1/*
2 * Copyright (c) 2004-2006 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Kevin Lim
29 * Korey Sewell
30 */
31
32#include "config/full_system.hh"
33#include "config/use_checker.hh"
34
35#include <algorithm>
36#include <string>
37
38#include "arch/utility.hh"
39#include "base/loader/symtab.hh"
40#include "base/timebuf.hh"
41#include "cpu/exetrace.hh"
42#include "cpu/o3/commit.hh"
43#include "cpu/o3/thread_state.hh"
44
45#if USE_CHECKER
46#include "cpu/checker/cpu.hh"
47#endif
48
49template <class Impl>
50DefaultCommit<Impl>::TrapEvent::TrapEvent(DefaultCommit<Impl> *_commit,
51 unsigned _tid)
52 : Event(&mainEventQueue, CPU_Tick_Pri), commit(_commit), tid(_tid)
53{
54 this->setFlags(Event::AutoDelete);
55}
56
57template <class Impl>
58void
59DefaultCommit<Impl>::TrapEvent::process()
60{
61 // This will get reset by commit if it was switched out at the
62 // time of this event processing.
63 commit->trapSquash[tid] = true;
64}
65
66template <class Impl>
67const char *
68DefaultCommit<Impl>::TrapEvent::description()
69{
70 return "Trap event";
71}
72
73template <class Impl>
74DefaultCommit<Impl>::DefaultCommit(Params *params)
75 : squashCounter(0),
76 iewToCommitDelay(params->iewToCommitDelay),
77 commitToIEWDelay(params->commitToIEWDelay),
78 renameToROBDelay(params->renameToROBDelay),
79 fetchToCommitDelay(params->commitToFetchDelay),
80 renameWidth(params->renameWidth),
81 commitWidth(params->commitWidth),
82 numThreads(params->numberOfThreads),
83 drainPending(false),
84 switchedOut(false),
85 trapLatency(params->trapLatency)
86{
87 _status = Active;
88 _nextStatus = Inactive;
89 std::string policy = params->smtCommitPolicy;
90
91 //Convert string to lowercase
92 std::transform(policy.begin(), policy.end(), policy.begin(),
93 (int(*)(int)) tolower);
94
95 //Assign commit policy
96 if (policy == "aggressive"){
97 commitPolicy = Aggressive;
98
99 DPRINTF(Commit,"Commit Policy set to Aggressive.");
100 } else if (policy == "roundrobin"){
101 commitPolicy = RoundRobin;
102
103 //Set-Up Priority List
104 for (int tid=0; tid < numThreads; tid++) {
105 priority_list.push_back(tid);
106 }
107
108 DPRINTF(Commit,"Commit Policy set to Round Robin.");
109 } else if (policy == "oldestready"){
110 commitPolicy = OldestReady;
111
112 DPRINTF(Commit,"Commit Policy set to Oldest Ready.");
113 } else {
114 assert(0 && "Invalid SMT Commit Policy. Options Are: {Aggressive,"
115 "RoundRobin,OldestReady}");
116 }
117
118 for (int i=0; i < numThreads; i++) {
119 commitStatus[i] = Idle;
120 changedROBNumEntries[i] = false;
121 trapSquash[i] = false;
122 tcSquash[i] = false;
123 PC[i] = nextPC[i] = nextNPC[i] = 0;
124 }
125#if FULL_SYSTEM
126 interrupt = NoFault;
127#endif
128}
129
130template <class Impl>
131std::string
132DefaultCommit<Impl>::name() const
133{
134 return cpu->name() + ".commit";
135}
136
137template <class Impl>
138void
139DefaultCommit<Impl>::regStats()
140{
141 using namespace Stats;
142 commitCommittedInsts
143 .name(name() + ".commitCommittedInsts")
144 .desc("The number of committed instructions")
145 .prereq(commitCommittedInsts);
146 commitSquashedInsts
147 .name(name() + ".commitSquashedInsts")
148 .desc("The number of squashed insts skipped by commit")
149 .prereq(commitSquashedInsts);
150 commitSquashEvents
151 .name(name() + ".commitSquashEvents")
152 .desc("The number of times commit is told to squash")
153 .prereq(commitSquashEvents);
154 commitNonSpecStalls
155 .name(name() + ".commitNonSpecStalls")
156 .desc("The number of times commit has been forced to stall to "
157 "communicate backwards")
158 .prereq(commitNonSpecStalls);
159 branchMispredicts
160 .name(name() + ".branchMispredicts")
161 .desc("The number of times a branch was mispredicted")
162 .prereq(branchMispredicts);
163 numCommittedDist
164 .init(0,commitWidth,1)
165 .name(name() + ".COM:committed_per_cycle")
166 .desc("Number of insts commited each cycle")
167 .flags(Stats::pdf)
168 ;
169
170 statComInst
171 .init(cpu->number_of_threads)
172 .name(name() + ".COM:count")
173 .desc("Number of instructions committed")
174 .flags(total)
175 ;
176
177 statComSwp
178 .init(cpu->number_of_threads)
179 .name(name() + ".COM:swp_count")
180 .desc("Number of s/w prefetches committed")
181 .flags(total)
182 ;
183
184 statComRefs
185 .init(cpu->number_of_threads)
186 .name(name() + ".COM:refs")
187 .desc("Number of memory references committed")
188 .flags(total)
189 ;
190
191 statComLoads
192 .init(cpu->number_of_threads)
193 .name(name() + ".COM:loads")
194 .desc("Number of loads committed")
195 .flags(total)
196 ;
197
198 statComMembars
199 .init(cpu->number_of_threads)
200 .name(name() + ".COM:membars")
201 .desc("Number of memory barriers committed")
202 .flags(total)
203 ;
204
205 statComBranches
206 .init(cpu->number_of_threads)
207 .name(name() + ".COM:branches")
208 .desc("Number of branches committed")
209 .flags(total)
210 ;
211
212 commitEligible
213 .init(cpu->number_of_threads)
214 .name(name() + ".COM:bw_limited")
215 .desc("number of insts not committed due to BW limits")
216 .flags(total)
217 ;
218
219 commitEligibleSamples
220 .name(name() + ".COM:bw_lim_events")
221 .desc("number cycles where commit BW limit reached")
222 ;
223}
224
225template <class Impl>
226void
227DefaultCommit<Impl>::setCPU(O3CPU *cpu_ptr)
228{
229 DPRINTF(Commit, "Commit: Setting CPU pointer.\n");
230 cpu = cpu_ptr;
231
232 // Commit must broadcast the number of free entries it has at the start of
233 // the simulation, so it starts as active.
234 cpu->activateStage(O3CPU::CommitIdx);
235
236 trapLatency = cpu->cycles(trapLatency);
237}
238
239template <class Impl>
240void
241DefaultCommit<Impl>::setThreads(std::vector<Thread *> &threads)
242{
243 thread = threads;
244}
245
246template <class Impl>
247void
248DefaultCommit<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
249{
250 DPRINTF(Commit, "Commit: Setting time buffer pointer.\n");
251 timeBuffer = tb_ptr;
252
253 // Setup wire to send information back to IEW.
254 toIEW = timeBuffer->getWire(0);
255
256 // Setup wire to read data from IEW (for the ROB).
257 robInfoFromIEW = timeBuffer->getWire(-iewToCommitDelay);
258}
259
260template <class Impl>
261void
262DefaultCommit<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr)
263{
264 DPRINTF(Commit, "Commit: Setting fetch queue pointer.\n");
265 fetchQueue = fq_ptr;
266
267 // Setup wire to get instructions from rename (for the ROB).
268 fromFetch = fetchQueue->getWire(-fetchToCommitDelay);
269}
270
271template <class Impl>
272void
273DefaultCommit<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
274{
275 DPRINTF(Commit, "Commit: Setting rename queue pointer.\n");
276 renameQueue = rq_ptr;
277
278 // Setup wire to get instructions from rename (for the ROB).
279 fromRename = renameQueue->getWire(-renameToROBDelay);
280}
281
282template <class Impl>
283void
284DefaultCommit<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr)
285{
286 DPRINTF(Commit, "Commit: Setting IEW queue pointer.\n");
287 iewQueue = iq_ptr;
288
289 // Setup wire to get instructions from IEW.
290 fromIEW = iewQueue->getWire(-iewToCommitDelay);
291}
292
293template <class Impl>
294void
295DefaultCommit<Impl>::setIEWStage(IEW *iew_stage)
296{
297 iewStage = iew_stage;
298}
299
300template<class Impl>
301void
302DefaultCommit<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
303{
304 DPRINTF(Commit, "Commit: Setting active threads list pointer.\n");
305 activeThreads = at_ptr;
306}
307
308template <class Impl>
309void
310DefaultCommit<Impl>::setRenameMap(RenameMap rm_ptr[])
311{
312 DPRINTF(Commit, "Setting rename map pointers.\n");
313
314 for (int i=0; i < numThreads; i++) {
315 renameMap[i] = &rm_ptr[i];
316 }
317}
318
319template <class Impl>
320void
321DefaultCommit<Impl>::setROB(ROB *rob_ptr)
322{
323 DPRINTF(Commit, "Commit: Setting ROB pointer.\n");
324 rob = rob_ptr;
325}
326
327template <class Impl>
328void
329DefaultCommit<Impl>::initStage()
330{
331 rob->setActiveThreads(activeThreads);
332 rob->resetEntries();
333
334 // Broadcast the number of free entries.
335 for (int i=0; i < numThreads; i++) {
336 toIEW->commitInfo[i].usedROB = true;
337 toIEW->commitInfo[i].freeROBEntries = rob->numFreeEntries(i);
338 }
339
340 cpu->activityThisCycle();
341}
342
343template <class Impl>
344bool
345DefaultCommit<Impl>::drain()
346{
347 drainPending = true;
348
349 return false;
350}
351
352template <class Impl>
353void
354DefaultCommit<Impl>::switchOut()
355{
356 switchedOut = true;
357 drainPending = false;
358 rob->switchOut();
359}
360
361template <class Impl>
362void
363DefaultCommit<Impl>::resume()
364{
365 drainPending = false;
366}
367
368template <class Impl>
369void
370DefaultCommit<Impl>::takeOverFrom()
371{
372 switchedOut = false;
373 _status = Active;
374 _nextStatus = Inactive;
375 for (int i=0; i < numThreads; i++) {
376 commitStatus[i] = Idle;
377 changedROBNumEntries[i] = false;
378 trapSquash[i] = false;
379 tcSquash[i] = false;
380 }
381 squashCounter = 0;
382 rob->takeOverFrom();
383}
384
385template <class Impl>
386void
387DefaultCommit<Impl>::updateStatus()
388{
389 // reset ROB changed variable
390 std::list<unsigned>::iterator threads = activeThreads->begin();
391 std::list<unsigned>::iterator end = activeThreads->end();
392
393 while (threads != end) {
394 unsigned tid = *threads++;
395
396 changedROBNumEntries[tid] = false;
397
398 // Also check if any of the threads has a trap pending
399 if (commitStatus[tid] == TrapPending ||
400 commitStatus[tid] == FetchTrapPending) {
401 _nextStatus = Active;
402 }
403 }
404
405 if (_nextStatus == Inactive && _status == Active) {
406 DPRINTF(Activity, "Deactivating stage.\n");
407 cpu->deactivateStage(O3CPU::CommitIdx);
408 } else if (_nextStatus == Active && _status == Inactive) {
409 DPRINTF(Activity, "Activating stage.\n");
410 cpu->activateStage(O3CPU::CommitIdx);
411 }
412
413 _status = _nextStatus;
414}
415
416template <class Impl>
417void
418DefaultCommit<Impl>::setNextStatus()
419{
420 int squashes = 0;
421
422 std::list<unsigned>::iterator threads = activeThreads->begin();
423 std::list<unsigned>::iterator end = activeThreads->end();
424
425 while (threads != end) {
426 unsigned tid = *threads++;
427
428 if (commitStatus[tid] == ROBSquashing) {
429 squashes++;
430 }
431 }
432
433 squashCounter = squashes;
434
435 // If commit is currently squashing, then it will have activity for the
436 // next cycle. Set its next status as active.
437 if (squashCounter) {
438 _nextStatus = Active;
439 }
440}
441
442template <class Impl>
443bool
444DefaultCommit<Impl>::changedROBEntries()
445{
446 std::list<unsigned>::iterator threads = activeThreads->begin();
447 std::list<unsigned>::iterator end = activeThreads->end();
448
449 while (threads != end) {
450 unsigned tid = *threads++;
451
452 if (changedROBNumEntries[tid]) {
453 return true;
454 }
455 }
456
457 return false;
458}
459
460template <class Impl>
461unsigned
462DefaultCommit<Impl>::numROBFreeEntries(unsigned tid)
463{
464 return rob->numFreeEntries(tid);
465}
466
467template <class Impl>
468void
469DefaultCommit<Impl>::generateTrapEvent(unsigned tid)
470{
471 DPRINTF(Commit, "Generating trap event for [tid:%i]\n", tid);
472
473 TrapEvent *trap = new TrapEvent(this, tid);
474
475 trap->schedule(curTick + trapLatency);
476
477 thread[tid]->trapPending = true;
478}
479
480template <class Impl>
481void
482DefaultCommit<Impl>::generateTCEvent(unsigned tid)
483{
484 DPRINTF(Commit, "Generating TC squash event for [tid:%i]\n", tid);
485
486 tcSquash[tid] = true;
487}
488
489template <class Impl>
490void
491DefaultCommit<Impl>::squashAll(unsigned tid)
492{
493 // If we want to include the squashing instruction in the squash,
494 // then use one older sequence number.
495 // Hopefully this doesn't mess things up. Basically I want to squash
496 // all instructions of this thread.
497 InstSeqNum squashed_inst = rob->isEmpty() ?
498 0 : rob->readHeadInst(tid)->seqNum - 1;;
499
500 // All younger instructions will be squashed. Set the sequence
501 // number as the youngest instruction in the ROB (0 in this case.
502 // Hopefully nothing breaks.)
503 youngestSeqNum[tid] = 0;
504
505 rob->squash(squashed_inst, tid);
506 changedROBNumEntries[tid] = true;
507
508 // Send back the sequence number of the squashed instruction.
509 toIEW->commitInfo[tid].doneSeqNum = squashed_inst;
510
511 // Send back the squash signal to tell stages that they should
512 // squash.
513 toIEW->commitInfo[tid].squash = true;
514
515 // Send back the rob squashing signal so other stages know that
516 // the ROB is in the process of squashing.
517 toIEW->commitInfo[tid].robSquashing = true;
518
519 toIEW->commitInfo[tid].branchMispredict = false;
520
521 toIEW->commitInfo[tid].nextPC = PC[tid];
522}
523
524template <class Impl>
525void
526DefaultCommit<Impl>::squashFromTrap(unsigned tid)
527{
528 squashAll(tid);
529
530 DPRINTF(Commit, "Squashing from trap, restarting at PC %#x\n", PC[tid]);
531
532 thread[tid]->trapPending = false;
533 thread[tid]->inSyscall = false;
534
535 trapSquash[tid] = false;
536
537 commitStatus[tid] = ROBSquashing;
538 cpu->activityThisCycle();
539}
540
541template <class Impl>
542void
543DefaultCommit<Impl>::squashFromTC(unsigned tid)
544{
545 squashAll(tid);
546
547 DPRINTF(Commit, "Squashing from TC, restarting at PC %#x\n", PC[tid]);
548
549 thread[tid]->inSyscall = false;
550 assert(!thread[tid]->trapPending);
551
552 commitStatus[tid] = ROBSquashing;
553 cpu->activityThisCycle();
554
555 tcSquash[tid] = false;
556}
557
558template <class Impl>
559void
560DefaultCommit<Impl>::tick()
561{
562 wroteToTimeBuffer = false;
563 _nextStatus = Inactive;
564
565 if (drainPending && rob->isEmpty() && !iewStage->hasStoresToWB()) {
566 cpu->signalDrained();
567 drainPending = false;
568 return;
569 }
570
571 if (activeThreads->empty())
572 return;
573
574 std::list<unsigned>::iterator threads = activeThreads->begin();
575 std::list<unsigned>::iterator end = activeThreads->end();
576
577 // Check if any of the threads are done squashing. Change the
578 // status if they are done.
579 while (threads != end) {
580 unsigned tid = *threads++;
581
582 if (commitStatus[tid] == ROBSquashing) {
583
584 if (rob->isDoneSquashing(tid)) {
585 commitStatus[tid] = Running;
586 } else {
587 DPRINTF(Commit,"[tid:%u]: Still Squashing, cannot commit any"
588 " insts this cycle.\n", tid);
589 rob->doSquash(tid);
590 toIEW->commitInfo[tid].robSquashing = true;
591 wroteToTimeBuffer = true;
592 }
593 }
594 }
595
596 commit();
597
598 markCompletedInsts();
599
600 threads = activeThreads->begin();
601
602 while (threads != end) {
603 unsigned tid = *threads++;
604
605 if (!rob->isEmpty(tid) && rob->readHeadInst(tid)->readyToCommit()) {
606 // The ROB has more instructions it can commit. Its next status
607 // will be active.
608 _nextStatus = Active;
609
610 DynInstPtr inst = rob->readHeadInst(tid);
611
612 DPRINTF(Commit,"[tid:%i]: Instruction [sn:%lli] PC %#x is head of"
613 " ROB and ready to commit\n",
614 tid, inst->seqNum, inst->readPC());
615
616 } else if (!rob->isEmpty(tid)) {
617 DynInstPtr inst = rob->readHeadInst(tid);
618
619 DPRINTF(Commit,"[tid:%i]: Can't commit, Instruction [sn:%lli] PC "
620 "%#x is head of ROB and not ready\n",
621 tid, inst->seqNum, inst->readPC());
622 }
623
624 DPRINTF(Commit, "[tid:%i]: ROB has %d insts & %d free entries.\n",
625 tid, rob->countInsts(tid), rob->numFreeEntries(tid));
626 }
627
628
629 if (wroteToTimeBuffer) {
630 DPRINTF(Activity, "Activity This Cycle.\n");
631 cpu->activityThisCycle();
632 }
633
634 updateStatus();
635}
636
637template <class Impl>
638void
639DefaultCommit<Impl>::commit()
640{
641
642 //////////////////////////////////////
643 // Check for interrupts
644 //////////////////////////////////////
645
646#if FULL_SYSTEM
647 if (interrupt != NoFault) {
648 // Wait until the ROB is empty and all stores have drained in
649 // order to enter the interrupt.
650 if (rob->isEmpty() && !iewStage->hasStoresToWB()) {
651 // Squash or record that I need to squash this cycle if
652 // an interrupt needed to be handled.
653 DPRINTF(Commit, "Interrupt detected.\n");
654
655 assert(!thread[0]->inSyscall);
656 thread[0]->inSyscall = true;
657
658 // CPU will handle interrupt.
659 cpu->processInterrupts(interrupt);
660
661 thread[0]->inSyscall = false;
662
663 commitStatus[0] = TrapPending;
664
665 // Generate trap squash event.
666 generateTrapEvent(0);
667
668 // Clear the interrupt now that it's been handled
669 toIEW->commitInfo[0].clearInterrupt = true;
670 interrupt = NoFault;
671 } else {
672 DPRINTF(Commit, "Interrupt pending, waiting for ROB to empty.\n");
673 }
674 } else if (cpu->checkInterrupts &&
675 cpu->check_interrupts(cpu->tcBase(0)) &&
676 commitStatus[0] != TrapPending &&
677 !trapSquash[0] &&
678 !tcSquash[0]) {
679 // Process interrupts if interrupts are enabled, not in PAL
680 // mode, and no other traps or external squashes are currently
681 // pending.
682 // @todo: Allow other threads to handle interrupts.
683
684 // Get any interrupt that happened
685 interrupt = cpu->getInterrupts();
686
687 if (interrupt != NoFault) {
688 // Tell fetch that there is an interrupt pending. This
689 // will make fetch wait until it sees a non PAL-mode PC,
690 // at which point it stops fetching instructions.
691 toIEW->commitInfo[0].interruptPending = true;
692 }
693 }
694
695#endif // FULL_SYSTEM
696
697 ////////////////////////////////////
698 // Check for any possible squashes, handle them first
699 ////////////////////////////////////
700 std::list<unsigned>::iterator threads = activeThreads->begin();
701 std::list<unsigned>::iterator end = activeThreads->end();
702
703 while (threads != end) {
704 unsigned tid = *threads++;
705
706 // Not sure which one takes priority. I think if we have
707 // both, that's a bad sign.
708 if (trapSquash[tid] == true) {
709 assert(!tcSquash[tid]);
710 squashFromTrap(tid);
711 } else if (tcSquash[tid] == true) {
712 squashFromTC(tid);
713 }
714
715 // Squashed sequence number must be older than youngest valid
716 // instruction in the ROB. This prevents squashes from younger
717 // instructions overriding squashes from older instructions.
718 if (fromIEW->squash[tid] &&
719 commitStatus[tid] != TrapPending &&
720 fromIEW->squashedSeqNum[tid] <= youngestSeqNum[tid]) {
721
722 DPRINTF(Commit, "[tid:%i]: Squashing due to PC %#x [sn:%i]\n",
723 tid,
724 fromIEW->mispredPC[tid],
725 fromIEW->squashedSeqNum[tid]);
726
727 DPRINTF(Commit, "[tid:%i]: Redirecting to PC %#x\n",
728 tid,
729 fromIEW->nextPC[tid]);
730
731 commitStatus[tid] = ROBSquashing;
732
733 // If we want to include the squashing instruction in the squash,
734 // then use one older sequence number.
735 InstSeqNum squashed_inst = fromIEW->squashedSeqNum[tid];
736
737#if ISA_HAS_DELAY_SLOT
738 InstSeqNum bdelay_done_seq_num;
739 bool squash_bdelay_slot;
740
741 if (fromIEW->branchMispredict[tid]) {
742 if (fromIEW->branchTaken[tid] &&
743 fromIEW->condDelaySlotBranch[tid]) {
744 DPRINTF(Commit, "[tid:%i]: Cond. delay slot branch"
745 "mispredicted as taken. Squashing after previous "
746 "inst, [sn:%i]\n",
747 tid, squashed_inst);
748 bdelay_done_seq_num = squashed_inst;
749 squash_bdelay_slot = true;
750 } else {
751 DPRINTF(Commit, "[tid:%i]: Branch Mispredict. Squashing "
752 "after delay slot [sn:%i]\n", tid, squashed_inst+1);
753 bdelay_done_seq_num = squashed_inst + 1;
754 squash_bdelay_slot = false;
755 }
756 } else {
757 bdelay_done_seq_num = squashed_inst;
758 squash_bdelay_slot = true;
759 }
760#endif
761
762 if (fromIEW->includeSquashInst[tid] == true) {
763 squashed_inst--;
764#if ISA_HAS_DELAY_SLOT
765 bdelay_done_seq_num--;
766#endif
767 }
768 // All younger instructions will be squashed. Set the sequence
769 // number as the youngest instruction in the ROB.
770 youngestSeqNum[tid] = squashed_inst;
771
772#if ISA_HAS_DELAY_SLOT
773 rob->squash(bdelay_done_seq_num, tid);
774 toIEW->commitInfo[tid].squashDelaySlot = squash_bdelay_slot;
775 toIEW->commitInfo[tid].bdelayDoneSeqNum = bdelay_done_seq_num;
776#else
777 rob->squash(squashed_inst, tid);
778 toIEW->commitInfo[tid].squashDelaySlot = true;
779#endif
780 changedROBNumEntries[tid] = true;
781
782 toIEW->commitInfo[tid].doneSeqNum = squashed_inst;
783
784 toIEW->commitInfo[tid].squash = true;
785
786 // Send back the rob squashing signal so other stages know that
787 // the ROB is in the process of squashing.
788 toIEW->commitInfo[tid].robSquashing = true;
789
790 toIEW->commitInfo[tid].branchMispredict =
791 fromIEW->branchMispredict[tid];
792
793 toIEW->commitInfo[tid].branchTaken =
794 fromIEW->branchTaken[tid];
795
796 toIEW->commitInfo[tid].nextPC = fromIEW->nextPC[tid];
797
798 toIEW->commitInfo[tid].mispredPC = fromIEW->mispredPC[tid];
799
800 if (toIEW->commitInfo[tid].branchMispredict) {
801 ++branchMispredicts;
802 }
803 }
804
805 }
806
807 setNextStatus();
808
809 if (squashCounter != numThreads) {
810 // If we're not currently squashing, then get instructions.
811 getInsts();
812
813 // Try to commit any instructions.
814 commitInsts();
815 } else {
816#if ISA_HAS_DELAY_SLOT
817 skidInsert();
818#endif
819 }
820
821 //Check for any activity
822 threads = activeThreads->begin();
823
824 while (threads != end) {
825 unsigned tid = *threads++;
826
827 if (changedROBNumEntries[tid]) {
828 toIEW->commitInfo[tid].usedROB = true;
829 toIEW->commitInfo[tid].freeROBEntries = rob->numFreeEntries(tid);
830
831 if (rob->isEmpty(tid)) {
832 toIEW->commitInfo[tid].emptyROB = true;
833 }
834
835 wroteToTimeBuffer = true;
836 changedROBNumEntries[tid] = false;
837 }
838 }
839}
840
841template <class Impl>
842void
843DefaultCommit<Impl>::commitInsts()
844{
845 ////////////////////////////////////
846 // Handle commit
847 // Note that commit will be handled prior to putting new
848 // instructions in the ROB so that the ROB only tries to commit
849 // instructions it has in this current cycle, and not instructions
850 // it is writing in during this cycle. Can't commit and squash
851 // things at the same time...
852 ////////////////////////////////////
853
854 DPRINTF(Commit, "Trying to commit instructions in the ROB.\n");
855
856 unsigned num_committed = 0;
857
858 DynInstPtr head_inst;
859
860 // Commit as many instructions as possible until the commit bandwidth
861 // limit is reached, or it becomes impossible to commit any more.
862 while (num_committed < commitWidth) {
863 int commit_thread = getCommittingThread();
864
865 if (commit_thread == -1 || !rob->isHeadReady(commit_thread))
866 break;
867
868 head_inst = rob->readHeadInst(commit_thread);
869
870 int tid = head_inst->threadNumber;
871
872 assert(tid == commit_thread);
873
874 DPRINTF(Commit, "Trying to commit head instruction, [sn:%i] [tid:%i]\n",
875 head_inst->seqNum, tid);
876
877 // If the head instruction is squashed, it is ready to retire
878 // (be removed from the ROB) at any time.
879 if (head_inst->isSquashed()) {
880
881 DPRINTF(Commit, "Retiring squashed instruction from "
882 "ROB.\n");
883
884 rob->retireHead(commit_thread);
885
886 ++commitSquashedInsts;
887
888 // Record that the number of ROB entries has changed.
889 changedROBNumEntries[tid] = true;
890 } else {
891 PC[tid] = head_inst->readPC();
892 nextPC[tid] = head_inst->readNextPC();
893 nextNPC[tid] = head_inst->readNextNPC();
894
895 // Increment the total number of non-speculative instructions
896 // executed.
897 // Hack for now: it really shouldn't happen until after the
898 // commit is deemed to be successful, but this count is needed
899 // for syscalls.
900 thread[tid]->funcExeInst++;
901
902 // Try to commit the head instruction.
903 bool commit_success = commitHead(head_inst, num_committed);
904
905 if (commit_success) {
906 ++num_committed;
907
908 changedROBNumEntries[tid] = true;
909
910 // Set the doneSeqNum to the youngest committed instruction.
911 toIEW->commitInfo[tid].doneSeqNum = head_inst->seqNum;
912
913 ++commitCommittedInsts;
914
915 // To match the old model, don't count nops and instruction
916 // prefetches towards the total commit count.
917 if (!head_inst->isNop() && !head_inst->isInstPrefetch()) {
918 cpu->instDone(tid);
919 }
920
921 PC[tid] = nextPC[tid];
922#if ISA_HAS_DELAY_SLOT
923 nextPC[tid] = nextNPC[tid];
924 nextNPC[tid] = nextNPC[tid] + sizeof(TheISA::MachInst);
925#else
926 nextPC[tid] = nextPC[tid] + sizeof(TheISA::MachInst);
927#endif
928
929#if FULL_SYSTEM
930 int count = 0;
931 Addr oldpc;
932 do {
933 // Debug statement. Checks to make sure we're not
934 // currently updating state while handling PC events.
935 if (count == 0)
936 assert(!thread[tid]->inSyscall &&
937 !thread[tid]->trapPending);
938 oldpc = PC[tid];
939 cpu->system->pcEventQueue.service(
940 thread[tid]->getTC());
941 count++;
942 } while (oldpc != PC[tid]);
943 if (count > 1) {
944 DPRINTF(Commit, "PC skip function event, stopping commit\n");
945 break;
946 }
947#endif
948 } else {
949 DPRINTF(Commit, "Unable to commit head instruction PC:%#x "
950 "[tid:%i] [sn:%i].\n",
951 head_inst->readPC(), tid ,head_inst->seqNum);
952 break;
953 }
954 }
955 }
956
957 DPRINTF(CommitRate, "%i\n", num_committed);
958 numCommittedDist.sample(num_committed);
959
960 if (num_committed == commitWidth) {
961 commitEligibleSamples++;
962 }
963}
964
965template <class Impl>
966bool
967DefaultCommit<Impl>::commitHead(DynInstPtr &head_inst, unsigned inst_num)
968{
969 assert(head_inst);
970
971 int tid = head_inst->threadNumber;
972
973 // If the instruction is not executed yet, then it will need extra
974 // handling. Signal backwards that it should be executed.
975 if (!head_inst->isExecuted()) {
976 // Keep this number correct. We have not yet actually executed
977 // and committed this instruction.
978 thread[tid]->funcExeInst--;
979
980 head_inst->setAtCommit();
981
982 if (head_inst->isNonSpeculative() ||
983 head_inst->isStoreConditional() ||
984 head_inst->isMemBarrier() ||
985 head_inst->isWriteBarrier()) {
986
987 DPRINTF(Commit, "Encountered a barrier or non-speculative "
988 "instruction [sn:%lli] at the head of the ROB, PC %#x.\n",
989 head_inst->seqNum, head_inst->readPC());
990
| 1/*
2 * Copyright (c) 2004-2006 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Kevin Lim
29 * Korey Sewell
30 */
31
32#include "config/full_system.hh"
33#include "config/use_checker.hh"
34
35#include <algorithm>
36#include <string>
37
38#include "arch/utility.hh"
39#include "base/loader/symtab.hh"
40#include "base/timebuf.hh"
41#include "cpu/exetrace.hh"
42#include "cpu/o3/commit.hh"
43#include "cpu/o3/thread_state.hh"
44
45#if USE_CHECKER
46#include "cpu/checker/cpu.hh"
47#endif
48
49template <class Impl>
50DefaultCommit<Impl>::TrapEvent::TrapEvent(DefaultCommit<Impl> *_commit,
51 unsigned _tid)
52 : Event(&mainEventQueue, CPU_Tick_Pri), commit(_commit), tid(_tid)
53{
54 this->setFlags(Event::AutoDelete);
55}
56
57template <class Impl>
58void
59DefaultCommit<Impl>::TrapEvent::process()
60{
61 // This will get reset by commit if it was switched out at the
62 // time of this event processing.
63 commit->trapSquash[tid] = true;
64}
65
66template <class Impl>
67const char *
68DefaultCommit<Impl>::TrapEvent::description()
69{
70 return "Trap event";
71}
72
73template <class Impl>
74DefaultCommit<Impl>::DefaultCommit(Params *params)
75 : squashCounter(0),
76 iewToCommitDelay(params->iewToCommitDelay),
77 commitToIEWDelay(params->commitToIEWDelay),
78 renameToROBDelay(params->renameToROBDelay),
79 fetchToCommitDelay(params->commitToFetchDelay),
80 renameWidth(params->renameWidth),
81 commitWidth(params->commitWidth),
82 numThreads(params->numberOfThreads),
83 drainPending(false),
84 switchedOut(false),
85 trapLatency(params->trapLatency)
86{
87 _status = Active;
88 _nextStatus = Inactive;
89 std::string policy = params->smtCommitPolicy;
90
91 //Convert string to lowercase
92 std::transform(policy.begin(), policy.end(), policy.begin(),
93 (int(*)(int)) tolower);
94
95 //Assign commit policy
96 if (policy == "aggressive"){
97 commitPolicy = Aggressive;
98
99 DPRINTF(Commit,"Commit Policy set to Aggressive.");
100 } else if (policy == "roundrobin"){
101 commitPolicy = RoundRobin;
102
103 //Set-Up Priority List
104 for (int tid=0; tid < numThreads; tid++) {
105 priority_list.push_back(tid);
106 }
107
108 DPRINTF(Commit,"Commit Policy set to Round Robin.");
109 } else if (policy == "oldestready"){
110 commitPolicy = OldestReady;
111
112 DPRINTF(Commit,"Commit Policy set to Oldest Ready.");
113 } else {
114 assert(0 && "Invalid SMT Commit Policy. Options Are: {Aggressive,"
115 "RoundRobin,OldestReady}");
116 }
117
118 for (int i=0; i < numThreads; i++) {
119 commitStatus[i] = Idle;
120 changedROBNumEntries[i] = false;
121 trapSquash[i] = false;
122 tcSquash[i] = false;
123 PC[i] = nextPC[i] = nextNPC[i] = 0;
124 }
125#if FULL_SYSTEM
126 interrupt = NoFault;
127#endif
128}
129
130template <class Impl>
131std::string
132DefaultCommit<Impl>::name() const
133{
134 return cpu->name() + ".commit";
135}
136
137template <class Impl>
138void
139DefaultCommit<Impl>::regStats()
140{
141 using namespace Stats;
142 commitCommittedInsts
143 .name(name() + ".commitCommittedInsts")
144 .desc("The number of committed instructions")
145 .prereq(commitCommittedInsts);
146 commitSquashedInsts
147 .name(name() + ".commitSquashedInsts")
148 .desc("The number of squashed insts skipped by commit")
149 .prereq(commitSquashedInsts);
150 commitSquashEvents
151 .name(name() + ".commitSquashEvents")
152 .desc("The number of times commit is told to squash")
153 .prereq(commitSquashEvents);
154 commitNonSpecStalls
155 .name(name() + ".commitNonSpecStalls")
156 .desc("The number of times commit has been forced to stall to "
157 "communicate backwards")
158 .prereq(commitNonSpecStalls);
159 branchMispredicts
160 .name(name() + ".branchMispredicts")
161 .desc("The number of times a branch was mispredicted")
162 .prereq(branchMispredicts);
163 numCommittedDist
164 .init(0,commitWidth,1)
165 .name(name() + ".COM:committed_per_cycle")
166 .desc("Number of insts commited each cycle")
167 .flags(Stats::pdf)
168 ;
169
170 statComInst
171 .init(cpu->number_of_threads)
172 .name(name() + ".COM:count")
173 .desc("Number of instructions committed")
174 .flags(total)
175 ;
176
177 statComSwp
178 .init(cpu->number_of_threads)
179 .name(name() + ".COM:swp_count")
180 .desc("Number of s/w prefetches committed")
181 .flags(total)
182 ;
183
184 statComRefs
185 .init(cpu->number_of_threads)
186 .name(name() + ".COM:refs")
187 .desc("Number of memory references committed")
188 .flags(total)
189 ;
190
191 statComLoads
192 .init(cpu->number_of_threads)
193 .name(name() + ".COM:loads")
194 .desc("Number of loads committed")
195 .flags(total)
196 ;
197
198 statComMembars
199 .init(cpu->number_of_threads)
200 .name(name() + ".COM:membars")
201 .desc("Number of memory barriers committed")
202 .flags(total)
203 ;
204
205 statComBranches
206 .init(cpu->number_of_threads)
207 .name(name() + ".COM:branches")
208 .desc("Number of branches committed")
209 .flags(total)
210 ;
211
212 commitEligible
213 .init(cpu->number_of_threads)
214 .name(name() + ".COM:bw_limited")
215 .desc("number of insts not committed due to BW limits")
216 .flags(total)
217 ;
218
219 commitEligibleSamples
220 .name(name() + ".COM:bw_lim_events")
221 .desc("number cycles where commit BW limit reached")
222 ;
223}
224
225template <class Impl>
226void
227DefaultCommit<Impl>::setCPU(O3CPU *cpu_ptr)
228{
229 DPRINTF(Commit, "Commit: Setting CPU pointer.\n");
230 cpu = cpu_ptr;
231
232 // Commit must broadcast the number of free entries it has at the start of
233 // the simulation, so it starts as active.
234 cpu->activateStage(O3CPU::CommitIdx);
235
236 trapLatency = cpu->cycles(trapLatency);
237}
238
239template <class Impl>
240void
241DefaultCommit<Impl>::setThreads(std::vector<Thread *> &threads)
242{
243 thread = threads;
244}
245
246template <class Impl>
247void
248DefaultCommit<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
249{
250 DPRINTF(Commit, "Commit: Setting time buffer pointer.\n");
251 timeBuffer = tb_ptr;
252
253 // Setup wire to send information back to IEW.
254 toIEW = timeBuffer->getWire(0);
255
256 // Setup wire to read data from IEW (for the ROB).
257 robInfoFromIEW = timeBuffer->getWire(-iewToCommitDelay);
258}
259
260template <class Impl>
261void
262DefaultCommit<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr)
263{
264 DPRINTF(Commit, "Commit: Setting fetch queue pointer.\n");
265 fetchQueue = fq_ptr;
266
267 // Setup wire to get instructions from rename (for the ROB).
268 fromFetch = fetchQueue->getWire(-fetchToCommitDelay);
269}
270
271template <class Impl>
272void
273DefaultCommit<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
274{
275 DPRINTF(Commit, "Commit: Setting rename queue pointer.\n");
276 renameQueue = rq_ptr;
277
278 // Setup wire to get instructions from rename (for the ROB).
279 fromRename = renameQueue->getWire(-renameToROBDelay);
280}
281
282template <class Impl>
283void
284DefaultCommit<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr)
285{
286 DPRINTF(Commit, "Commit: Setting IEW queue pointer.\n");
287 iewQueue = iq_ptr;
288
289 // Setup wire to get instructions from IEW.
290 fromIEW = iewQueue->getWire(-iewToCommitDelay);
291}
292
293template <class Impl>
294void
295DefaultCommit<Impl>::setIEWStage(IEW *iew_stage)
296{
297 iewStage = iew_stage;
298}
299
300template<class Impl>
301void
302DefaultCommit<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
303{
304 DPRINTF(Commit, "Commit: Setting active threads list pointer.\n");
305 activeThreads = at_ptr;
306}
307
308template <class Impl>
309void
310DefaultCommit<Impl>::setRenameMap(RenameMap rm_ptr[])
311{
312 DPRINTF(Commit, "Setting rename map pointers.\n");
313
314 for (int i=0; i < numThreads; i++) {
315 renameMap[i] = &rm_ptr[i];
316 }
317}
318
319template <class Impl>
320void
321DefaultCommit<Impl>::setROB(ROB *rob_ptr)
322{
323 DPRINTF(Commit, "Commit: Setting ROB pointer.\n");
324 rob = rob_ptr;
325}
326
327template <class Impl>
328void
329DefaultCommit<Impl>::initStage()
330{
331 rob->setActiveThreads(activeThreads);
332 rob->resetEntries();
333
334 // Broadcast the number of free entries.
335 for (int i=0; i < numThreads; i++) {
336 toIEW->commitInfo[i].usedROB = true;
337 toIEW->commitInfo[i].freeROBEntries = rob->numFreeEntries(i);
338 }
339
340 cpu->activityThisCycle();
341}
342
343template <class Impl>
344bool
345DefaultCommit<Impl>::drain()
346{
347 drainPending = true;
348
349 return false;
350}
351
352template <class Impl>
353void
354DefaultCommit<Impl>::switchOut()
355{
356 switchedOut = true;
357 drainPending = false;
358 rob->switchOut();
359}
360
361template <class Impl>
362void
363DefaultCommit<Impl>::resume()
364{
365 drainPending = false;
366}
367
368template <class Impl>
369void
370DefaultCommit<Impl>::takeOverFrom()
371{
372 switchedOut = false;
373 _status = Active;
374 _nextStatus = Inactive;
375 for (int i=0; i < numThreads; i++) {
376 commitStatus[i] = Idle;
377 changedROBNumEntries[i] = false;
378 trapSquash[i] = false;
379 tcSquash[i] = false;
380 }
381 squashCounter = 0;
382 rob->takeOverFrom();
383}
384
385template <class Impl>
386void
387DefaultCommit<Impl>::updateStatus()
388{
389 // reset ROB changed variable
390 std::list<unsigned>::iterator threads = activeThreads->begin();
391 std::list<unsigned>::iterator end = activeThreads->end();
392
393 while (threads != end) {
394 unsigned tid = *threads++;
395
396 changedROBNumEntries[tid] = false;
397
398 // Also check if any of the threads has a trap pending
399 if (commitStatus[tid] == TrapPending ||
400 commitStatus[tid] == FetchTrapPending) {
401 _nextStatus = Active;
402 }
403 }
404
405 if (_nextStatus == Inactive && _status == Active) {
406 DPRINTF(Activity, "Deactivating stage.\n");
407 cpu->deactivateStage(O3CPU::CommitIdx);
408 } else if (_nextStatus == Active && _status == Inactive) {
409 DPRINTF(Activity, "Activating stage.\n");
410 cpu->activateStage(O3CPU::CommitIdx);
411 }
412
413 _status = _nextStatus;
414}
415
416template <class Impl>
417void
418DefaultCommit<Impl>::setNextStatus()
419{
420 int squashes = 0;
421
422 std::list<unsigned>::iterator threads = activeThreads->begin();
423 std::list<unsigned>::iterator end = activeThreads->end();
424
425 while (threads != end) {
426 unsigned tid = *threads++;
427
428 if (commitStatus[tid] == ROBSquashing) {
429 squashes++;
430 }
431 }
432
433 squashCounter = squashes;
434
435 // If commit is currently squashing, then it will have activity for the
436 // next cycle. Set its next status as active.
437 if (squashCounter) {
438 _nextStatus = Active;
439 }
440}
441
442template <class Impl>
443bool
444DefaultCommit<Impl>::changedROBEntries()
445{
446 std::list<unsigned>::iterator threads = activeThreads->begin();
447 std::list<unsigned>::iterator end = activeThreads->end();
448
449 while (threads != end) {
450 unsigned tid = *threads++;
451
452 if (changedROBNumEntries[tid]) {
453 return true;
454 }
455 }
456
457 return false;
458}
459
460template <class Impl>
461unsigned
462DefaultCommit<Impl>::numROBFreeEntries(unsigned tid)
463{
464 return rob->numFreeEntries(tid);
465}
466
467template <class Impl>
468void
469DefaultCommit<Impl>::generateTrapEvent(unsigned tid)
470{
471 DPRINTF(Commit, "Generating trap event for [tid:%i]\n", tid);
472
473 TrapEvent *trap = new TrapEvent(this, tid);
474
475 trap->schedule(curTick + trapLatency);
476
477 thread[tid]->trapPending = true;
478}
479
480template <class Impl>
481void
482DefaultCommit<Impl>::generateTCEvent(unsigned tid)
483{
484 DPRINTF(Commit, "Generating TC squash event for [tid:%i]\n", tid);
485
486 tcSquash[tid] = true;
487}
488
489template <class Impl>
490void
491DefaultCommit<Impl>::squashAll(unsigned tid)
492{
493 // If we want to include the squashing instruction in the squash,
494 // then use one older sequence number.
495 // Hopefully this doesn't mess things up. Basically I want to squash
496 // all instructions of this thread.
497 InstSeqNum squashed_inst = rob->isEmpty() ?
498 0 : rob->readHeadInst(tid)->seqNum - 1;;
499
500 // All younger instructions will be squashed. Set the sequence
501 // number as the youngest instruction in the ROB (0 in this case.
502 // Hopefully nothing breaks.)
503 youngestSeqNum[tid] = 0;
504
505 rob->squash(squashed_inst, tid);
506 changedROBNumEntries[tid] = true;
507
508 // Send back the sequence number of the squashed instruction.
509 toIEW->commitInfo[tid].doneSeqNum = squashed_inst;
510
511 // Send back the squash signal to tell stages that they should
512 // squash.
513 toIEW->commitInfo[tid].squash = true;
514
515 // Send back the rob squashing signal so other stages know that
516 // the ROB is in the process of squashing.
517 toIEW->commitInfo[tid].robSquashing = true;
518
519 toIEW->commitInfo[tid].branchMispredict = false;
520
521 toIEW->commitInfo[tid].nextPC = PC[tid];
522}
523
524template <class Impl>
525void
526DefaultCommit<Impl>::squashFromTrap(unsigned tid)
527{
528 squashAll(tid);
529
530 DPRINTF(Commit, "Squashing from trap, restarting at PC %#x\n", PC[tid]);
531
532 thread[tid]->trapPending = false;
533 thread[tid]->inSyscall = false;
534
535 trapSquash[tid] = false;
536
537 commitStatus[tid] = ROBSquashing;
538 cpu->activityThisCycle();
539}
540
541template <class Impl>
542void
543DefaultCommit<Impl>::squashFromTC(unsigned tid)
544{
545 squashAll(tid);
546
547 DPRINTF(Commit, "Squashing from TC, restarting at PC %#x\n", PC[tid]);
548
549 thread[tid]->inSyscall = false;
550 assert(!thread[tid]->trapPending);
551
552 commitStatus[tid] = ROBSquashing;
553 cpu->activityThisCycle();
554
555 tcSquash[tid] = false;
556}
557
558template <class Impl>
559void
560DefaultCommit<Impl>::tick()
561{
562 wroteToTimeBuffer = false;
563 _nextStatus = Inactive;
564
565 if (drainPending && rob->isEmpty() && !iewStage->hasStoresToWB()) {
566 cpu->signalDrained();
567 drainPending = false;
568 return;
569 }
570
571 if (activeThreads->empty())
572 return;
573
574 std::list<unsigned>::iterator threads = activeThreads->begin();
575 std::list<unsigned>::iterator end = activeThreads->end();
576
577 // Check if any of the threads are done squashing. Change the
578 // status if they are done.
579 while (threads != end) {
580 unsigned tid = *threads++;
581
582 if (commitStatus[tid] == ROBSquashing) {
583
584 if (rob->isDoneSquashing(tid)) {
585 commitStatus[tid] = Running;
586 } else {
587 DPRINTF(Commit,"[tid:%u]: Still Squashing, cannot commit any"
588 " insts this cycle.\n", tid);
589 rob->doSquash(tid);
590 toIEW->commitInfo[tid].robSquashing = true;
591 wroteToTimeBuffer = true;
592 }
593 }
594 }
595
596 commit();
597
598 markCompletedInsts();
599
600 threads = activeThreads->begin();
601
602 while (threads != end) {
603 unsigned tid = *threads++;
604
605 if (!rob->isEmpty(tid) && rob->readHeadInst(tid)->readyToCommit()) {
606 // The ROB has more instructions it can commit. Its next status
607 // will be active.
608 _nextStatus = Active;
609
610 DynInstPtr inst = rob->readHeadInst(tid);
611
612 DPRINTF(Commit,"[tid:%i]: Instruction [sn:%lli] PC %#x is head of"
613 " ROB and ready to commit\n",
614 tid, inst->seqNum, inst->readPC());
615
616 } else if (!rob->isEmpty(tid)) {
617 DynInstPtr inst = rob->readHeadInst(tid);
618
619 DPRINTF(Commit,"[tid:%i]: Can't commit, Instruction [sn:%lli] PC "
620 "%#x is head of ROB and not ready\n",
621 tid, inst->seqNum, inst->readPC());
622 }
623
624 DPRINTF(Commit, "[tid:%i]: ROB has %d insts & %d free entries.\n",
625 tid, rob->countInsts(tid), rob->numFreeEntries(tid));
626 }
627
628
629 if (wroteToTimeBuffer) {
630 DPRINTF(Activity, "Activity This Cycle.\n");
631 cpu->activityThisCycle();
632 }
633
634 updateStatus();
635}
636
637template <class Impl>
638void
639DefaultCommit<Impl>::commit()
640{
641
642 //////////////////////////////////////
643 // Check for interrupts
644 //////////////////////////////////////
645
646#if FULL_SYSTEM
647 if (interrupt != NoFault) {
648 // Wait until the ROB is empty and all stores have drained in
649 // order to enter the interrupt.
650 if (rob->isEmpty() && !iewStage->hasStoresToWB()) {
651 // Squash or record that I need to squash this cycle if
652 // an interrupt needed to be handled.
653 DPRINTF(Commit, "Interrupt detected.\n");
654
655 assert(!thread[0]->inSyscall);
656 thread[0]->inSyscall = true;
657
658 // CPU will handle interrupt.
659 cpu->processInterrupts(interrupt);
660
661 thread[0]->inSyscall = false;
662
663 commitStatus[0] = TrapPending;
664
665 // Generate trap squash event.
666 generateTrapEvent(0);
667
668 // Clear the interrupt now that it's been handled
669 toIEW->commitInfo[0].clearInterrupt = true;
670 interrupt = NoFault;
671 } else {
672 DPRINTF(Commit, "Interrupt pending, waiting for ROB to empty.\n");
673 }
674 } else if (cpu->checkInterrupts &&
675 cpu->check_interrupts(cpu->tcBase(0)) &&
676 commitStatus[0] != TrapPending &&
677 !trapSquash[0] &&
678 !tcSquash[0]) {
679 // Process interrupts if interrupts are enabled, not in PAL
680 // mode, and no other traps or external squashes are currently
681 // pending.
682 // @todo: Allow other threads to handle interrupts.
683
684 // Get any interrupt that happened
685 interrupt = cpu->getInterrupts();
686
687 if (interrupt != NoFault) {
688 // Tell fetch that there is an interrupt pending. This
689 // will make fetch wait until it sees a non PAL-mode PC,
690 // at which point it stops fetching instructions.
691 toIEW->commitInfo[0].interruptPending = true;
692 }
693 }
694
695#endif // FULL_SYSTEM
696
697 ////////////////////////////////////
698 // Check for any possible squashes, handle them first
699 ////////////////////////////////////
700 std::list<unsigned>::iterator threads = activeThreads->begin();
701 std::list<unsigned>::iterator end = activeThreads->end();
702
703 while (threads != end) {
704 unsigned tid = *threads++;
705
706 // Not sure which one takes priority. I think if we have
707 // both, that's a bad sign.
708 if (trapSquash[tid] == true) {
709 assert(!tcSquash[tid]);
710 squashFromTrap(tid);
711 } else if (tcSquash[tid] == true) {
712 squashFromTC(tid);
713 }
714
715 // Squashed sequence number must be older than youngest valid
716 // instruction in the ROB. This prevents squashes from younger
717 // instructions overriding squashes from older instructions.
718 if (fromIEW->squash[tid] &&
719 commitStatus[tid] != TrapPending &&
720 fromIEW->squashedSeqNum[tid] <= youngestSeqNum[tid]) {
721
722 DPRINTF(Commit, "[tid:%i]: Squashing due to PC %#x [sn:%i]\n",
723 tid,
724 fromIEW->mispredPC[tid],
725 fromIEW->squashedSeqNum[tid]);
726
727 DPRINTF(Commit, "[tid:%i]: Redirecting to PC %#x\n",
728 tid,
729 fromIEW->nextPC[tid]);
730
731 commitStatus[tid] = ROBSquashing;
732
733 // If we want to include the squashing instruction in the squash,
734 // then use one older sequence number.
735 InstSeqNum squashed_inst = fromIEW->squashedSeqNum[tid];
736
737#if ISA_HAS_DELAY_SLOT
738 InstSeqNum bdelay_done_seq_num;
739 bool squash_bdelay_slot;
740
741 if (fromIEW->branchMispredict[tid]) {
742 if (fromIEW->branchTaken[tid] &&
743 fromIEW->condDelaySlotBranch[tid]) {
744 DPRINTF(Commit, "[tid:%i]: Cond. delay slot branch"
745 "mispredicted as taken. Squashing after previous "
746 "inst, [sn:%i]\n",
747 tid, squashed_inst);
748 bdelay_done_seq_num = squashed_inst;
749 squash_bdelay_slot = true;
750 } else {
751 DPRINTF(Commit, "[tid:%i]: Branch Mispredict. Squashing "
752 "after delay slot [sn:%i]\n", tid, squashed_inst+1);
753 bdelay_done_seq_num = squashed_inst + 1;
754 squash_bdelay_slot = false;
755 }
756 } else {
757 bdelay_done_seq_num = squashed_inst;
758 squash_bdelay_slot = true;
759 }
760#endif
761
762 if (fromIEW->includeSquashInst[tid] == true) {
763 squashed_inst--;
764#if ISA_HAS_DELAY_SLOT
765 bdelay_done_seq_num--;
766#endif
767 }
768 // All younger instructions will be squashed. Set the sequence
769 // number as the youngest instruction in the ROB.
770 youngestSeqNum[tid] = squashed_inst;
771
772#if ISA_HAS_DELAY_SLOT
773 rob->squash(bdelay_done_seq_num, tid);
774 toIEW->commitInfo[tid].squashDelaySlot = squash_bdelay_slot;
775 toIEW->commitInfo[tid].bdelayDoneSeqNum = bdelay_done_seq_num;
776#else
777 rob->squash(squashed_inst, tid);
778 toIEW->commitInfo[tid].squashDelaySlot = true;
779#endif
780 changedROBNumEntries[tid] = true;
781
782 toIEW->commitInfo[tid].doneSeqNum = squashed_inst;
783
784 toIEW->commitInfo[tid].squash = true;
785
786 // Send back the rob squashing signal so other stages know that
787 // the ROB is in the process of squashing.
788 toIEW->commitInfo[tid].robSquashing = true;
789
790 toIEW->commitInfo[tid].branchMispredict =
791 fromIEW->branchMispredict[tid];
792
793 toIEW->commitInfo[tid].branchTaken =
794 fromIEW->branchTaken[tid];
795
796 toIEW->commitInfo[tid].nextPC = fromIEW->nextPC[tid];
797
798 toIEW->commitInfo[tid].mispredPC = fromIEW->mispredPC[tid];
799
800 if (toIEW->commitInfo[tid].branchMispredict) {
801 ++branchMispredicts;
802 }
803 }
804
805 }
806
807 setNextStatus();
808
809 if (squashCounter != numThreads) {
810 // If we're not currently squashing, then get instructions.
811 getInsts();
812
813 // Try to commit any instructions.
814 commitInsts();
815 } else {
816#if ISA_HAS_DELAY_SLOT
817 skidInsert();
818#endif
819 }
820
821 //Check for any activity
822 threads = activeThreads->begin();
823
824 while (threads != end) {
825 unsigned tid = *threads++;
826
827 if (changedROBNumEntries[tid]) {
828 toIEW->commitInfo[tid].usedROB = true;
829 toIEW->commitInfo[tid].freeROBEntries = rob->numFreeEntries(tid);
830
831 if (rob->isEmpty(tid)) {
832 toIEW->commitInfo[tid].emptyROB = true;
833 }
834
835 wroteToTimeBuffer = true;
836 changedROBNumEntries[tid] = false;
837 }
838 }
839}
840
841template <class Impl>
842void
843DefaultCommit<Impl>::commitInsts()
844{
845 ////////////////////////////////////
846 // Handle commit
847 // Note that commit will be handled prior to putting new
848 // instructions in the ROB so that the ROB only tries to commit
849 // instructions it has in this current cycle, and not instructions
850 // it is writing in during this cycle. Can't commit and squash
851 // things at the same time...
852 ////////////////////////////////////
853
854 DPRINTF(Commit, "Trying to commit instructions in the ROB.\n");
855
856 unsigned num_committed = 0;
857
858 DynInstPtr head_inst;
859
860 // Commit as many instructions as possible until the commit bandwidth
861 // limit is reached, or it becomes impossible to commit any more.
862 while (num_committed < commitWidth) {
863 int commit_thread = getCommittingThread();
864
865 if (commit_thread == -1 || !rob->isHeadReady(commit_thread))
866 break;
867
868 head_inst = rob->readHeadInst(commit_thread);
869
870 int tid = head_inst->threadNumber;
871
872 assert(tid == commit_thread);
873
874 DPRINTF(Commit, "Trying to commit head instruction, [sn:%i] [tid:%i]\n",
875 head_inst->seqNum, tid);
876
877 // If the head instruction is squashed, it is ready to retire
878 // (be removed from the ROB) at any time.
879 if (head_inst->isSquashed()) {
880
881 DPRINTF(Commit, "Retiring squashed instruction from "
882 "ROB.\n");
883
884 rob->retireHead(commit_thread);
885
886 ++commitSquashedInsts;
887
888 // Record that the number of ROB entries has changed.
889 changedROBNumEntries[tid] = true;
890 } else {
891 PC[tid] = head_inst->readPC();
892 nextPC[tid] = head_inst->readNextPC();
893 nextNPC[tid] = head_inst->readNextNPC();
894
895 // Increment the total number of non-speculative instructions
896 // executed.
897 // Hack for now: it really shouldn't happen until after the
898 // commit is deemed to be successful, but this count is needed
899 // for syscalls.
900 thread[tid]->funcExeInst++;
901
902 // Try to commit the head instruction.
903 bool commit_success = commitHead(head_inst, num_committed);
904
905 if (commit_success) {
906 ++num_committed;
907
908 changedROBNumEntries[tid] = true;
909
910 // Set the doneSeqNum to the youngest committed instruction.
911 toIEW->commitInfo[tid].doneSeqNum = head_inst->seqNum;
912
913 ++commitCommittedInsts;
914
915 // To match the old model, don't count nops and instruction
916 // prefetches towards the total commit count.
917 if (!head_inst->isNop() && !head_inst->isInstPrefetch()) {
918 cpu->instDone(tid);
919 }
920
921 PC[tid] = nextPC[tid];
922#if ISA_HAS_DELAY_SLOT
923 nextPC[tid] = nextNPC[tid];
924 nextNPC[tid] = nextNPC[tid] + sizeof(TheISA::MachInst);
925#else
926 nextPC[tid] = nextPC[tid] + sizeof(TheISA::MachInst);
927#endif
928
929#if FULL_SYSTEM
930 int count = 0;
931 Addr oldpc;
932 do {
933 // Debug statement. Checks to make sure we're not
934 // currently updating state while handling PC events.
935 if (count == 0)
936 assert(!thread[tid]->inSyscall &&
937 !thread[tid]->trapPending);
938 oldpc = PC[tid];
939 cpu->system->pcEventQueue.service(
940 thread[tid]->getTC());
941 count++;
942 } while (oldpc != PC[tid]);
943 if (count > 1) {
944 DPRINTF(Commit, "PC skip function event, stopping commit\n");
945 break;
946 }
947#endif
948 } else {
949 DPRINTF(Commit, "Unable to commit head instruction PC:%#x "
950 "[tid:%i] [sn:%i].\n",
951 head_inst->readPC(), tid ,head_inst->seqNum);
952 break;
953 }
954 }
955 }
956
957 DPRINTF(CommitRate, "%i\n", num_committed);
958 numCommittedDist.sample(num_committed);
959
960 if (num_committed == commitWidth) {
961 commitEligibleSamples++;
962 }
963}
964
965template <class Impl>
966bool
967DefaultCommit<Impl>::commitHead(DynInstPtr &head_inst, unsigned inst_num)
968{
969 assert(head_inst);
970
971 int tid = head_inst->threadNumber;
972
973 // If the instruction is not executed yet, then it will need extra
974 // handling. Signal backwards that it should be executed.
975 if (!head_inst->isExecuted()) {
976 // Keep this number correct. We have not yet actually executed
977 // and committed this instruction.
978 thread[tid]->funcExeInst--;
979
980 head_inst->setAtCommit();
981
982 if (head_inst->isNonSpeculative() ||
983 head_inst->isStoreConditional() ||
984 head_inst->isMemBarrier() ||
985 head_inst->isWriteBarrier()) {
986
987 DPRINTF(Commit, "Encountered a barrier or non-speculative "
988 "instruction [sn:%lli] at the head of the ROB, PC %#x.\n",
989 head_inst->seqNum, head_inst->readPC());
990
|
1005 }
1006
1007 toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum;
1008
1009 // Change the instruction so it won't try to commit again until
1010 // it is executed.
1011 head_inst->clearCanCommit();
1012
1013 ++commitNonSpecStalls;
1014
1015 return false;
1016 } else if (head_inst->isLoad()) {
1017 DPRINTF(Commit, "[sn:%lli]: Uncached load, PC %#x.\n",
1018 head_inst->seqNum, head_inst->readPC());
1019
1020 // Send back the non-speculative instruction's sequence
1021 // number. Tell the lsq to re-execute the load.
1022 toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum;
1023 toIEW->commitInfo[tid].uncached = true;
1024 toIEW->commitInfo[tid].uncachedLoad = head_inst;
1025
1026 head_inst->clearCanCommit();
1027
1028 return false;
1029 } else {
1030 panic("Trying to commit un-executed instruction "
1031 "of unknown type!\n");
1032 }
1033 }
1034
1035 if (head_inst->isThreadSync()) {
1036 // Not handled for now.
1037 panic("Thread sync instructions are not handled yet.\n");
1038 }
1039
1040 // Stores mark themselves as completed.
1041 if (!head_inst->isStore()) {
1042 head_inst->setCompleted();
1043 }
1044
1045#if USE_CHECKER
1046 // Use checker prior to updating anything due to traps or PC
1047 // based events.
1048 if (cpu->checker) {
1049 cpu->checker->verify(head_inst);
1050 }
1051#endif
1052
1053 // Check if the instruction caused a fault. If so, trap.
1054 Fault inst_fault = head_inst->getFault();
1055
1056 // DTB will sometimes need the machine instruction for when
1057 // faults happen. So we will set it here, prior to the DTB
1058 // possibly needing it for its fault.
1059 thread[tid]->setInst(
1060 static_cast<TheISA::MachInst>(head_inst->staticInst->machInst));
1061
1062 if (inst_fault != NoFault) {
1063 head_inst->setCompleted();
1064 DPRINTF(Commit, "Inst [sn:%lli] PC %#x has a fault\n",
1065 head_inst->seqNum, head_inst->readPC());
1066
1067 if (iewStage->hasStoresToWB() || inst_num > 0) {
1068 DPRINTF(Commit, "Stores outstanding, fault must wait.\n");
1069 return false;
1070 }
1071
1072#if USE_CHECKER
1073 if (cpu->checker && head_inst->isStore()) {
1074 cpu->checker->verify(head_inst);
1075 }
1076#endif
1077
1078 assert(!thread[tid]->inSyscall);
1079
1080 // Mark that we're in state update mode so that the trap's
1081 // execution doesn't generate extra squashes.
1082 thread[tid]->inSyscall = true;
1083
1084 // Execute the trap. Although it's slightly unrealistic in
1085 // terms of timing (as it doesn't wait for the full timing of
1086 // the trap event to complete before updating state), it's
1087 // needed to update the state as soon as possible. This
1088 // prevents external agents from changing any specific state
1089 // that the trap need.
1090 cpu->trap(inst_fault, tid);
1091
1092 // Exit state update mode to avoid accidental updating.
1093 thread[tid]->inSyscall = false;
1094
1095 commitStatus[tid] = TrapPending;
1096
1097 // Generate trap squash event.
1098 generateTrapEvent(tid);
1099// warn("%lli fault (%d) handled @ PC %08p", curTick, inst_fault->name(), head_inst->readPC());
1100 return false;
1101 }
1102
1103 updateComInstStats(head_inst);
1104
1105#if FULL_SYSTEM
1106 if (thread[tid]->profile) {
1107// bool usermode = TheISA::inUserMode(thread[tid]->getTC());
1108// thread[tid]->profilePC = usermode ? 1 : head_inst->readPC();
1109 thread[tid]->profilePC = head_inst->readPC();
1110 ProfileNode *node = thread[tid]->profile->consume(thread[tid]->getTC(),
1111 head_inst->staticInst);
1112
1113 if (node)
1114 thread[tid]->profileNode = node;
1115 }
1116#endif
1117
1118 if (head_inst->traceData) {
1119 head_inst->traceData->setFetchSeq(head_inst->seqNum);
1120 head_inst->traceData->setCPSeq(thread[tid]->numInst);
1121 head_inst->traceData->finalize();
1122 head_inst->traceData = NULL;
1123 }
1124
1125 // Update the commit rename map
1126 for (int i = 0; i < head_inst->numDestRegs(); i++) {
1127 renameMap[tid]->setEntry(head_inst->destRegIdx(i),
1128 head_inst->renamedDestRegIdx(i));
1129 }
1130
1131 if (head_inst->isCopy())
1132 panic("Should not commit any copy instructions!");
1133
1134 // Finally clear the head ROB entry.
1135 rob->retireHead(tid);
1136
1137 // Return true to indicate that we have committed an instruction.
1138 return true;
1139}
1140
1141template <class Impl>
1142void
1143DefaultCommit<Impl>::getInsts()
1144{
1145 DPRINTF(Commit, "Getting instructions from Rename stage.\n");
1146
1147#if ISA_HAS_DELAY_SLOT
1148 // Read any renamed instructions and place them into the ROB.
1149 int insts_to_process = std::min((int)renameWidth,
1150 (int)(fromRename->size + skidBuffer.size()));
1151 int rename_idx = 0;
1152
1153 DPRINTF(Commit, "%i insts available to process. Rename Insts:%i "
1154 "SkidBuffer Insts:%i\n", insts_to_process, fromRename->size,
1155 skidBuffer.size());
1156#else
1157 // Read any renamed instructions and place them into the ROB.
1158 int insts_to_process = std::min((int)renameWidth, fromRename->size);
1159#endif
1160
1161
1162 for (int inst_num = 0; inst_num < insts_to_process; ++inst_num) {
1163 DynInstPtr inst;
1164
1165#if ISA_HAS_DELAY_SLOT
1166 // Get insts from skidBuffer or from Rename
1167 if (skidBuffer.size() > 0) {
1168 DPRINTF(Commit, "Grabbing skidbuffer inst.\n");
1169 inst = skidBuffer.front();
1170 skidBuffer.pop();
1171 } else {
1172 DPRINTF(Commit, "Grabbing rename inst.\n");
1173 inst = fromRename->insts[rename_idx++];
1174 }
1175#else
1176 inst = fromRename->insts[inst_num];
1177#endif
1178 int tid = inst->threadNumber;
1179
1180 if (!inst->isSquashed() &&
1181 commitStatus[tid] != ROBSquashing) {
1182 changedROBNumEntries[tid] = true;
1183
1184 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ROB.\n",
1185 inst->readPC(), inst->seqNum, tid);
1186
1187 rob->insertInst(inst);
1188
1189 assert(rob->getThreadEntries(tid) <= rob->getMaxEntries(tid));
1190
1191 youngestSeqNum[tid] = inst->seqNum;
1192 } else {
1193 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was "
1194 "squashed, skipping.\n",
1195 inst->readPC(), inst->seqNum, tid);
1196 }
1197 }
1198
1199#if ISA_HAS_DELAY_SLOT
1200 if (rename_idx < fromRename->size) {
1201 DPRINTF(Commit,"Placing Rename Insts into skidBuffer.\n");
1202
1203 for (;
1204 rename_idx < fromRename->size;
1205 rename_idx++) {
1206 DynInstPtr inst = fromRename->insts[rename_idx];
1207
1208 if (!inst->isSquashed()) {
1209 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ",
1210 "skidBuffer.\n", inst->readPC(), inst->seqNum,
1211 inst->threadNumber);
1212 skidBuffer.push(inst);
1213 } else {
1214 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was "
1215 "squashed, skipping.\n",
1216 inst->readPC(), inst->seqNum, inst->threadNumber);
1217 }
1218 }
1219 }
1220#endif
1221
1222}
1223
1224template <class Impl>
1225void
1226DefaultCommit<Impl>::skidInsert()
1227{
1228 DPRINTF(Commit, "Attempting to any instructions from rename into "
1229 "skidBuffer.\n");
1230
1231 for (int inst_num = 0; inst_num < fromRename->size; ++inst_num) {
1232 DynInstPtr inst = fromRename->insts[inst_num];
1233
1234 if (!inst->isSquashed()) {
1235 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ",
1236 "skidBuffer.\n", inst->readPC(), inst->seqNum,
1237 inst->threadNumber);
1238 skidBuffer.push(inst);
1239 } else {
1240 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was "
1241 "squashed, skipping.\n",
1242 inst->readPC(), inst->seqNum, inst->threadNumber);
1243 }
1244 }
1245}
1246
1247template <class Impl>
1248void
1249DefaultCommit<Impl>::markCompletedInsts()
1250{
1251 // Grab completed insts out of the IEW instruction queue, and mark
1252 // instructions completed within the ROB.
1253 for (int inst_num = 0;
1254 inst_num < fromIEW->size && fromIEW->insts[inst_num];
1255 ++inst_num)
1256 {
1257 if (!fromIEW->insts[inst_num]->isSquashed()) {
1258 DPRINTF(Commit, "[tid:%i]: Marking PC %#x, [sn:%lli] ready "
1259 "within ROB.\n",
1260 fromIEW->insts[inst_num]->threadNumber,
1261 fromIEW->insts[inst_num]->readPC(),
1262 fromIEW->insts[inst_num]->seqNum);
1263
1264 // Mark the instruction as ready to commit.
1265 fromIEW->insts[inst_num]->setCanCommit();
1266 }
1267 }
1268}
1269
1270template <class Impl>
1271bool
1272DefaultCommit<Impl>::robDoneSquashing()
1273{
1274 std::list<unsigned>::iterator threads = activeThreads->begin();
1275 std::list<unsigned>::iterator end = activeThreads->end();
1276
1277 while (threads != end) {
1278 unsigned tid = *threads++;
1279
1280 if (!rob->isDoneSquashing(tid))
1281 return false;
1282 }
1283
1284 return true;
1285}
1286
1287template <class Impl>
1288void
1289DefaultCommit<Impl>::updateComInstStats(DynInstPtr &inst)
1290{
1291 unsigned thread = inst->threadNumber;
1292
1293 //
1294 // Pick off the software prefetches
1295 //
1296#ifdef TARGET_ALPHA
1297 if (inst->isDataPrefetch()) {
1298 statComSwp[thread]++;
1299 } else {
1300 statComInst[thread]++;
1301 }
1302#else
1303 statComInst[thread]++;
1304#endif
1305
1306 //
1307 // Control Instructions
1308 //
1309 if (inst->isControl())
1310 statComBranches[thread]++;
1311
1312 //
1313 // Memory references
1314 //
1315 if (inst->isMemRef()) {
1316 statComRefs[thread]++;
1317
1318 if (inst->isLoad()) {
1319 statComLoads[thread]++;
1320 }
1321 }
1322
1323 if (inst->isMemBarrier()) {
1324 statComMembars[thread]++;
1325 }
1326}
1327
1328////////////////////////////////////////
1329// //
1330// SMT COMMIT POLICY MAINTAINED HERE //
1331// //
1332////////////////////////////////////////
1333template <class Impl>
1334int
1335DefaultCommit<Impl>::getCommittingThread()
1336{
1337 if (numThreads > 1) {
1338 switch (commitPolicy) {
1339
1340 case Aggressive:
1341 //If Policy is Aggressive, commit will call
1342 //this function multiple times per
1343 //cycle
1344 return oldestReady();
1345
1346 case RoundRobin:
1347 return roundRobin();
1348
1349 case OldestReady:
1350 return oldestReady();
1351
1352 default:
1353 return -1;
1354 }
1355 } else {
1356 assert(!activeThreads->empty());
1357 int tid = activeThreads->front();
1358
1359 if (commitStatus[tid] == Running ||
1360 commitStatus[tid] == Idle ||
1361 commitStatus[tid] == FetchTrapPending) {
1362 return tid;
1363 } else {
1364 return -1;
1365 }
1366 }
1367}
1368
1369template<class Impl>
1370int
1371DefaultCommit<Impl>::roundRobin()
1372{
1373 std::list<unsigned>::iterator pri_iter = priority_list.begin();
1374 std::list<unsigned>::iterator end = priority_list.end();
1375
1376 while (pri_iter != end) {
1377 unsigned tid = *pri_iter;
1378
1379 if (commitStatus[tid] == Running ||
1380 commitStatus[tid] == Idle ||
1381 commitStatus[tid] == FetchTrapPending) {
1382
1383 if (rob->isHeadReady(tid)) {
1384 priority_list.erase(pri_iter);
1385 priority_list.push_back(tid);
1386
1387 return tid;
1388 }
1389 }
1390
1391 pri_iter++;
1392 }
1393
1394 return -1;
1395}
1396
1397template<class Impl>
1398int
1399DefaultCommit<Impl>::oldestReady()
1400{
1401 unsigned oldest = 0;
1402 bool first = true;
1403
1404 std::list<unsigned>::iterator threads = activeThreads->begin();
1405 std::list<unsigned>::iterator end = activeThreads->end();
1406
1407 while (threads != end) {
1408 unsigned tid = *threads++;
1409
1410 if (!rob->isEmpty(tid) &&
1411 (commitStatus[tid] == Running ||
1412 commitStatus[tid] == Idle ||
1413 commitStatus[tid] == FetchTrapPending)) {
1414
1415 if (rob->isHeadReady(tid)) {
1416
1417 DynInstPtr head_inst = rob->readHeadInst(tid);
1418
1419 if (first) {
1420 oldest = tid;
1421 first = false;
1422 } else if (head_inst->seqNum < oldest) {
1423 oldest = tid;
1424 }
1425 }
1426 }
1427 }
1428
1429 if (!first) {
1430 return oldest;
1431 } else {
1432 return -1;
1433 }
1434}
| 1004 }
1005
1006 toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum;
1007
1008 // Change the instruction so it won't try to commit again until
1009 // it is executed.
1010 head_inst->clearCanCommit();
1011
1012 ++commitNonSpecStalls;
1013
1014 return false;
1015 } else if (head_inst->isLoad()) {
1016 DPRINTF(Commit, "[sn:%lli]: Uncached load, PC %#x.\n",
1017 head_inst->seqNum, head_inst->readPC());
1018
1019 // Send back the non-speculative instruction's sequence
1020 // number. Tell the lsq to re-execute the load.
1021 toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum;
1022 toIEW->commitInfo[tid].uncached = true;
1023 toIEW->commitInfo[tid].uncachedLoad = head_inst;
1024
1025 head_inst->clearCanCommit();
1026
1027 return false;
1028 } else {
1029 panic("Trying to commit un-executed instruction "
1030 "of unknown type!\n");
1031 }
1032 }
1033
1034 if (head_inst->isThreadSync()) {
1035 // Not handled for now.
1036 panic("Thread sync instructions are not handled yet.\n");
1037 }
1038
1039 // Stores mark themselves as completed.
1040 if (!head_inst->isStore()) {
1041 head_inst->setCompleted();
1042 }
1043
1044#if USE_CHECKER
1045 // Use checker prior to updating anything due to traps or PC
1046 // based events.
1047 if (cpu->checker) {
1048 cpu->checker->verify(head_inst);
1049 }
1050#endif
1051
1052 // Check if the instruction caused a fault. If so, trap.
1053 Fault inst_fault = head_inst->getFault();
1054
1055 // DTB will sometimes need the machine instruction for when
1056 // faults happen. So we will set it here, prior to the DTB
1057 // possibly needing it for its fault.
1058 thread[tid]->setInst(
1059 static_cast<TheISA::MachInst>(head_inst->staticInst->machInst));
1060
1061 if (inst_fault != NoFault) {
1062 head_inst->setCompleted();
1063 DPRINTF(Commit, "Inst [sn:%lli] PC %#x has a fault\n",
1064 head_inst->seqNum, head_inst->readPC());
1065
1066 if (iewStage->hasStoresToWB() || inst_num > 0) {
1067 DPRINTF(Commit, "Stores outstanding, fault must wait.\n");
1068 return false;
1069 }
1070
1071#if USE_CHECKER
1072 if (cpu->checker && head_inst->isStore()) {
1073 cpu->checker->verify(head_inst);
1074 }
1075#endif
1076
1077 assert(!thread[tid]->inSyscall);
1078
1079 // Mark that we're in state update mode so that the trap's
1080 // execution doesn't generate extra squashes.
1081 thread[tid]->inSyscall = true;
1082
1083 // Execute the trap. Although it's slightly unrealistic in
1084 // terms of timing (as it doesn't wait for the full timing of
1085 // the trap event to complete before updating state), it's
1086 // needed to update the state as soon as possible. This
1087 // prevents external agents from changing any specific state
1088 // that the trap need.
1089 cpu->trap(inst_fault, tid);
1090
1091 // Exit state update mode to avoid accidental updating.
1092 thread[tid]->inSyscall = false;
1093
1094 commitStatus[tid] = TrapPending;
1095
1096 // Generate trap squash event.
1097 generateTrapEvent(tid);
1098// warn("%lli fault (%d) handled @ PC %08p", curTick, inst_fault->name(), head_inst->readPC());
1099 return false;
1100 }
1101
1102 updateComInstStats(head_inst);
1103
1104#if FULL_SYSTEM
1105 if (thread[tid]->profile) {
1106// bool usermode = TheISA::inUserMode(thread[tid]->getTC());
1107// thread[tid]->profilePC = usermode ? 1 : head_inst->readPC();
1108 thread[tid]->profilePC = head_inst->readPC();
1109 ProfileNode *node = thread[tid]->profile->consume(thread[tid]->getTC(),
1110 head_inst->staticInst);
1111
1112 if (node)
1113 thread[tid]->profileNode = node;
1114 }
1115#endif
1116
1117 if (head_inst->traceData) {
1118 head_inst->traceData->setFetchSeq(head_inst->seqNum);
1119 head_inst->traceData->setCPSeq(thread[tid]->numInst);
1120 head_inst->traceData->finalize();
1121 head_inst->traceData = NULL;
1122 }
1123
1124 // Update the commit rename map
1125 for (int i = 0; i < head_inst->numDestRegs(); i++) {
1126 renameMap[tid]->setEntry(head_inst->destRegIdx(i),
1127 head_inst->renamedDestRegIdx(i));
1128 }
1129
1130 if (head_inst->isCopy())
1131 panic("Should not commit any copy instructions!");
1132
1133 // Finally clear the head ROB entry.
1134 rob->retireHead(tid);
1135
1136 // Return true to indicate that we have committed an instruction.
1137 return true;
1138}
1139
1140template <class Impl>
1141void
1142DefaultCommit<Impl>::getInsts()
1143{
1144 DPRINTF(Commit, "Getting instructions from Rename stage.\n");
1145
1146#if ISA_HAS_DELAY_SLOT
1147 // Read any renamed instructions and place them into the ROB.
1148 int insts_to_process = std::min((int)renameWidth,
1149 (int)(fromRename->size + skidBuffer.size()));
1150 int rename_idx = 0;
1151
1152 DPRINTF(Commit, "%i insts available to process. Rename Insts:%i "
1153 "SkidBuffer Insts:%i\n", insts_to_process, fromRename->size,
1154 skidBuffer.size());
1155#else
1156 // Read any renamed instructions and place them into the ROB.
1157 int insts_to_process = std::min((int)renameWidth, fromRename->size);
1158#endif
1159
1160
1161 for (int inst_num = 0; inst_num < insts_to_process; ++inst_num) {
1162 DynInstPtr inst;
1163
1164#if ISA_HAS_DELAY_SLOT
1165 // Get insts from skidBuffer or from Rename
1166 if (skidBuffer.size() > 0) {
1167 DPRINTF(Commit, "Grabbing skidbuffer inst.\n");
1168 inst = skidBuffer.front();
1169 skidBuffer.pop();
1170 } else {
1171 DPRINTF(Commit, "Grabbing rename inst.\n");
1172 inst = fromRename->insts[rename_idx++];
1173 }
1174#else
1175 inst = fromRename->insts[inst_num];
1176#endif
1177 int tid = inst->threadNumber;
1178
1179 if (!inst->isSquashed() &&
1180 commitStatus[tid] != ROBSquashing) {
1181 changedROBNumEntries[tid] = true;
1182
1183 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ROB.\n",
1184 inst->readPC(), inst->seqNum, tid);
1185
1186 rob->insertInst(inst);
1187
1188 assert(rob->getThreadEntries(tid) <= rob->getMaxEntries(tid));
1189
1190 youngestSeqNum[tid] = inst->seqNum;
1191 } else {
1192 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was "
1193 "squashed, skipping.\n",
1194 inst->readPC(), inst->seqNum, tid);
1195 }
1196 }
1197
1198#if ISA_HAS_DELAY_SLOT
1199 if (rename_idx < fromRename->size) {
1200 DPRINTF(Commit,"Placing Rename Insts into skidBuffer.\n");
1201
1202 for (;
1203 rename_idx < fromRename->size;
1204 rename_idx++) {
1205 DynInstPtr inst = fromRename->insts[rename_idx];
1206
1207 if (!inst->isSquashed()) {
1208 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ",
1209 "skidBuffer.\n", inst->readPC(), inst->seqNum,
1210 inst->threadNumber);
1211 skidBuffer.push(inst);
1212 } else {
1213 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was "
1214 "squashed, skipping.\n",
1215 inst->readPC(), inst->seqNum, inst->threadNumber);
1216 }
1217 }
1218 }
1219#endif
1220
1221}
1222
1223template <class Impl>
1224void
1225DefaultCommit<Impl>::skidInsert()
1226{
1227 DPRINTF(Commit, "Attempting to any instructions from rename into "
1228 "skidBuffer.\n");
1229
1230 for (int inst_num = 0; inst_num < fromRename->size; ++inst_num) {
1231 DynInstPtr inst = fromRename->insts[inst_num];
1232
1233 if (!inst->isSquashed()) {
1234 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ",
1235 "skidBuffer.\n", inst->readPC(), inst->seqNum,
1236 inst->threadNumber);
1237 skidBuffer.push(inst);
1238 } else {
1239 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was "
1240 "squashed, skipping.\n",
1241 inst->readPC(), inst->seqNum, inst->threadNumber);
1242 }
1243 }
1244}
1245
1246template <class Impl>
1247void
1248DefaultCommit<Impl>::markCompletedInsts()
1249{
1250 // Grab completed insts out of the IEW instruction queue, and mark
1251 // instructions completed within the ROB.
1252 for (int inst_num = 0;
1253 inst_num < fromIEW->size && fromIEW->insts[inst_num];
1254 ++inst_num)
1255 {
1256 if (!fromIEW->insts[inst_num]->isSquashed()) {
1257 DPRINTF(Commit, "[tid:%i]: Marking PC %#x, [sn:%lli] ready "
1258 "within ROB.\n",
1259 fromIEW->insts[inst_num]->threadNumber,
1260 fromIEW->insts[inst_num]->readPC(),
1261 fromIEW->insts[inst_num]->seqNum);
1262
1263 // Mark the instruction as ready to commit.
1264 fromIEW->insts[inst_num]->setCanCommit();
1265 }
1266 }
1267}
1268
1269template <class Impl>
1270bool
1271DefaultCommit<Impl>::robDoneSquashing()
1272{
1273 std::list<unsigned>::iterator threads = activeThreads->begin();
1274 std::list<unsigned>::iterator end = activeThreads->end();
1275
1276 while (threads != end) {
1277 unsigned tid = *threads++;
1278
1279 if (!rob->isDoneSquashing(tid))
1280 return false;
1281 }
1282
1283 return true;
1284}
1285
1286template <class Impl>
1287void
1288DefaultCommit<Impl>::updateComInstStats(DynInstPtr &inst)
1289{
1290 unsigned thread = inst->threadNumber;
1291
1292 //
1293 // Pick off the software prefetches
1294 //
1295#ifdef TARGET_ALPHA
1296 if (inst->isDataPrefetch()) {
1297 statComSwp[thread]++;
1298 } else {
1299 statComInst[thread]++;
1300 }
1301#else
1302 statComInst[thread]++;
1303#endif
1304
1305 //
1306 // Control Instructions
1307 //
1308 if (inst->isControl())
1309 statComBranches[thread]++;
1310
1311 //
1312 // Memory references
1313 //
1314 if (inst->isMemRef()) {
1315 statComRefs[thread]++;
1316
1317 if (inst->isLoad()) {
1318 statComLoads[thread]++;
1319 }
1320 }
1321
1322 if (inst->isMemBarrier()) {
1323 statComMembars[thread]++;
1324 }
1325}
1326
1327////////////////////////////////////////
1328// //
1329// SMT COMMIT POLICY MAINTAINED HERE //
1330// //
1331////////////////////////////////////////
1332template <class Impl>
1333int
1334DefaultCommit<Impl>::getCommittingThread()
1335{
1336 if (numThreads > 1) {
1337 switch (commitPolicy) {
1338
1339 case Aggressive:
1340 //If Policy is Aggressive, commit will call
1341 //this function multiple times per
1342 //cycle
1343 return oldestReady();
1344
1345 case RoundRobin:
1346 return roundRobin();
1347
1348 case OldestReady:
1349 return oldestReady();
1350
1351 default:
1352 return -1;
1353 }
1354 } else {
1355 assert(!activeThreads->empty());
1356 int tid = activeThreads->front();
1357
1358 if (commitStatus[tid] == Running ||
1359 commitStatus[tid] == Idle ||
1360 commitStatus[tid] == FetchTrapPending) {
1361 return tid;
1362 } else {
1363 return -1;
1364 }
1365 }
1366}
1367
1368template<class Impl>
1369int
1370DefaultCommit<Impl>::roundRobin()
1371{
1372 std::list<unsigned>::iterator pri_iter = priority_list.begin();
1373 std::list<unsigned>::iterator end = priority_list.end();
1374
1375 while (pri_iter != end) {
1376 unsigned tid = *pri_iter;
1377
1378 if (commitStatus[tid] == Running ||
1379 commitStatus[tid] == Idle ||
1380 commitStatus[tid] == FetchTrapPending) {
1381
1382 if (rob->isHeadReady(tid)) {
1383 priority_list.erase(pri_iter);
1384 priority_list.push_back(tid);
1385
1386 return tid;
1387 }
1388 }
1389
1390 pri_iter++;
1391 }
1392
1393 return -1;
1394}
1395
1396template<class Impl>
1397int
1398DefaultCommit<Impl>::oldestReady()
1399{
1400 unsigned oldest = 0;
1401 bool first = true;
1402
1403 std::list<unsigned>::iterator threads = activeThreads->begin();
1404 std::list<unsigned>::iterator end = activeThreads->end();
1405
1406 while (threads != end) {
1407 unsigned tid = *threads++;
1408
1409 if (!rob->isEmpty(tid) &&
1410 (commitStatus[tid] == Running ||
1411 commitStatus[tid] == Idle ||
1412 commitStatus[tid] == FetchTrapPending)) {
1413
1414 if (rob->isHeadReady(tid)) {
1415
1416 DynInstPtr head_inst = rob->readHeadInst(tid);
1417
1418 if (first) {
1419 oldest = tid;
1420 first = false;
1421 } else if (head_inst->seqNum < oldest) {
1422 oldest = tid;
1423 }
1424 }
1425 }
1426 }
1427
1428 if (!first) {
1429 return oldest;
1430 } else {
1431 return -1;
1432 }
1433}
|