push_back(wb_pkt);
1840 doWritebacks(writebacks, 0);
1841 }
1842
1843 return false;
1844 }
1845}
1846
1847bool
1848BaseCache::sendWriteQueuePacket(WriteQueueEntry* wq_entry)
1849{
1850 assert(wq_entry);
1851
1852 // always a single target for write queue entries
1853 PacketPtr tgt_pkt = wq_entry->getTarget()->pkt;
1854
1855 DPRINTF(Cache, "%s: write %s\n", __func__, tgt_pkt->print());
1856
1857 // forward as is, both for evictions and uncacheable writes
1858 if (!memSidePort.sendTimingReq(tgt_pkt)) {
1859 // note that we have now masked any requestBus and
1860 // schedSendEvent (we will wait for a retry before
1861 // doing anything), and this is so even if we do not
1862 // care about this packet and might override it before
1863 // it gets retried
1864 return true;
1865 } else {
1866 markInService(wq_entry);
1867 return false;
1868 }
1869}
1870
1871void
1872BaseCache::serialize(CheckpointOut &cp) const
1873{
1874 bool dirty(isDirty());
1875
1876 if (dirty) {
1877 warn("*** The cache still contains dirty data. ***\n");
1878 warn(" Make sure to drain the system using the correct flags.\n");
1879 warn(" This checkpoint will not restore correctly " \
1880 "and dirty data in the cache will be lost!\n");
1881 }
1882
1883 // Since we don't checkpoint the data in the cache, any dirty data
1884 // will be lost when restoring from a checkpoint of a system that
1885 // wasn't drained properly. Flag the checkpoint as invalid if the
1886 // cache contains dirty data.
1887 bool bad_checkpoint(dirty);
1888 SERIALIZE_SCALAR(bad_checkpoint);
1889}
1890
1891void
1892BaseCache::unserialize(CheckpointIn &cp)
1893{
1894 bool bad_checkpoint;
1895 UNSERIALIZE_SCALAR(bad_checkpoint);
1896 if (bad_checkpoint) {
1897 fatal("Restoring from checkpoints with dirty caches is not "
1898 "supported in the classic memory system. Please remove any "
1899 "caches or drain them properly before taking checkpoints.\n");
1900 }
1901}
1902
1903void
1904BaseCache::regStats()
1905{
1906 ClockedObject::regStats();
1907
1908 using namespace Stats;
1909
1910 // Hit statistics
1911 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1912 MemCmd cmd(access_idx);
1913 const string &cstr = cmd.toString();
1914
1915 hits[access_idx]
1916 .init(system->maxMasters())
1917 .name(name() + "." + cstr + "_hits")
1918 .desc("number of " + cstr + " hits")
1919 .flags(total | nozero | nonan)
1920 ;
1921 for (int i = 0; i < system->maxMasters(); i++) {
1922 hits[access_idx].subname(i, system->getMasterName(i));
1923 }
1924 }
1925
1926// These macros make it easier to sum the right subset of commands and
1927// to change the subset of commands that are considered "demand" vs
1928// "non-demand"
1929#define SUM_DEMAND(s) \
1930 (s[MemCmd::ReadReq] + s[MemCmd::WriteReq] + s[MemCmd::WriteLineReq] + \
1931 s[MemCmd::ReadExReq] + s[MemCmd::ReadCleanReq] + s[MemCmd::ReadSharedReq])
1932
1933// should writebacks be included here? prior code was inconsistent...
1934#define SUM_NON_DEMAND(s) \
1935 (s[MemCmd::SoftPFReq] + s[MemCmd::HardPFReq] + s[MemCmd::SoftPFExReq])
1936
1937 demandHits
1938 .name(name() + ".demand_hits")
1939 .desc("number of demand (read+write) hits")
1940 .flags(total | nozero | nonan)
1941 ;
1942 demandHits = SUM_DEMAND(hits);
1943 for (int i = 0; i < system->maxMasters(); i++) {
1944 demandHits.subname(i, system->getMasterName(i));
1945 }
1946
1947 overallHits
1948 .name(name() + ".overall_hits")
1949 .desc("number of overall hits")
1950 .flags(total | nozero | nonan)
1951 ;
1952 overallHits = demandHits + SUM_NON_DEMAND(hits);
1953 for (int i = 0; i < system->maxMasters(); i++) {
1954 overallHits.subname(i, system->getMasterName(i));
1955 }
1956
1957 // Miss statistics
1958 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1959 MemCmd cmd(access_idx);
1960 const string &cstr = cmd.toString();
1961
1962 misses[access_idx]
1963 .init(system->maxMasters())
1964 .name(name() + "." + cstr + "_misses")
1965 .desc("number of " + cstr + " misses")
1966 .flags(total | nozero | nonan)
1967 ;
1968 for (int i = 0; i < system->maxMasters(); i++) {
1969 misses[access_idx].subname(i, system->getMasterName(i));
1970 }
1971 }
1972
1973 demandMisses
1974 .name(name() + ".demand_misses")
1975 .desc("number of demand (read+write) misses")
1976 .flags(total | nozero | nonan)
1977 ;
1978 demandMisses = SUM_DEMAND(misses);
1979 for (int i = 0; i < system->maxMasters(); i++) {
1980 demandMisses.subname(i, system->getMasterName(i));
1981 }
1982
1983 overallMisses
1984 .name(name() + ".overall_misses")
1985 .desc("number of overall misses")
1986 .flags(total | nozero | nonan)
1987 ;
1988 overallMisses = demandMisses + SUM_NON_DEMAND(misses);
1989 for (int i = 0; i < system->maxMasters(); i++) {
1990 overallMisses.subname(i, system->getMasterName(i));
1991 }
1992
1993 // Miss latency statistics
1994 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1995 MemCmd cmd(access_idx);
1996 const string &cstr = cmd.toString();
1997
1998 missLatency[access_idx]
1999 .init(system->maxMasters())
2000 .name(name() + "." + cstr + "_miss_latency")
2001 .desc("number of " + cstr + " miss cycles")
2002 .flags(total | nozero | nonan)
2003 ;
2004 for (int i = 0; i < system->maxMasters(); i++) {
2005 missLatency[access_idx].subname(i, system->getMasterName(i));
2006 }
2007 }
2008
2009 demandMissLatency
2010 .name(name() + ".demand_miss_latency")
2011 .desc("number of demand (read+write) miss cycles")
2012 .flags(total | nozero | nonan)
2013 ;
2014 demandMissLatency = SUM_DEMAND(missLatency);
2015 for (int i = 0; i < system->maxMasters(); i++) {
2016 demandMissLatency.subname(i, system->getMasterName(i));
2017 }
2018
2019 overallMissLatency
2020 .name(name() + ".overall_miss_latency")
2021 .desc("number of overall miss cycles")
2022 .flags(total | nozero | nonan)
2023 ;
2024 overallMissLatency = demandMissLatency + SUM_NON_DEMAND(missLatency);
2025 for (int i = 0; i < system->maxMasters(); i++) {
2026 overallMissLatency.subname(i, system->getMasterName(i));
2027 }
2028
2029 // access formulas
2030 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2031 MemCmd cmd(access_idx);
2032 const string &cstr = cmd.toString();
2033
2034 accesses[access_idx]
2035 .name(name() + "." + cstr + "_accesses")
2036 .desc("number of " + cstr + " accesses(hits+misses)")
2037 .flags(total | nozero | nonan)
2038 ;
2039 accesses[access_idx] = hits[access_idx] + misses[access_idx];
2040
2041 for (int i = 0; i < system->maxMasters(); i++) {
2042 accesses[access_idx].subname(i, system->getMasterName(i));
2043 }
2044 }
2045
2046 demandAccesses
2047 .name(name() + ".demand_accesses")
2048 .desc("number of demand (read+write) accesses")
2049 .flags(total | nozero | nonan)
2050 ;
2051 demandAccesses = demandHits + demandMisses;
2052 for (int i = 0; i < system->maxMasters(); i++) {
2053 demandAccesses.subname(i, system->getMasterName(i));
2054 }
2055
2056 overallAccesses
2057 .name(name() + ".overall_accesses")
2058 .desc("number of overall (read+write) accesses")
2059 .flags(total | nozero | nonan)
2060 ;
2061 overallAccesses = overallHits + overallMisses;
2062 for (int i = 0; i < system->maxMasters(); i++) {
2063 overallAccesses.subname(i, system->getMasterName(i));
2064 }
2065
2066 // miss rate formulas
2067 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2068 MemCmd cmd(access_idx);
2069 const string &cstr = cmd.toString();
2070
2071 missRate[access_idx]
2072 .name(name() + "." + cstr + "_miss_rate")
2073 .desc("miss rate for " + cstr + " accesses")
2074 .flags(total | nozero | nonan)
2075 ;
2076 missRate[access_idx] = misses[access_idx] / accesses[access_idx];
2077
2078 for (int i = 0; i < system->maxMasters(); i++) {
2079 missRate[access_idx].subname(i, system->getMasterName(i));
2080 }
2081 }
2082
2083 demandMissRate
2084 .name(name() + ".demand_miss_rate")
2085 .desc("miss rate for demand accesses")
2086 .flags(total | nozero | nonan)
2087 ;
2088 demandMissRate = demandMisses / demandAccesses;
2089 for (int i = 0; i < system->maxMasters(); i++) {
2090 demandMissRate.subname(i, system->getMasterName(i));
2091 }
2092
2093 overallMissRate
2094 .name(name() + ".overall_miss_rate")
2095 .desc("miss rate for overall accesses")
2096 .flags(total | nozero | nonan)
2097 ;
2098 overallMissRate = overallMisses / overallAccesses;
2099 for (int i = 0; i < system->maxMasters(); i++) {
2100 overallMissRate.subname(i, system->getMasterName(i));
2101 }
2102
2103 // miss latency formulas
2104 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2105 MemCmd cmd(access_idx);
2106 const string &cstr = cmd.toString();
2107
2108 avgMissLatency[access_idx]
2109 .name(name() + "." + cstr + "_avg_miss_latency")
2110 .desc("average " + cstr + " miss latency")
2111 .flags(total | nozero | nonan)
2112 ;
2113 avgMissLatency[access_idx] =
2114 missLatency[access_idx] / misses[access_idx];
2115
2116 for (int i = 0; i < system->maxMasters(); i++) {
2117 avgMissLatency[access_idx].subname(i, system->getMasterName(i));
2118 }
2119 }
2120
2121 demandAvgMissLatency
2122 .name(name() + ".demand_avg_miss_latency")
2123 .desc("average overall miss latency")
2124 .flags(total | nozero | nonan)
2125 ;
2126 demandAvgMissLatency = demandMissLatency / demandMisses;
2127 for (int i = 0; i < system->maxMasters(); i++) {
2128 demandAvgMissLatency.subname(i, system->getMasterName(i));
2129 }
2130
2131 overallAvgMissLatency
2132 .name(name() + ".overall_avg_miss_latency")
2133 .desc("average overall miss latency")
2134 .flags(total | nozero | nonan)
2135 ;
2136 overallAvgMissLatency = overallMissLatency / overallMisses;
2137 for (int i = 0; i < system->maxMasters(); i++) {
2138 overallAvgMissLatency.subname(i, system->getMasterName(i));
2139 }
2140
2141 blocked_cycles.init(NUM_BLOCKED_CAUSES);
2142 blocked_cycles
2143 .name(name() + ".blocked_cycles")
2144 .desc("number of cycles access was blocked")
2145 .subname(Blocked_NoMSHRs, "no_mshrs")
2146 .subname(Blocked_NoTargets, "no_targets")
2147 ;
2148
2149
2150 blocked_causes.init(NUM_BLOCKED_CAUSES);
2151 blocked_causes
2152 .name(name() + ".blocked")
2153 .desc("number of cycles access was blocked")
2154 .subname(Blocked_NoMSHRs, "no_mshrs")
2155 .subname(Blocked_NoTargets, "no_targets")
2156 ;
2157
2158 avg_blocked
2159 .name(name() + ".avg_blocked_cycles")
2160 .desc("average number of cycles each access was blocked")
2161 .subname(Blocked_NoMSHRs, "no_mshrs")
2162 .subname(Blocked_NoTargets, "no_targets")
2163 ;
2164
2165 avg_blocked = blocked_cycles / blocked_causes;
2166
2167 unusedPrefetches
2168 .name(name() + ".unused_prefetches")
2169 .desc("number of HardPF blocks evicted w/o reference")
2170 .flags(nozero)
2171 ;
2172
2173 writebacks
2174 .init(system->maxMasters())
2175 .name(name() + ".writebacks")
2176 .desc("number of writebacks")
2177 .flags(total | nozero | nonan)
2178 ;
2179 for (int i = 0; i < system->maxMasters(); i++) {
2180 writebacks.subname(i, system->getMasterName(i));
2181 }
2182
2183 // MSHR statistics
2184 // MSHR hit statistics
2185 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2186 MemCmd cmd(access_idx);
2187 const string &cstr = cmd.toString();
2188
2189 mshr_hits[access_idx]
2190 .init(system->maxMasters())
2191 .name(name() + "." + cstr + "_mshr_hits")
2192 .desc("number of " + cstr + " MSHR hits")
2193 .flags(total | nozero | nonan)
2194 ;
2195 for (int i = 0; i < system->maxMasters(); i++) {
2196 mshr_hits[access_idx].subname(i, system->getMasterName(i));
2197 }
2198 }
2199
2200 demandMshrHits
2201 .name(name() + ".demand_mshr_hits")
2202 .desc("number of demand (read+write) MSHR hits")
2203 .flags(total | nozero | nonan)
2204 ;
2205 demandMshrHits = SUM_DEMAND(mshr_hits);
2206 for (int i = 0; i < system->maxMasters(); i++) {
2207 demandMshrHits.subname(i, system->getMasterName(i));
2208 }
2209
2210 overallMshrHits
2211 .name(name() + ".overall_mshr_hits")
2212 .desc("number of overall MSHR hits")
2213 .flags(total | nozero | nonan)
2214 ;
2215 overallMshrHits = demandMshrHits + SUM_NON_DEMAND(mshr_hits);
2216 for (int i = 0; i < system->maxMasters(); i++) {
2217 overallMshrHits.subname(i, system->getMasterName(i));
2218 }
2219
2220 // MSHR miss statistics
2221 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2222 MemCmd cmd(access_idx);
2223 const string &cstr = cmd.toString();
2224
2225 mshr_misses[access_idx]
2226 .init(system->maxMasters())
2227 .name(name() + "." + cstr + "_mshr_misses")
2228 .desc("number of " + cstr + " MSHR misses")
2229 .flags(total | nozero | nonan)
2230 ;
2231 for (int i = 0; i < system->maxMasters(); i++) {
2232 mshr_misses[access_idx].subname(i, system->getMasterName(i));
2233 }
2234 }
2235
2236 demandMshrMisses
2237 .name(name() + ".demand_mshr_misses")
2238 .desc("number of demand (read+write) MSHR misses")
2239 .flags(total | nozero | nonan)
2240 ;
2241 demandMshrMisses = SUM_DEMAND(mshr_misses);
2242 for (int i = 0; i < system->maxMasters(); i++) {
2243 demandMshrMisses.subname(i, system->getMasterName(i));
2244 }
2245
2246 overallMshrMisses
2247 .name(name() + ".overall_mshr_misses")
2248 .desc("number of overall MSHR misses")
2249 .flags(total | nozero | nonan)
2250 ;
2251 overallMshrMisses = demandMshrMisses + SUM_NON_DEMAND(mshr_misses);
2252 for (int i = 0; i < system->maxMasters(); i++) {
2253 overallMshrMisses.subname(i, system->getMasterName(i));
2254 }
2255
2256 // MSHR miss latency statistics
2257 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2258 MemCmd cmd(access_idx);
2259 const string &cstr = cmd.toString();
2260
2261 mshr_miss_latency[access_idx]
2262 .init(system->maxMasters())
2263 .name(name() + "." + cstr + "_mshr_miss_latency")
2264 .desc("number of " + cstr + " MSHR miss cycles")
2265 .flags(total | nozero | nonan)
2266 ;
2267 for (int i = 0; i < system->maxMasters(); i++) {
2268 mshr_miss_latency[access_idx].subname(i, system->getMasterName(i));
2269 }
2270 }
2271
2272 demandMshrMissLatency
2273 .name(name() + ".demand_mshr_miss_latency")
2274 .desc("number of demand (read+write) MSHR miss cycles")
2275 .flags(total | nozero | nonan)
2276 ;
2277 demandMshrMissLatency = SUM_DEMAND(mshr_miss_latency);
2278 for (int i = 0; i < system->maxMasters(); i++) {
2279 demandMshrMissLatency.subname(i, system->getMasterName(i));
2280 }
2281
2282 overallMshrMissLatency
2283 .name(name() + ".overall_mshr_miss_latency")
2284 .desc("number of overall MSHR miss cycles")
2285 .flags(total | nozero | nonan)
2286 ;
2287 overallMshrMissLatency =
2288 demandMshrMissLatency + SUM_NON_DEMAND(mshr_miss_latency);
2289 for (int i = 0; i < system->maxMasters(); i++) {
2290 overallMshrMissLatency.subname(i, system->getMasterName(i));
2291 }
2292
2293 // MSHR uncacheable statistics
2294 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2295 MemCmd cmd(access_idx);
2296 const string &cstr = cmd.toString();
2297
2298 mshr_uncacheable[access_idx]
2299 .init(system->maxMasters())
2300 .name(name() + "." + cstr + "_mshr_uncacheable")
2301 .desc("number of " + cstr + " MSHR uncacheable")
2302 .flags(total | nozero | nonan)
2303 ;
2304 for (int i = 0; i < system->maxMasters(); i++) {
2305 mshr_uncacheable[access_idx].subname(i, system->getMasterName(i));
2306 }
2307 }
2308
2309 overallMshrUncacheable
2310 .name(name() + ".overall_mshr_uncacheable_misses")
2311 .desc("number of overall MSHR uncacheable misses")
2312 .flags(total | nozero | nonan)
2313 ;
2314 overallMshrUncacheable =
2315 SUM_DEMAND(mshr_uncacheable) + SUM_NON_DEMAND(mshr_uncacheable);
2316 for (int i = 0; i < system->maxMasters(); i++) {
2317 overallMshrUncacheable.subname(i, system->getMasterName(i));
2318 }
2319
2320 // MSHR miss latency statistics
2321 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2322 MemCmd cmd(access_idx);
2323 const string &cstr = cmd.toString();
2324
2325 mshr_uncacheable_lat[access_idx]
2326 .init(system->maxMasters())
2327 .name(name() + "." + cstr + "_mshr_uncacheable_latency")
2328 .desc("number of " + cstr + " MSHR uncacheable cycles")
2329 .flags(total | nozero | nonan)
2330 ;
2331 for (int i = 0; i < system->maxMasters(); i++) {
2332 mshr_uncacheable_lat[access_idx].subname(
2333 i, system->getMasterName(i));
2334 }
2335 }
2336
2337 overallMshrUncacheableLatency
2338 .name(name() + ".overall_mshr_uncacheable_latency")
2339 .desc("number of overall MSHR uncacheable cycles")
2340 .flags(total | nozero | nonan)
2341 ;
2342 overallMshrUncacheableLatency =
2343 SUM_DEMAND(mshr_uncacheable_lat) +
2344 SUM_NON_DEMAND(mshr_uncacheable_lat);
2345 for (int i = 0; i < system->maxMasters(); i++) {
2346 overallMshrUncacheableLatency.subname(i, system->getMasterName(i));
2347 }
2348
2349 // MSHR miss rate formulas
2350 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2351 MemCmd cmd(access_idx);
2352 const string &cstr = cmd.toString();
2353
2354 mshrMissRate[access_idx]
2355 .name(name() + "." + cstr + "_mshr_miss_rate")
2356 .desc("mshr miss rate for " + cstr + " accesses")
2357 .flags(total | nozero | nonan)
2358 ;
2359 mshrMissRate[access_idx] =
2360 mshr_misses[access_idx] / accesses[access_idx];
2361
2362 for (int i = 0; i < system->maxMasters(); i++) {
2363 mshrMissRate[access_idx].subname(i, system->getMasterName(i));
2364 }
2365 }
2366
2367 demandMshrMissRate
2368 .name(name() + ".demand_mshr_miss_rate")
2369 .desc("mshr miss rate for demand accesses")
2370 .flags(total | nozero | nonan)
2371 ;
2372 demandMshrMissRate = demandMshrMisses / demandAccesses;
2373 for (int i = 0; i < system->maxMasters(); i++) {
2374 demandMshrMissRate.subname(i, system->getMasterName(i));
2375 }
2376
2377 overallMshrMissRate
2378 .name(name() + ".overall_mshr_miss_rate")
2379 .desc("mshr miss rate for overall accesses")
2380 .flags(total | nozero | nonan)
2381 ;
2382 overallMshrMissRate = overallMshrMisses / overallAccesses;
2383 for (int i = 0; i < system->maxMasters(); i++) {
2384 overallMshrMissRate.subname(i, system->getMasterName(i));
2385 }
2386
2387 // mshrMiss latency formulas
2388 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2389 MemCmd cmd(access_idx);
2390 const string &cstr = cmd.toString();
2391
2392 avgMshrMissLatency[access_idx]
2393 .name(name() + "." + cstr + "_avg_mshr_miss_latency")
2394 .desc("average " + cstr + " mshr miss latency")
2395 .flags(total | nozero | nonan)
2396 ;
2397 avgMshrMissLatency[access_idx] =
2398 mshr_miss_latency[access_idx] / mshr_misses[access_idx];
2399
2400 for (int i = 0; i < system->maxMasters(); i++) {
2401 avgMshrMissLatency[access_idx].subname(
2402 i, system->getMasterName(i));
2403 }
2404 }
2405
2406 demandAvgMshrMissLatency
2407 .name(name() + ".demand_avg_mshr_miss_latency")
2408 .desc("average overall mshr miss latency")
2409 .flags(total | nozero | nonan)
2410 ;
2411 demandAvgMshrMissLatency = demandMshrMissLatency / demandMshrMisses;
2412 for (int i = 0; i < system->maxMasters(); i++) {
2413 demandAvgMshrMissLatency.subname(i, system->getMasterName(i));
2414 }
2415
2416 overallAvgMshrMissLatency
2417 .name(name() + ".overall_avg_mshr_miss_latency")
2418 .desc("average overall mshr miss latency")
2419 .flags(total | nozero | nonan)
2420 ;
2421 overallAvgMshrMissLatency = overallMshrMissLatency / overallMshrMisses;
2422 for (int i = 0; i < system->maxMasters(); i++) {
2423 overallAvgMshrMissLatency.subname(i, system->getMasterName(i));
2424 }
2425
2426 // mshrUncacheable latency formulas
2427 for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2428 MemCmd cmd(access_idx);
2429 const string &cstr = cmd.toString();
2430
2431 avgMshrUncacheableLatency[access_idx]
2432 .name(name() + "." + cstr + "_avg_mshr_uncacheable_latency")
2433 .desc("average " + cstr + " mshr uncacheable latency")
2434 .flags(total | nozero | nonan)
2435 ;
2436 avgMshrUncacheableLatency[access_idx] =
2437 mshr_uncacheable_lat[access_idx] / mshr_uncacheable[access_idx];
2438
2439 for (int i = 0; i < system->maxMasters(); i++) {
2440 avgMshrUncacheableLatency[access_idx].subname(
2441 i, system->getMasterName(i));
2442 }
2443 }
2444
2445 overallAvgMshrUncacheableLatency
2446 .name(name() + ".overall_avg_mshr_uncacheable_latency")
2447 .desc("average overall mshr uncacheable latency")
2448 .flags(total | nozero | nonan)
2449 ;
2450 overallAvgMshrUncacheableLatency =
2451 overallMshrUncacheableLatency / overallMshrUncacheable;
2452 for (int i = 0; i < system->maxMasters(); i++) {
2453 overallAvgMshrUncacheableLatency.subname(i, system->getMasterName(i));
2454 }
2455
2456 replacements
2457 .name(name() + ".replacements")
2458 .desc("number of replacements")
2459 ;
2460
2461 dataExpansions
2462 .name(name() + ".data_expansions")
2463 .desc("number of data expansions")
2464 .flags(nozero | nonan)
2465 ;
2466}
2467
2468void
2469BaseCache::regProbePoints()
2470{
2471 ppHit = new ProbePointArg<PacketPtr>(this->getProbeManager(), "Hit");
2472 ppMiss = new ProbePointArg<PacketPtr>(this->getProbeManager(), "Miss");
2473 ppFill = new ProbePointArg<PacketPtr>(this->getProbeManager(), "Fill");
2474}
2475
2476///////////////
2477//
2478// CpuSidePort
2479//
2480///////////////
2481bool
2482BaseCache::CpuSidePort::recvTimingSnoopResp(PacketPtr pkt)
2483{
2484 // Snoops shouldn't happen when bypassing caches
2485 assert(!cache->system->bypassCaches());
2486
2487 assert(pkt->isResponse());
2488
2489 // Express snoop responses from master to slave, e.g., from L1 to L2
2490 cache->recvTimingSnoopResp(pkt);
2491 return true;
2492}
2493
2494
2495bool
2496BaseCache::CpuSidePort::tryTiming(PacketPtr pkt)
2497{
2498 if (cache->system->bypassCaches() || pkt->isExpressSnoop()) {
2499 // always let express snoop packets through even if blocked
2500 return true;
2501 } else if (blocked || mustSendRetry) {
2502 // either already committed to send a retry, or blocked
2503 mustSendRetry = true;
2504 return false;
2505 }
2506 mustSendRetry = false;
2507 return true;
2508}
2509
2510bool
2511BaseCache::CpuSidePort::recvTimingReq(PacketPtr pkt)
2512{
2513 assert(pkt->isRequest());
2514
2515 if (cache->system->bypassCaches()) {
2516 // Just forward the packet if caches are disabled.
2517 // @todo This should really enqueue the packet rather
2518 bool M5_VAR_USED success = cache->memSidePort.sendTimingReq(pkt);
2519 assert(success);
2520 return true;
2521 } else if (tryTiming(pkt)) {
2522 cache->recvTimingReq(pkt);
2523 return true;
2524 }
2525 return false;
2526}
2527
2528Tick
2529BaseCache::CpuSidePort::recvAtomic(PacketPtr pkt)
2530{
2531 if (cache->system->bypassCaches()) {
2532 // Forward the request if the system is in cache bypass mode.
2533 return cache->memSidePort.sendAtomic(pkt);
2534 } else {
2535 return cache->recvAtomic(pkt);
2536 }
2537}
2538
2539void
2540BaseCache::CpuSidePort::recvFunctional(PacketPtr pkt)
2541{
2542 if (cache->system->bypassCaches()) {
2543 // The cache should be flushed if we are in cache bypass mode,
2544 // so we don't need to check if we need to update anything.
2545 cache->memSidePort.sendFunctional(pkt);
2546 return;
2547 }
2548
2549 // functional request
2550 cache->functionalAccess(pkt, true);
2551}
2552
2553AddrRangeList
2554BaseCache::CpuSidePort::getAddrRanges() const
2555{
2556 return cache->getAddrRanges();
2557}
2558
2559
2560BaseCache::
2561CpuSidePort::CpuSidePort(const std::string &_name, BaseCache *_cache,
2562 const std::string &_label)
2563 : CacheSlavePort(_name, _cache, _label), cache(_cache)
2564{
2565}
2566
2567///////////////
2568//
2569// MemSidePort
2570//
2571///////////////
2572bool
2573BaseCache::MemSidePort::recvTimingResp(PacketPtr pkt)
2574{
2575 cache->recvTimingResp(pkt);
2576 return true;
2577}
2578
2579// Express snooping requests to memside port
2580void
2581BaseCache::MemSidePort::recvTimingSnoopReq(PacketPtr pkt)
2582{
2583 // Snoops shouldn't happen when bypassing caches
2584 assert(!cache->system->bypassCaches());
2585
2586 // handle snooping requests
2587 cache->recvTimingSnoopReq(pkt);
2588}
2589
2590Tick
2591BaseCache::MemSidePort::recvAtomicSnoop(PacketPtr pkt)
2592{
2593 // Snoops shouldn't happen when bypassing caches
2594 assert(!cache->system->bypassCaches());
2595
2596 return cache->recvAtomicSnoop(pkt);
2597}
2598
2599void
2600BaseCache::MemSidePort::recvFunctionalSnoop(PacketPtr pkt)
2601{
2602 // Snoops shouldn't happen when bypassing caches
2603 assert(!cache->system->bypassCaches());
2604
2605 // functional snoop (note that in contrast to atomic we don't have
2606 // a specific functionalSnoop method, as they have the same
2607 // behaviour regardless)
2608 cache->functionalAccess(pkt, false);
2609}
2610
2611void
2612BaseCache::CacheReqPacketQueue::sendDeferredPacket()
2613{
2614 // sanity check
2615 assert(!waitingOnRetry);
2616
2617 // there should never be any deferred request packets in the
2618 // queue, instead we resly on the cache to provide the packets
2619 // from the MSHR queue or write queue
2620 assert(deferredPacketReadyTime() == MaxTick);
2621
2622 // check for request packets (requests & writebacks)
2623 QueueEntry* entry = cache.getNextQueueEntry();
2624
2625 if (!entry) {
2626 // can happen if e.g. we attempt a writeback and fail, but
2627 // before the retry, the writeback is eliminated because
2628 // we snoop another cache's ReadEx.
2629 } else {
2630 // let our snoop responses go first if there are responses to
2631 // the same addresses
2632 if (checkConflictingSnoop(entry->getTarget()->pkt)) {
2633 return;
2634 }
2635 waitingOnRetry = entry->sendPacket(cache);
2636 }
2637
2638 // if we succeeded and are not waiting for a retry, schedule the
2639 // next send considering when the next queue is ready, note that
2640 // snoop responses have their own packet queue and thus schedule
2641 // their own events
2642 if (!waitingOnRetry) {
2643 schedSendEvent(cache.nextQueueReadyTime());
2644 }
2645}
2646
2647BaseCache::MemSidePort::MemSidePort(const std::string &_name,
2648 BaseCache *_cache,
2649 const std::string &_label)
2650 : CacheMasterPort(_name, _cache, _reqQueue, _snoopRespQueue),
2651 _reqQueue(*_cache, *this, _snoopRespQueue, _label),
2652 _snoopRespQueue(*_cache, *this, true, _label), cache(_cache)
2653{
2654}
2655
2656void
2657WriteAllocator::updateMode(Addr write_addr, unsigned write_size,
2658 Addr blk_addr)
2659{
2660 // check if we are continuing where the last write ended
2661 if (nextAddr == write_addr) {
2662 delayCtr[blk_addr] = delayThreshold;
2663 // stop if we have already saturated
2664 if (mode != WriteMode::NO_ALLOCATE) {
2665 byteCount += write_size;
2666 // switch to streaming mode if we have passed the lower
2667 // threshold
2668 if (mode == WriteMode::ALLOCATE &&
2669 byteCount > coalesceLimit) {
2670 mode = WriteMode::COALESCE;
2671 DPRINTF(Cache, "Switched to write coalescing\n");
2672 } else if (mode == WriteMode::COALESCE &&
2673 byteCount > noAllocateLimit) {
2674 // and continue and switch to non-allocating mode if we
2675 // pass the upper threshold
2676 mode = WriteMode::NO_ALLOCATE;
2677 DPRINTF(Cache, "Switched to write-no-allocate\n");
2678 }
2679 }
2680 } else {
2681 // we did not see a write matching the previous one, start
2682 // over again
2683 byteCount = write_size;
2684 mode = WriteMode::ALLOCATE;
2685 resetDelay(blk_addr);
2686 }
2687 nextAddr = write_addr + write_size;
2688}
2689
2690WriteAllocator*
2691WriteAllocatorParams::create()
2692{
2693 return new WriteAllocator(this);
2694}