commit_impl.hh revision 5769:e53bdd0e4bf1
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 49#include "params/DerivO3CPU.hh" 50 51template <class Impl> 52DefaultCommit<Impl>::TrapEvent::TrapEvent(DefaultCommit<Impl> *_commit, 53 unsigned _tid) 54 : Event(CPU_Tick_Pri), commit(_commit), tid(_tid) 55{ 56 this->setFlags(AutoDelete); 57} 58 59template <class Impl> 60void 61DefaultCommit<Impl>::TrapEvent::process() 62{ 63 // This will get reset by commit if it was switched out at the 64 // time of this event processing. 65 commit->trapSquash[tid] = true; 66} 67 68template <class Impl> 69const char * 70DefaultCommit<Impl>::TrapEvent::description() const 71{ 72 return "Trap"; 73} 74 75template <class Impl> 76DefaultCommit<Impl>::DefaultCommit(O3CPU *_cpu, DerivO3CPUParams *params) 77 : cpu(_cpu), 78 squashCounter(0), 79 iewToCommitDelay(params->iewToCommitDelay), 80 commitToIEWDelay(params->commitToIEWDelay), 81 renameToROBDelay(params->renameToROBDelay), 82 fetchToCommitDelay(params->commitToFetchDelay), 83 renameWidth(params->renameWidth), 84 commitWidth(params->commitWidth), 85 numThreads(params->numThreads), 86 drainPending(false), 87 switchedOut(false), 88 trapLatency(params->trapLatency) 89{ 90 _status = Active; 91 _nextStatus = Inactive; 92 std::string policy = params->smtCommitPolicy; 93 94 //Convert string to lowercase 95 std::transform(policy.begin(), policy.end(), policy.begin(), 96 (int(*)(int)) tolower); 97 98 //Assign commit policy 99 if (policy == "aggressive"){ 100 commitPolicy = Aggressive; 101 102 DPRINTF(Commit,"Commit Policy set to Aggressive."); 103 } else if (policy == "roundrobin"){ 104 commitPolicy = RoundRobin; 105 106 //Set-Up Priority List 107 for (int tid=0; tid < numThreads; tid++) { 108 priority_list.push_back(tid); 109 } 110 111 DPRINTF(Commit,"Commit Policy set to Round Robin."); 112 } else if (policy == "oldestready"){ 113 commitPolicy = OldestReady; 114 115 DPRINTF(Commit,"Commit Policy set to Oldest Ready."); 116 } else { 117 assert(0 && "Invalid SMT Commit Policy. Options Are: {Aggressive," 118 "RoundRobin,OldestReady}"); 119 } 120 121 for (int i=0; i < numThreads; i++) { 122 commitStatus[i] = Idle; 123 changedROBNumEntries[i] = false; 124 checkEmptyROB[i] = false; 125 trapInFlight[i] = false; 126 committedStores[i] = false; 127 trapSquash[i] = false; 128 tcSquash[i] = false; 129 microPC[i] = nextMicroPC[i] = PC[i] = nextPC[i] = nextNPC[i] = 0; 130 } 131#if FULL_SYSTEM 132 interrupt = NoFault; 133#endif 134} 135 136template <class Impl> 137std::string 138DefaultCommit<Impl>::name() const 139{ 140 return cpu->name() + ".commit"; 141} 142 143template <class Impl> 144void 145DefaultCommit<Impl>::regStats() 146{ 147 using namespace Stats; 148 commitCommittedInsts 149 .name(name() + ".commitCommittedInsts") 150 .desc("The number of committed instructions") 151 .prereq(commitCommittedInsts); 152 commitSquashedInsts 153 .name(name() + ".commitSquashedInsts") 154 .desc("The number of squashed insts skipped by commit") 155 .prereq(commitSquashedInsts); 156 commitSquashEvents 157 .name(name() + ".commitSquashEvents") 158 .desc("The number of times commit is told to squash") 159 .prereq(commitSquashEvents); 160 commitNonSpecStalls 161 .name(name() + ".commitNonSpecStalls") 162 .desc("The number of times commit has been forced to stall to " 163 "communicate backwards") 164 .prereq(commitNonSpecStalls); 165 branchMispredicts 166 .name(name() + ".branchMispredicts") 167 .desc("The number of times a branch was mispredicted") 168 .prereq(branchMispredicts); 169 numCommittedDist 170 .init(0,commitWidth,1) 171 .name(name() + ".COM:committed_per_cycle") 172 .desc("Number of insts commited each cycle") 173 .flags(Stats::pdf) 174 ; 175 176 statComInst 177 .init(cpu->number_of_threads) 178 .name(name() + ".COM:count") 179 .desc("Number of instructions committed") 180 .flags(total) 181 ; 182 183 statComSwp 184 .init(cpu->number_of_threads) 185 .name(name() + ".COM:swp_count") 186 .desc("Number of s/w prefetches committed") 187 .flags(total) 188 ; 189 190 statComRefs 191 .init(cpu->number_of_threads) 192 .name(name() + ".COM:refs") 193 .desc("Number of memory references committed") 194 .flags(total) 195 ; 196 197 statComLoads 198 .init(cpu->number_of_threads) 199 .name(name() + ".COM:loads") 200 .desc("Number of loads committed") 201 .flags(total) 202 ; 203 204 statComMembars 205 .init(cpu->number_of_threads) 206 .name(name() + ".COM:membars") 207 .desc("Number of memory barriers committed") 208 .flags(total) 209 ; 210 211 statComBranches 212 .init(cpu->number_of_threads) 213 .name(name() + ".COM:branches") 214 .desc("Number of branches committed") 215 .flags(total) 216 ; 217 218 commitEligible 219 .init(cpu->number_of_threads) 220 .name(name() + ".COM:bw_limited") 221 .desc("number of insts not committed due to BW limits") 222 .flags(total) 223 ; 224 225 commitEligibleSamples 226 .name(name() + ".COM:bw_lim_events") 227 .desc("number cycles where commit BW limit reached") 228 ; 229} 230 231template <class Impl> 232void 233DefaultCommit<Impl>::setThreads(std::vector<Thread *> &threads) 234{ 235 thread = threads; 236} 237 238template <class Impl> 239void 240DefaultCommit<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) 241{ 242 timeBuffer = tb_ptr; 243 244 // Setup wire to send information back to IEW. 245 toIEW = timeBuffer->getWire(0); 246 247 // Setup wire to read data from IEW (for the ROB). 248 robInfoFromIEW = timeBuffer->getWire(-iewToCommitDelay); 249} 250 251template <class Impl> 252void 253DefaultCommit<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr) 254{ 255 fetchQueue = fq_ptr; 256 257 // Setup wire to get instructions from rename (for the ROB). 258 fromFetch = fetchQueue->getWire(-fetchToCommitDelay); 259} 260 261template <class Impl> 262void 263DefaultCommit<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) 264{ 265 renameQueue = rq_ptr; 266 267 // Setup wire to get instructions from rename (for the ROB). 268 fromRename = renameQueue->getWire(-renameToROBDelay); 269} 270 271template <class Impl> 272void 273DefaultCommit<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr) 274{ 275 iewQueue = iq_ptr; 276 277 // Setup wire to get instructions from IEW. 278 fromIEW = iewQueue->getWire(-iewToCommitDelay); 279} 280 281template <class Impl> 282void 283DefaultCommit<Impl>::setIEWStage(IEW *iew_stage) 284{ 285 iewStage = iew_stage; 286} 287 288template<class Impl> 289void 290DefaultCommit<Impl>::setActiveThreads(std::list<unsigned> *at_ptr) 291{ 292 activeThreads = at_ptr; 293} 294 295template <class Impl> 296void 297DefaultCommit<Impl>::setRenameMap(RenameMap rm_ptr[]) 298{ 299 for (int i=0; i < numThreads; i++) { 300 renameMap[i] = &rm_ptr[i]; 301 } 302} 303 304template <class Impl> 305void 306DefaultCommit<Impl>::setROB(ROB *rob_ptr) 307{ 308 rob = rob_ptr; 309} 310 311template <class Impl> 312void 313DefaultCommit<Impl>::initStage() 314{ 315 rob->setActiveThreads(activeThreads); 316 rob->resetEntries(); 317 318 // Broadcast the number of free entries. 319 for (int i=0; i < numThreads; i++) { 320 toIEW->commitInfo[i].usedROB = true; 321 toIEW->commitInfo[i].freeROBEntries = rob->numFreeEntries(i); 322 toIEW->commitInfo[i].emptyROB = true; 323 } 324 325 // Commit must broadcast the number of free entries it has at the 326 // start of the simulation, so it starts as active. 327 cpu->activateStage(O3CPU::CommitIdx); 328 329 cpu->activityThisCycle(); 330 trapLatency = cpu->ticks(trapLatency); 331} 332 333template <class Impl> 334bool 335DefaultCommit<Impl>::drain() 336{ 337 drainPending = true; 338 339 return false; 340} 341 342template <class Impl> 343void 344DefaultCommit<Impl>::switchOut() 345{ 346 switchedOut = true; 347 drainPending = false; 348 rob->switchOut(); 349} 350 351template <class Impl> 352void 353DefaultCommit<Impl>::resume() 354{ 355 drainPending = false; 356} 357 358template <class Impl> 359void 360DefaultCommit<Impl>::takeOverFrom() 361{ 362 switchedOut = false; 363 _status = Active; 364 _nextStatus = Inactive; 365 for (int i=0; i < numThreads; i++) { 366 commitStatus[i] = Idle; 367 changedROBNumEntries[i] = false; 368 trapSquash[i] = false; 369 tcSquash[i] = false; 370 } 371 squashCounter = 0; 372 rob->takeOverFrom(); 373} 374 375template <class Impl> 376void 377DefaultCommit<Impl>::updateStatus() 378{ 379 // reset ROB changed variable 380 std::list<unsigned>::iterator threads = activeThreads->begin(); 381 std::list<unsigned>::iterator end = activeThreads->end(); 382 383 while (threads != end) { 384 unsigned tid = *threads++; 385 386 changedROBNumEntries[tid] = false; 387 388 // Also check if any of the threads has a trap pending 389 if (commitStatus[tid] == TrapPending || 390 commitStatus[tid] == FetchTrapPending) { 391 _nextStatus = Active; 392 } 393 } 394 395 if (_nextStatus == Inactive && _status == Active) { 396 DPRINTF(Activity, "Deactivating stage.\n"); 397 cpu->deactivateStage(O3CPU::CommitIdx); 398 } else if (_nextStatus == Active && _status == Inactive) { 399 DPRINTF(Activity, "Activating stage.\n"); 400 cpu->activateStage(O3CPU::CommitIdx); 401 } 402 403 _status = _nextStatus; 404} 405 406template <class Impl> 407void 408DefaultCommit<Impl>::setNextStatus() 409{ 410 int squashes = 0; 411 412 std::list<unsigned>::iterator threads = activeThreads->begin(); 413 std::list<unsigned>::iterator end = activeThreads->end(); 414 415 while (threads != end) { 416 unsigned tid = *threads++; 417 418 if (commitStatus[tid] == ROBSquashing) { 419 squashes++; 420 } 421 } 422 423 squashCounter = squashes; 424 425 // If commit is currently squashing, then it will have activity for the 426 // next cycle. Set its next status as active. 427 if (squashCounter) { 428 _nextStatus = Active; 429 } 430} 431 432template <class Impl> 433bool 434DefaultCommit<Impl>::changedROBEntries() 435{ 436 std::list<unsigned>::iterator threads = activeThreads->begin(); 437 std::list<unsigned>::iterator end = activeThreads->end(); 438 439 while (threads != end) { 440 unsigned tid = *threads++; 441 442 if (changedROBNumEntries[tid]) { 443 return true; 444 } 445 } 446 447 return false; 448} 449 450template <class Impl> 451unsigned 452DefaultCommit<Impl>::numROBFreeEntries(unsigned tid) 453{ 454 return rob->numFreeEntries(tid); 455} 456 457template <class Impl> 458void 459DefaultCommit<Impl>::generateTrapEvent(unsigned tid) 460{ 461 DPRINTF(Commit, "Generating trap event for [tid:%i]\n", tid); 462 463 TrapEvent *trap = new TrapEvent(this, tid); 464 465 cpu->schedule(trap, curTick + trapLatency); 466 trapInFlight[tid] = true; 467} 468 469template <class Impl> 470void 471DefaultCommit<Impl>::generateTCEvent(unsigned tid) 472{ 473 assert(!trapInFlight[tid]); 474 DPRINTF(Commit, "Generating TC squash event for [tid:%i]\n", tid); 475 476 tcSquash[tid] = true; 477} 478 479template <class Impl> 480void 481DefaultCommit<Impl>::squashAll(unsigned tid) 482{ 483 // If we want to include the squashing instruction in the squash, 484 // then use one older sequence number. 485 // Hopefully this doesn't mess things up. Basically I want to squash 486 // all instructions of this thread. 487 InstSeqNum squashed_inst = rob->isEmpty() ? 488 0 : rob->readHeadInst(tid)->seqNum - 1; 489 490 // All younger instructions will be squashed. Set the sequence 491 // number as the youngest instruction in the ROB (0 in this case. 492 // Hopefully nothing breaks.) 493 youngestSeqNum[tid] = 0; 494 495 rob->squash(squashed_inst, tid); 496 changedROBNumEntries[tid] = true; 497 498 // Send back the sequence number of the squashed instruction. 499 toIEW->commitInfo[tid].doneSeqNum = squashed_inst; 500 501 // Send back the squash signal to tell stages that they should 502 // squash. 503 toIEW->commitInfo[tid].squash = true; 504 505 // Send back the rob squashing signal so other stages know that 506 // the ROB is in the process of squashing. 507 toIEW->commitInfo[tid].robSquashing = true; 508 509 toIEW->commitInfo[tid].branchMispredict = false; 510 511 toIEW->commitInfo[tid].nextPC = PC[tid]; 512 toIEW->commitInfo[tid].nextNPC = nextPC[tid]; 513 toIEW->commitInfo[tid].nextMicroPC = nextMicroPC[tid]; 514} 515 516template <class Impl> 517void 518DefaultCommit<Impl>::squashFromTrap(unsigned tid) 519{ 520 squashAll(tid); 521 522 DPRINTF(Commit, "Squashing from trap, restarting at PC %#x\n", PC[tid]); 523 524 thread[tid]->trapPending = false; 525 thread[tid]->inSyscall = false; 526 trapInFlight[tid] = false; 527 528 trapSquash[tid] = false; 529 530 commitStatus[tid] = ROBSquashing; 531 cpu->activityThisCycle(); 532} 533 534template <class Impl> 535void 536DefaultCommit<Impl>::squashFromTC(unsigned tid) 537{ 538 squashAll(tid); 539 540 DPRINTF(Commit, "Squashing from TC, restarting at PC %#x\n", PC[tid]); 541 542 thread[tid]->inSyscall = false; 543 assert(!thread[tid]->trapPending); 544 545 commitStatus[tid] = ROBSquashing; 546 cpu->activityThisCycle(); 547 548 tcSquash[tid] = false; 549} 550 551template <class Impl> 552void 553DefaultCommit<Impl>::tick() 554{ 555 wroteToTimeBuffer = false; 556 _nextStatus = Inactive; 557 558 if (drainPending && rob->isEmpty() && !iewStage->hasStoresToWB()) { 559 cpu->signalDrained(); 560 drainPending = false; 561 return; 562 } 563 564 if (activeThreads->empty()) 565 return; 566 567 std::list<unsigned>::iterator threads = activeThreads->begin(); 568 std::list<unsigned>::iterator end = activeThreads->end(); 569 570 // Check if any of the threads are done squashing. Change the 571 // status if they are done. 572 while (threads != end) { 573 unsigned tid = *threads++; 574 575 // Clear the bit saying if the thread has committed stores 576 // this cycle. 577 committedStores[tid] = false; 578 579 if (commitStatus[tid] == ROBSquashing) { 580 581 if (rob->isDoneSquashing(tid)) { 582 commitStatus[tid] = Running; 583 } else { 584 DPRINTF(Commit,"[tid:%u]: Still Squashing, cannot commit any" 585 " insts this cycle.\n", tid); 586 rob->doSquash(tid); 587 toIEW->commitInfo[tid].robSquashing = true; 588 wroteToTimeBuffer = true; 589 } 590 } 591 } 592 593 commit(); 594 595 markCompletedInsts(); 596 597 threads = activeThreads->begin(); 598 599 while (threads != end) { 600 unsigned tid = *threads++; 601 602 if (!rob->isEmpty(tid) && rob->readHeadInst(tid)->readyToCommit()) { 603 // The ROB has more instructions it can commit. Its next status 604 // will be active. 605 _nextStatus = Active; 606 607 DynInstPtr inst = rob->readHeadInst(tid); 608 609 DPRINTF(Commit,"[tid:%i]: Instruction [sn:%lli] PC %#x is head of" 610 " ROB and ready to commit\n", 611 tid, inst->seqNum, inst->readPC()); 612 613 } else if (!rob->isEmpty(tid)) { 614 DynInstPtr inst = rob->readHeadInst(tid); 615 616 DPRINTF(Commit,"[tid:%i]: Can't commit, Instruction [sn:%lli] PC " 617 "%#x is head of ROB and not ready\n", 618 tid, inst->seqNum, inst->readPC()); 619 } 620 621 DPRINTF(Commit, "[tid:%i]: ROB has %d insts & %d free entries.\n", 622 tid, rob->countInsts(tid), rob->numFreeEntries(tid)); 623 } 624 625 626 if (wroteToTimeBuffer) { 627 DPRINTF(Activity, "Activity This Cycle.\n"); 628 cpu->activityThisCycle(); 629 } 630 631 updateStatus(); 632} 633 634#if FULL_SYSTEM 635template <class Impl> 636void 637DefaultCommit<Impl>::handleInterrupt() 638{ 639 if (interrupt != NoFault) { 640 // Wait until the ROB is empty and all stores have drained in 641 // order to enter the interrupt. 642 if (rob->isEmpty() && !iewStage->hasStoresToWB()) { 643 // Squash or record that I need to squash this cycle if 644 // an interrupt needed to be handled. 645 DPRINTF(Commit, "Interrupt detected.\n"); 646 647 // Clear the interrupt now that it's going to be handled 648 toIEW->commitInfo[0].clearInterrupt = true; 649 650 assert(!thread[0]->inSyscall); 651 thread[0]->inSyscall = true; 652 653 // CPU will handle interrupt. 654 cpu->processInterrupts(interrupt); 655 656 thread[0]->inSyscall = false; 657 658 commitStatus[0] = TrapPending; 659 660 // Generate trap squash event. 661 generateTrapEvent(0); 662 663 interrupt = NoFault; 664 } else { 665 DPRINTF(Commit, "Interrupt pending, waiting for ROB to empty.\n"); 666 } 667 } else if (commitStatus[0] != TrapPending && 668 cpu->checkInterrupts(cpu->tcBase(0)) && 669 !trapSquash[0] && 670 !tcSquash[0]) { 671 // Process interrupts if interrupts are enabled, not in PAL 672 // mode, and no other traps or external squashes are currently 673 // pending. 674 // @todo: Allow other threads to handle interrupts. 675 676 // Get any interrupt that happened 677 interrupt = cpu->getInterrupts(); 678 679 if (interrupt != NoFault) { 680 // Tell fetch that there is an interrupt pending. This 681 // will make fetch wait until it sees a non PAL-mode PC, 682 // at which point it stops fetching instructions. 683 toIEW->commitInfo[0].interruptPending = true; 684 } 685 } 686} 687#endif // FULL_SYSTEM 688 689template <class Impl> 690void 691DefaultCommit<Impl>::commit() 692{ 693 694#if FULL_SYSTEM 695 // Check for any interrupt, and start processing it. Or if we 696 // have an outstanding interrupt and are at a point when it is 697 // valid to take an interrupt, process it. 698 if (cpu->checkInterrupts(cpu->tcBase(0))) { 699 handleInterrupt(); 700 } 701#endif // FULL_SYSTEM 702 703 //////////////////////////////////// 704 // Check for any possible squashes, handle them first 705 //////////////////////////////////// 706 std::list<unsigned>::iterator threads = activeThreads->begin(); 707 std::list<unsigned>::iterator end = activeThreads->end(); 708 709 while (threads != end) { 710 unsigned tid = *threads++; 711 712 // Not sure which one takes priority. I think if we have 713 // both, that's a bad sign. 714 if (trapSquash[tid] == true) { 715 assert(!tcSquash[tid]); 716 squashFromTrap(tid); 717 } else if (tcSquash[tid] == true) { 718 assert(commitStatus[tid] != TrapPending); 719 squashFromTC(tid); 720 } 721 722 // Squashed sequence number must be older than youngest valid 723 // instruction in the ROB. This prevents squashes from younger 724 // instructions overriding squashes from older instructions. 725 if (fromIEW->squash[tid] && 726 commitStatus[tid] != TrapPending && 727 fromIEW->squashedSeqNum[tid] <= youngestSeqNum[tid]) { 728 729 DPRINTF(Commit, "[tid:%i]: Squashing due to PC %#x [sn:%i]\n", 730 tid, 731 fromIEW->mispredPC[tid], 732 fromIEW->squashedSeqNum[tid]); 733 734 DPRINTF(Commit, "[tid:%i]: Redirecting to PC %#x\n", 735 tid, 736 fromIEW->nextPC[tid]); 737 738 commitStatus[tid] = ROBSquashing; 739 740 // If we want to include the squashing instruction in the squash, 741 // then use one older sequence number. 742 InstSeqNum squashed_inst = fromIEW->squashedSeqNum[tid]; 743 744 if (fromIEW->includeSquashInst[tid] == true) { 745 squashed_inst--; 746 } 747 748 // All younger instructions will be squashed. Set the sequence 749 // number as the youngest instruction in the ROB. 750 youngestSeqNum[tid] = squashed_inst; 751 752 rob->squash(squashed_inst, tid); 753 changedROBNumEntries[tid] = true; 754 755 toIEW->commitInfo[tid].doneSeqNum = squashed_inst; 756 757 toIEW->commitInfo[tid].squash = true; 758 759 // Send back the rob squashing signal so other stages know that 760 // the ROB is in the process of squashing. 761 toIEW->commitInfo[tid].robSquashing = true; 762 763 toIEW->commitInfo[tid].branchMispredict = 764 fromIEW->branchMispredict[tid]; 765 766 toIEW->commitInfo[tid].branchTaken = 767 fromIEW->branchTaken[tid]; 768 769 toIEW->commitInfo[tid].nextPC = fromIEW->nextPC[tid]; 770 toIEW->commitInfo[tid].nextNPC = fromIEW->nextNPC[tid]; 771 toIEW->commitInfo[tid].nextMicroPC = fromIEW->nextMicroPC[tid]; 772 773 toIEW->commitInfo[tid].mispredPC = fromIEW->mispredPC[tid]; 774 775 if (toIEW->commitInfo[tid].branchMispredict) { 776 ++branchMispredicts; 777 } 778 } 779 780 } 781 782 setNextStatus(); 783 784 if (squashCounter != numThreads) { 785 // If we're not currently squashing, then get instructions. 786 getInsts(); 787 788 // Try to commit any instructions. 789 commitInsts(); 790 } 791 792 //Check for any activity 793 threads = activeThreads->begin(); 794 795 while (threads != end) { 796 unsigned tid = *threads++; 797 798 if (changedROBNumEntries[tid]) { 799 toIEW->commitInfo[tid].usedROB = true; 800 toIEW->commitInfo[tid].freeROBEntries = rob->numFreeEntries(tid); 801 802 wroteToTimeBuffer = true; 803 changedROBNumEntries[tid] = false; 804 if (rob->isEmpty(tid)) 805 checkEmptyROB[tid] = true; 806 } 807 808 // ROB is only considered "empty" for previous stages if: a) 809 // ROB is empty, b) there are no outstanding stores, c) IEW 810 // stage has received any information regarding stores that 811 // committed. 812 // c) is checked by making sure to not consider the ROB empty 813 // on the same cycle as when stores have been committed. 814 // @todo: Make this handle multi-cycle communication between 815 // commit and IEW. 816 if (checkEmptyROB[tid] && rob->isEmpty(tid) && 817 !iewStage->hasStoresToWB(tid) && !committedStores[tid]) { 818 checkEmptyROB[tid] = false; 819 toIEW->commitInfo[tid].usedROB = true; 820 toIEW->commitInfo[tid].emptyROB = true; 821 toIEW->commitInfo[tid].freeROBEntries = rob->numFreeEntries(tid); 822 wroteToTimeBuffer = true; 823 } 824 825 } 826} 827 828template <class Impl> 829void 830DefaultCommit<Impl>::commitInsts() 831{ 832 //////////////////////////////////// 833 // Handle commit 834 // Note that commit will be handled prior to putting new 835 // instructions in the ROB so that the ROB only tries to commit 836 // instructions it has in this current cycle, and not instructions 837 // it is writing in during this cycle. Can't commit and squash 838 // things at the same time... 839 //////////////////////////////////// 840 841 DPRINTF(Commit, "Trying to commit instructions in the ROB.\n"); 842 843 unsigned num_committed = 0; 844 845 DynInstPtr head_inst; 846 847 // Commit as many instructions as possible until the commit bandwidth 848 // limit is reached, or it becomes impossible to commit any more. 849 while (num_committed < commitWidth) { 850 int commit_thread = getCommittingThread(); 851 852 if (commit_thread == -1 || !rob->isHeadReady(commit_thread)) 853 break; 854 855 head_inst = rob->readHeadInst(commit_thread); 856 857 int tid = head_inst->threadNumber; 858 859 assert(tid == commit_thread); 860 861 DPRINTF(Commit, "Trying to commit head instruction, [sn:%i] [tid:%i]\n", 862 head_inst->seqNum, tid); 863 864 // If the head instruction is squashed, it is ready to retire 865 // (be removed from the ROB) at any time. 866 if (head_inst->isSquashed()) { 867 868 DPRINTF(Commit, "Retiring squashed instruction from " 869 "ROB.\n"); 870 871 rob->retireHead(commit_thread); 872 873 ++commitSquashedInsts; 874 875 // Record that the number of ROB entries has changed. 876 changedROBNumEntries[tid] = true; 877 } else { 878 PC[tid] = head_inst->readPC(); 879 nextPC[tid] = head_inst->readNextPC(); 880 nextNPC[tid] = head_inst->readNextNPC(); 881 nextMicroPC[tid] = head_inst->readNextMicroPC(); 882 883 // Increment the total number of non-speculative instructions 884 // executed. 885 // Hack for now: it really shouldn't happen until after the 886 // commit is deemed to be successful, but this count is needed 887 // for syscalls. 888 thread[tid]->funcExeInst++; 889 890 // Try to commit the head instruction. 891 bool commit_success = commitHead(head_inst, num_committed); 892 893 if (commit_success) { 894 ++num_committed; 895 896 changedROBNumEntries[tid] = true; 897 898 // Set the doneSeqNum to the youngest committed instruction. 899 toIEW->commitInfo[tid].doneSeqNum = head_inst->seqNum; 900 901 ++commitCommittedInsts; 902 903 // To match the old model, don't count nops and instruction 904 // prefetches towards the total commit count. 905 if (!head_inst->isNop() && !head_inst->isInstPrefetch()) { 906 cpu->instDone(tid); 907 } 908 909 PC[tid] = nextPC[tid]; 910 nextPC[tid] = nextNPC[tid]; 911 nextNPC[tid] = nextNPC[tid] + sizeof(TheISA::MachInst); 912 microPC[tid] = nextMicroPC[tid]; 913 nextMicroPC[tid] = microPC[tid] + 1; 914 915 int count = 0; 916 Addr oldpc; 917 // Debug statement. Checks to make sure we're not 918 // currently updating state while handling PC events. 919 assert(!thread[tid]->inSyscall && !thread[tid]->trapPending); 920 do { 921 oldpc = PC[tid]; 922 cpu->system->pcEventQueue.service(thread[tid]->getTC()); 923 count++; 924 } while (oldpc != PC[tid]); 925 if (count > 1) { 926 DPRINTF(Commit, 927 "PC skip function event, stopping commit\n"); 928 break; 929 } 930 } else { 931 DPRINTF(Commit, "Unable to commit head instruction PC:%#x " 932 "[tid:%i] [sn:%i].\n", 933 head_inst->readPC(), tid ,head_inst->seqNum); 934 break; 935 } 936 } 937 } 938 939 DPRINTF(CommitRate, "%i\n", num_committed); 940 numCommittedDist.sample(num_committed); 941 942 if (num_committed == commitWidth) { 943 commitEligibleSamples++; 944 } 945} 946 947template <class Impl> 948bool 949DefaultCommit<Impl>::commitHead(DynInstPtr &head_inst, unsigned inst_num) 950{ 951 assert(head_inst); 952 953 int tid = head_inst->threadNumber; 954 955 // If the instruction is not executed yet, then it will need extra 956 // handling. Signal backwards that it should be executed. 957 if (!head_inst->isExecuted()) { 958 // Keep this number correct. We have not yet actually executed 959 // and committed this instruction. 960 thread[tid]->funcExeInst--; 961 962 if (head_inst->isNonSpeculative() || 963 head_inst->isStoreConditional() || 964 head_inst->isMemBarrier() || 965 head_inst->isWriteBarrier()) { 966 967 DPRINTF(Commit, "Encountered a barrier or non-speculative " 968 "instruction [sn:%lli] at the head of the ROB, PC %#x.\n", 969 head_inst->seqNum, head_inst->readPC()); 970 971 if (inst_num > 0 || iewStage->hasStoresToWB(tid)) { 972 DPRINTF(Commit, "Waiting for all stores to writeback.\n"); 973 return false; 974 } 975 976 toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum; 977 978 // Change the instruction so it won't try to commit again until 979 // it is executed. 980 head_inst->clearCanCommit(); 981 982 ++commitNonSpecStalls; 983 984 return false; 985 } else if (head_inst->isLoad()) { 986 if (inst_num > 0 || iewStage->hasStoresToWB(tid)) { 987 DPRINTF(Commit, "Waiting for all stores to writeback.\n"); 988 return false; 989 } 990 991 assert(head_inst->uncacheable()); 992 DPRINTF(Commit, "[sn:%lli]: Uncached load, PC %#x.\n", 993 head_inst->seqNum, head_inst->readPC()); 994 995 // Send back the non-speculative instruction's sequence 996 // number. Tell the lsq to re-execute the load. 997 toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum; 998 toIEW->commitInfo[tid].uncached = true; 999 toIEW->commitInfo[tid].uncachedLoad = head_inst; 1000 1001 head_inst->clearCanCommit(); 1002 1003 return false; 1004 } else { 1005 panic("Trying to commit un-executed instruction " 1006 "of unknown type!\n"); 1007 } 1008 } 1009 1010 if (head_inst->isThreadSync()) { 1011 // Not handled for now. 1012 panic("Thread sync instructions are not handled yet.\n"); 1013 } 1014 1015 // Check if the instruction caused a fault. If so, trap. 1016 Fault inst_fault = head_inst->getFault(); 1017 1018 // Stores mark themselves as completed. 1019 if (!head_inst->isStore() && inst_fault == NoFault) { 1020 head_inst->setCompleted(); 1021 } 1022 1023#if USE_CHECKER 1024 // Use checker prior to updating anything due to traps or PC 1025 // based events. 1026 if (cpu->checker) { 1027 cpu->checker->verify(head_inst); 1028 } 1029#endif 1030 1031 // DTB will sometimes need the machine instruction for when 1032 // faults happen. So we will set it here, prior to the DTB 1033 // possibly needing it for its fault. 1034 thread[tid]->setInst( 1035 static_cast<TheISA::MachInst>(head_inst->staticInst->machInst)); 1036 1037 if (inst_fault != NoFault) { 1038 DPRINTF(Commit, "Inst [sn:%lli] PC %#x has a fault\n", 1039 head_inst->seqNum, head_inst->readPC()); 1040 1041 if (iewStage->hasStoresToWB(tid) || inst_num > 0) { 1042 DPRINTF(Commit, "Stores outstanding, fault must wait.\n"); 1043 return false; 1044 } 1045 1046 head_inst->setCompleted(); 1047 1048#if USE_CHECKER 1049 if (cpu->checker && head_inst->isStore()) { 1050 cpu->checker->verify(head_inst); 1051 } 1052#endif 1053 1054 assert(!thread[tid]->inSyscall); 1055 1056 // Mark that we're in state update mode so that the trap's 1057 // execution doesn't generate extra squashes. 1058 thread[tid]->inSyscall = true; 1059 1060 // Execute the trap. Although it's slightly unrealistic in 1061 // terms of timing (as it doesn't wait for the full timing of 1062 // the trap event to complete before updating state), it's 1063 // needed to update the state as soon as possible. This 1064 // prevents external agents from changing any specific state 1065 // that the trap need. 1066 cpu->trap(inst_fault, tid); 1067 1068 // Exit state update mode to avoid accidental updating. 1069 thread[tid]->inSyscall = false; 1070 1071 commitStatus[tid] = TrapPending; 1072 1073 if (head_inst->traceData) { 1074 head_inst->traceData->setFetchSeq(head_inst->seqNum); 1075 head_inst->traceData->setCPSeq(thread[tid]->numInst); 1076 head_inst->traceData->dump(); 1077 delete head_inst->traceData; 1078 head_inst->traceData = NULL; 1079 } 1080 1081 // Generate trap squash event. 1082 generateTrapEvent(tid); 1083// warn("%lli fault (%d) handled @ PC %08p", curTick, inst_fault->name(), head_inst->readPC()); 1084 return false; 1085 } 1086 1087 updateComInstStats(head_inst); 1088 1089#if FULL_SYSTEM 1090 if (thread[tid]->profile) { 1091// bool usermode = TheISA::inUserMode(thread[tid]->getTC()); 1092// thread[tid]->profilePC = usermode ? 1 : head_inst->readPC(); 1093 thread[tid]->profilePC = head_inst->readPC(); 1094 ProfileNode *node = thread[tid]->profile->consume(thread[tid]->getTC(), 1095 head_inst->staticInst); 1096 1097 if (node) 1098 thread[tid]->profileNode = node; 1099 } 1100#endif 1101 1102 if (head_inst->traceData) { 1103 head_inst->traceData->setFetchSeq(head_inst->seqNum); 1104 head_inst->traceData->setCPSeq(thread[tid]->numInst); 1105 head_inst->traceData->dump(); 1106 delete head_inst->traceData; 1107 head_inst->traceData = NULL; 1108 } 1109 1110 // Update the commit rename map 1111 for (int i = 0; i < head_inst->numDestRegs(); i++) { 1112 renameMap[tid]->setEntry(head_inst->flattenedDestRegIdx(i), 1113 head_inst->renamedDestRegIdx(i)); 1114 } 1115 1116 if (head_inst->isCopy()) 1117 panic("Should not commit any copy instructions!"); 1118 1119 // Finally clear the head ROB entry. 1120 rob->retireHead(tid); 1121 1122 // If this was a store, record it for this cycle. 1123 if (head_inst->isStore()) 1124 committedStores[tid] = true; 1125 1126 // Return true to indicate that we have committed an instruction. 1127 return true; 1128} 1129 1130template <class Impl> 1131void 1132DefaultCommit<Impl>::getInsts() 1133{ 1134 DPRINTF(Commit, "Getting instructions from Rename stage.\n"); 1135 1136 // Read any renamed instructions and place them into the ROB. 1137 int insts_to_process = std::min((int)renameWidth, fromRename->size); 1138 1139 for (int inst_num = 0; inst_num < insts_to_process; ++inst_num) { 1140 DynInstPtr inst; 1141 1142 inst = fromRename->insts[inst_num]; 1143 int tid = inst->threadNumber; 1144 1145 if (!inst->isSquashed() && 1146 commitStatus[tid] != ROBSquashing && 1147 commitStatus[tid] != TrapPending) { 1148 changedROBNumEntries[tid] = true; 1149 1150 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ROB.\n", 1151 inst->readPC(), inst->seqNum, tid); 1152 1153 rob->insertInst(inst); 1154 1155 assert(rob->getThreadEntries(tid) <= rob->getMaxEntries(tid)); 1156 1157 youngestSeqNum[tid] = inst->seqNum; 1158 } else { 1159 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was " 1160 "squashed, skipping.\n", 1161 inst->readPC(), inst->seqNum, tid); 1162 } 1163 } 1164} 1165 1166template <class Impl> 1167void 1168DefaultCommit<Impl>::skidInsert() 1169{ 1170 DPRINTF(Commit, "Attempting to any instructions from rename into " 1171 "skidBuffer.\n"); 1172 1173 for (int inst_num = 0; inst_num < fromRename->size; ++inst_num) { 1174 DynInstPtr inst = fromRename->insts[inst_num]; 1175 1176 if (!inst->isSquashed()) { 1177 DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ", 1178 "skidBuffer.\n", inst->readPC(), inst->seqNum, 1179 inst->threadNumber); 1180 skidBuffer.push(inst); 1181 } else { 1182 DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was " 1183 "squashed, skipping.\n", 1184 inst->readPC(), inst->seqNum, inst->threadNumber); 1185 } 1186 } 1187} 1188 1189template <class Impl> 1190void 1191DefaultCommit<Impl>::markCompletedInsts() 1192{ 1193 // Grab completed insts out of the IEW instruction queue, and mark 1194 // instructions completed within the ROB. 1195 for (int inst_num = 0; 1196 inst_num < fromIEW->size && fromIEW->insts[inst_num]; 1197 ++inst_num) 1198 { 1199 if (!fromIEW->insts[inst_num]->isSquashed()) { 1200 DPRINTF(Commit, "[tid:%i]: Marking PC %#x, [sn:%lli] ready " 1201 "within ROB.\n", 1202 fromIEW->insts[inst_num]->threadNumber, 1203 fromIEW->insts[inst_num]->readPC(), 1204 fromIEW->insts[inst_num]->seqNum); 1205 1206 // Mark the instruction as ready to commit. 1207 fromIEW->insts[inst_num]->setCanCommit(); 1208 } 1209 } 1210} 1211 1212template <class Impl> 1213bool 1214DefaultCommit<Impl>::robDoneSquashing() 1215{ 1216 std::list<unsigned>::iterator threads = activeThreads->begin(); 1217 std::list<unsigned>::iterator end = activeThreads->end(); 1218 1219 while (threads != end) { 1220 unsigned tid = *threads++; 1221 1222 if (!rob->isDoneSquashing(tid)) 1223 return false; 1224 } 1225 1226 return true; 1227} 1228 1229template <class Impl> 1230void 1231DefaultCommit<Impl>::updateComInstStats(DynInstPtr &inst) 1232{ 1233 unsigned thread = inst->threadNumber; 1234 1235 // 1236 // Pick off the software prefetches 1237 // 1238#ifdef TARGET_ALPHA 1239 if (inst->isDataPrefetch()) { 1240 statComSwp[thread]++; 1241 } else { 1242 statComInst[thread]++; 1243 } 1244#else 1245 statComInst[thread]++; 1246#endif 1247 1248 // 1249 // Control Instructions 1250 // 1251 if (inst->isControl()) 1252 statComBranches[thread]++; 1253 1254 // 1255 // Memory references 1256 // 1257 if (inst->isMemRef()) { 1258 statComRefs[thread]++; 1259 1260 if (inst->isLoad()) { 1261 statComLoads[thread]++; 1262 } 1263 } 1264 1265 if (inst->isMemBarrier()) { 1266 statComMembars[thread]++; 1267 } 1268} 1269 1270//////////////////////////////////////// 1271// // 1272// SMT COMMIT POLICY MAINTAINED HERE // 1273// // 1274//////////////////////////////////////// 1275template <class Impl> 1276int 1277DefaultCommit<Impl>::getCommittingThread() 1278{ 1279 if (numThreads > 1) { 1280 switch (commitPolicy) { 1281 1282 case Aggressive: 1283 //If Policy is Aggressive, commit will call 1284 //this function multiple times per 1285 //cycle 1286 return oldestReady(); 1287 1288 case RoundRobin: 1289 return roundRobin(); 1290 1291 case OldestReady: 1292 return oldestReady(); 1293 1294 default: 1295 return -1; 1296 } 1297 } else { 1298 assert(!activeThreads->empty()); 1299 int tid = activeThreads->front(); 1300 1301 if (commitStatus[tid] == Running || 1302 commitStatus[tid] == Idle || 1303 commitStatus[tid] == FetchTrapPending) { 1304 return tid; 1305 } else { 1306 return -1; 1307 } 1308 } 1309} 1310 1311template<class Impl> 1312int 1313DefaultCommit<Impl>::roundRobin() 1314{ 1315 std::list<unsigned>::iterator pri_iter = priority_list.begin(); 1316 std::list<unsigned>::iterator end = priority_list.end(); 1317 1318 while (pri_iter != end) { 1319 unsigned tid = *pri_iter; 1320 1321 if (commitStatus[tid] == Running || 1322 commitStatus[tid] == Idle || 1323 commitStatus[tid] == FetchTrapPending) { 1324 1325 if (rob->isHeadReady(tid)) { 1326 priority_list.erase(pri_iter); 1327 priority_list.push_back(tid); 1328 1329 return tid; 1330 } 1331 } 1332 1333 pri_iter++; 1334 } 1335 1336 return -1; 1337} 1338 1339template<class Impl> 1340int 1341DefaultCommit<Impl>::oldestReady() 1342{ 1343 unsigned oldest = 0; 1344 bool first = true; 1345 1346 std::list<unsigned>::iterator threads = activeThreads->begin(); 1347 std::list<unsigned>::iterator end = activeThreads->end(); 1348 1349 while (threads != end) { 1350 unsigned tid = *threads++; 1351 1352 if (!rob->isEmpty(tid) && 1353 (commitStatus[tid] == Running || 1354 commitStatus[tid] == Idle || 1355 commitStatus[tid] == FetchTrapPending)) { 1356 1357 if (rob->isHeadReady(tid)) { 1358 1359 DynInstPtr head_inst = rob->readHeadInst(tid); 1360 1361 if (first) { 1362 oldest = tid; 1363 first = false; 1364 } else if (head_inst->seqNum < oldest) { 1365 oldest = tid; 1366 } 1367 } 1368 } 1369 } 1370 1371 if (!first) { 1372 return oldest; 1373 } else { 1374 return -1; 1375 } 1376} 1377