rename_impl.hh revision 9919
1/* 2 * Copyright (c) 2010-2012 ARM Limited 3 * Copyright (c) 2013 Advanced Micro Devices, Inc. 4 * All rights reserved. 5 * 6 * The license below extends only to copyright in the software and shall 7 * not be construed as granting a license to any other intellectual 8 * property including but not limited to intellectual property relating 9 * to a hardware implementation of the functionality of the software 10 * licensed hereunder. You may use the software subject to the license 11 * terms below provided that you ensure that this notice is replicated 12 * unmodified and in its entirety in all distributions of the software, 13 * modified or unmodified, in source code or in binary form. 14 * 15 * Copyright (c) 2004-2006 The Regents of The University of Michigan 16 * All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions are 20 * met: redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer; 22 * redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution; 25 * neither the name of the copyright holders nor the names of its 26 * contributors may be used to endorse or promote products derived from 27 * this software without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 * 41 * Authors: Kevin Lim 42 * Korey Sewell 43 */ 44 45#include <list> 46 47#include "arch/isa_traits.hh" 48#include "arch/registers.hh" 49#include "config/the_isa.hh" 50#include "cpu/o3/rename.hh" 51#include "cpu/reg_class.hh" 52#include "debug/Activity.hh" 53#include "debug/Rename.hh" 54#include "debug/O3PipeView.hh" 55#include "params/DerivO3CPU.hh" 56 57using namespace std; 58 59template <class Impl> 60DefaultRename<Impl>::DefaultRename(O3CPU *_cpu, DerivO3CPUParams *params) 61 : cpu(_cpu), 62 iewToRenameDelay(params->iewToRenameDelay), 63 decodeToRenameDelay(params->decodeToRenameDelay), 64 commitToRenameDelay(params->commitToRenameDelay), 65 renameWidth(params->renameWidth), 66 commitWidth(params->commitWidth), 67 numThreads(params->numThreads), 68 maxPhysicalRegs(params->numPhysIntRegs + params->numPhysFloatRegs) 69{ 70 // @todo: Make into a parameter. 71 skidBufferMax = (2 * (decodeToRenameDelay * params->decodeWidth)) + renameWidth; 72} 73 74template <class Impl> 75std::string 76DefaultRename<Impl>::name() const 77{ 78 return cpu->name() + ".rename"; 79} 80 81template <class Impl> 82void 83DefaultRename<Impl>::regStats() 84{ 85 renameSquashCycles 86 .name(name() + ".SquashCycles") 87 .desc("Number of cycles rename is squashing") 88 .prereq(renameSquashCycles); 89 renameIdleCycles 90 .name(name() + ".IdleCycles") 91 .desc("Number of cycles rename is idle") 92 .prereq(renameIdleCycles); 93 renameBlockCycles 94 .name(name() + ".BlockCycles") 95 .desc("Number of cycles rename is blocking") 96 .prereq(renameBlockCycles); 97 renameSerializeStallCycles 98 .name(name() + ".serializeStallCycles") 99 .desc("count of cycles rename stalled for serializing inst") 100 .flags(Stats::total); 101 renameRunCycles 102 .name(name() + ".RunCycles") 103 .desc("Number of cycles rename is running") 104 .prereq(renameIdleCycles); 105 renameUnblockCycles 106 .name(name() + ".UnblockCycles") 107 .desc("Number of cycles rename is unblocking") 108 .prereq(renameUnblockCycles); 109 renameRenamedInsts 110 .name(name() + ".RenamedInsts") 111 .desc("Number of instructions processed by rename") 112 .prereq(renameRenamedInsts); 113 renameSquashedInsts 114 .name(name() + ".SquashedInsts") 115 .desc("Number of squashed instructions processed by rename") 116 .prereq(renameSquashedInsts); 117 renameROBFullEvents 118 .name(name() + ".ROBFullEvents") 119 .desc("Number of times rename has blocked due to ROB full") 120 .prereq(renameROBFullEvents); 121 renameIQFullEvents 122 .name(name() + ".IQFullEvents") 123 .desc("Number of times rename has blocked due to IQ full") 124 .prereq(renameIQFullEvents); 125 renameLSQFullEvents 126 .name(name() + ".LSQFullEvents") 127 .desc("Number of times rename has blocked due to LSQ full") 128 .prereq(renameLSQFullEvents); 129 renameFullRegistersEvents 130 .name(name() + ".FullRegisterEvents") 131 .desc("Number of times there has been no free registers") 132 .prereq(renameFullRegistersEvents); 133 renameRenamedOperands 134 .name(name() + ".RenamedOperands") 135 .desc("Number of destination operands rename has renamed") 136 .prereq(renameRenamedOperands); 137 renameRenameLookups 138 .name(name() + ".RenameLookups") 139 .desc("Number of register rename lookups that rename has made") 140 .prereq(renameRenameLookups); 141 renameCommittedMaps 142 .name(name() + ".CommittedMaps") 143 .desc("Number of HB maps that are committed") 144 .prereq(renameCommittedMaps); 145 renameUndoneMaps 146 .name(name() + ".UndoneMaps") 147 .desc("Number of HB maps that are undone due to squashing") 148 .prereq(renameUndoneMaps); 149 renamedSerializing 150 .name(name() + ".serializingInsts") 151 .desc("count of serializing insts renamed") 152 .flags(Stats::total) 153 ; 154 renamedTempSerializing 155 .name(name() + ".tempSerializingInsts") 156 .desc("count of temporary serializing insts renamed") 157 .flags(Stats::total) 158 ; 159 renameSkidInsts 160 .name(name() + ".skidInsts") 161 .desc("count of insts added to the skid buffer") 162 .flags(Stats::total) 163 ; 164 intRenameLookups 165 .name(name() + ".int_rename_lookups") 166 .desc("Number of integer rename lookups") 167 .prereq(intRenameLookups); 168 fpRenameLookups 169 .name(name() + ".fp_rename_lookups") 170 .desc("Number of floating rename lookups") 171 .prereq(fpRenameLookups); 172} 173 174template <class Impl> 175void 176DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) 177{ 178 timeBuffer = tb_ptr; 179 180 // Setup wire to read information from time buffer, from IEW stage. 181 fromIEW = timeBuffer->getWire(-iewToRenameDelay); 182 183 // Setup wire to read infromation from time buffer, from commit stage. 184 fromCommit = timeBuffer->getWire(-commitToRenameDelay); 185 186 // Setup wire to write information to previous stages. 187 toDecode = timeBuffer->getWire(0); 188} 189 190template <class Impl> 191void 192DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) 193{ 194 renameQueue = rq_ptr; 195 196 // Setup wire to write information to future stages. 197 toIEW = renameQueue->getWire(0); 198} 199 200template <class Impl> 201void 202DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr) 203{ 204 decodeQueue = dq_ptr; 205 206 // Setup wire to get information from decode. 207 fromDecode = decodeQueue->getWire(-decodeToRenameDelay); 208} 209 210template <class Impl> 211void 212DefaultRename<Impl>::startupStage() 213{ 214 resetStage(); 215} 216 217template <class Impl> 218void 219DefaultRename<Impl>::resetStage() 220{ 221 _status = Inactive; 222 223 resumeSerialize = false; 224 resumeUnblocking = false; 225 226 // Grab the number of free entries directly from the stages. 227 for (ThreadID tid = 0; tid < numThreads; tid++) { 228 renameStatus[tid] = Idle; 229 230 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid); 231 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid); 232 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid); 233 emptyROB[tid] = true; 234 235 stalls[tid].iew = false; 236 stalls[tid].commit = false; 237 serializeInst[tid] = NULL; 238 239 instsInProgress[tid] = 0; 240 241 serializeOnNextInst[tid] = false; 242 } 243} 244 245template<class Impl> 246void 247DefaultRename<Impl>::setActiveThreads(list<ThreadID> *at_ptr) 248{ 249 activeThreads = at_ptr; 250} 251 252 253template <class Impl> 254void 255DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[]) 256{ 257 for (ThreadID tid = 0; tid < numThreads; tid++) 258 renameMap[tid] = &rm_ptr[tid]; 259} 260 261template <class Impl> 262void 263DefaultRename<Impl>::setFreeList(FreeList *fl_ptr) 264{ 265 freeList = fl_ptr; 266} 267 268template<class Impl> 269void 270DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard) 271{ 272 scoreboard = _scoreboard; 273} 274 275template <class Impl> 276bool 277DefaultRename<Impl>::isDrained() const 278{ 279 for (ThreadID tid = 0; tid < numThreads; tid++) { 280 if (instsInProgress[tid] != 0 || 281 !historyBuffer[tid].empty() || 282 !skidBuffer[tid].empty() || 283 !insts[tid].empty()) 284 return false; 285 } 286 return true; 287} 288 289template <class Impl> 290void 291DefaultRename<Impl>::takeOverFrom() 292{ 293 resetStage(); 294} 295 296template <class Impl> 297void 298DefaultRename<Impl>::drainSanityCheck() const 299{ 300 for (ThreadID tid = 0; tid < numThreads; tid++) { 301 assert(historyBuffer[tid].empty()); 302 assert(insts[tid].empty()); 303 assert(skidBuffer[tid].empty()); 304 assert(instsInProgress[tid] == 0); 305 } 306} 307 308template <class Impl> 309void 310DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, ThreadID tid) 311{ 312 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid); 313 314 // Clear the stall signal if rename was blocked or unblocking before. 315 // If it still needs to block, the blocking should happen the next 316 // cycle and there should be space to hold everything due to the squash. 317 if (renameStatus[tid] == Blocked || 318 renameStatus[tid] == Unblocking) { 319 toDecode->renameUnblock[tid] = 1; 320 321 resumeSerialize = false; 322 serializeInst[tid] = NULL; 323 } else if (renameStatus[tid] == SerializeStall) { 324 if (serializeInst[tid]->seqNum <= squash_seq_num) { 325 DPRINTF(Rename, "Rename will resume serializing after squash\n"); 326 resumeSerialize = true; 327 assert(serializeInst[tid]); 328 } else { 329 resumeSerialize = false; 330 toDecode->renameUnblock[tid] = 1; 331 332 serializeInst[tid] = NULL; 333 } 334 } 335 336 // Set the status to Squashing. 337 renameStatus[tid] = Squashing; 338 339 // Squash any instructions from decode. 340 unsigned squashCount = 0; 341 342 for (int i=0; i<fromDecode->size; i++) { 343 if (fromDecode->insts[i]->threadNumber == tid && 344 fromDecode->insts[i]->seqNum > squash_seq_num) { 345 fromDecode->insts[i]->setSquashed(); 346 wroteToTimeBuffer = true; 347 squashCount++; 348 } 349 350 } 351 352 // Clear the instruction list and skid buffer in case they have any 353 // insts in them. 354 insts[tid].clear(); 355 356 // Clear the skid buffer in case it has any data in it. 357 skidBuffer[tid].clear(); 358 359 doSquash(squash_seq_num, tid); 360} 361 362template <class Impl> 363void 364DefaultRename<Impl>::tick() 365{ 366 wroteToTimeBuffer = false; 367 368 blockThisCycle = false; 369 370 bool status_change = false; 371 372 toIEWIndex = 0; 373 374 sortInsts(); 375 376 list<ThreadID>::iterator threads = activeThreads->begin(); 377 list<ThreadID>::iterator end = activeThreads->end(); 378 379 // Check stall and squash signals. 380 while (threads != end) { 381 ThreadID tid = *threads++; 382 383 DPRINTF(Rename, "Processing [tid:%i]\n", tid); 384 385 status_change = checkSignalsAndUpdate(tid) || status_change; 386 387 rename(status_change, tid); 388 } 389 390 if (status_change) { 391 updateStatus(); 392 } 393 394 if (wroteToTimeBuffer) { 395 DPRINTF(Activity, "Activity this cycle.\n"); 396 cpu->activityThisCycle(); 397 } 398 399 threads = activeThreads->begin(); 400 401 while (threads != end) { 402 ThreadID tid = *threads++; 403 404 // If we committed this cycle then doneSeqNum will be > 0 405 if (fromCommit->commitInfo[tid].doneSeqNum != 0 && 406 !fromCommit->commitInfo[tid].squash && 407 renameStatus[tid] != Squashing) { 408 409 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum, 410 tid); 411 } 412 } 413 414 // @todo: make into updateProgress function 415 for (ThreadID tid = 0; tid < numThreads; tid++) { 416 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched; 417 418 assert(instsInProgress[tid] >=0); 419 } 420 421} 422 423template<class Impl> 424void 425DefaultRename<Impl>::rename(bool &status_change, ThreadID tid) 426{ 427 // If status is Running or idle, 428 // call renameInsts() 429 // If status is Unblocking, 430 // buffer any instructions coming from decode 431 // continue trying to empty skid buffer 432 // check if stall conditions have passed 433 434 if (renameStatus[tid] == Blocked) { 435 ++renameBlockCycles; 436 } else if (renameStatus[tid] == Squashing) { 437 ++renameSquashCycles; 438 } else if (renameStatus[tid] == SerializeStall) { 439 ++renameSerializeStallCycles; 440 // If we are currently in SerializeStall and resumeSerialize 441 // was set, then that means that we are resuming serializing 442 // this cycle. Tell the previous stages to block. 443 if (resumeSerialize) { 444 resumeSerialize = false; 445 block(tid); 446 toDecode->renameUnblock[tid] = false; 447 } 448 } else if (renameStatus[tid] == Unblocking) { 449 if (resumeUnblocking) { 450 block(tid); 451 resumeUnblocking = false; 452 toDecode->renameUnblock[tid] = false; 453 } 454 } 455 456 if (renameStatus[tid] == Running || 457 renameStatus[tid] == Idle) { 458 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run " 459 "stage.\n", tid); 460 461 renameInsts(tid); 462 } else if (renameStatus[tid] == Unblocking) { 463 renameInsts(tid); 464 465 if (validInsts()) { 466 // Add the current inputs to the skid buffer so they can be 467 // reprocessed when this stage unblocks. 468 skidInsert(tid); 469 } 470 471 // If we switched over to blocking, then there's a potential for 472 // an overall status change. 473 status_change = unblock(tid) || status_change || blockThisCycle; 474 } 475} 476 477template <class Impl> 478void 479DefaultRename<Impl>::renameInsts(ThreadID tid) 480{ 481 // Instructions can be either in the skid buffer or the queue of 482 // instructions coming from decode, depending on the status. 483 int insts_available = renameStatus[tid] == Unblocking ? 484 skidBuffer[tid].size() : insts[tid].size(); 485 486 // Check the decode queue to see if instructions are available. 487 // If there are no available instructions to rename, then do nothing. 488 if (insts_available == 0) { 489 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n", 490 tid); 491 // Should I change status to idle? 492 ++renameIdleCycles; 493 return; 494 } else if (renameStatus[tid] == Unblocking) { 495 ++renameUnblockCycles; 496 } else if (renameStatus[tid] == Running) { 497 ++renameRunCycles; 498 } 499 500 DynInstPtr inst; 501 502 // Will have to do a different calculation for the number of free 503 // entries. 504 int free_rob_entries = calcFreeROBEntries(tid); 505 int free_iq_entries = calcFreeIQEntries(tid); 506 int free_lsq_entries = calcFreeLSQEntries(tid); 507 int min_free_entries = free_rob_entries; 508 509 FullSource source = ROB; 510 511 if (free_iq_entries < min_free_entries) { 512 min_free_entries = free_iq_entries; 513 source = IQ; 514 } 515 516 if (free_lsq_entries < min_free_entries) { 517 min_free_entries = free_lsq_entries; 518 source = LSQ; 519 } 520 521 // Check if there's any space left. 522 if (min_free_entries <= 0) { 523 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ " 524 "entries.\n" 525 "ROB has %i free entries.\n" 526 "IQ has %i free entries.\n" 527 "LSQ has %i free entries.\n", 528 tid, 529 free_rob_entries, 530 free_iq_entries, 531 free_lsq_entries); 532 533 blockThisCycle = true; 534 535 block(tid); 536 537 incrFullStat(source); 538 539 return; 540 } else if (min_free_entries < insts_available) { 541 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle." 542 "%i insts available, but only %i insts can be " 543 "renamed due to ROB/IQ/LSQ limits.\n", 544 tid, insts_available, min_free_entries); 545 546 insts_available = min_free_entries; 547 548 blockThisCycle = true; 549 550 incrFullStat(source); 551 } 552 553 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ? 554 skidBuffer[tid] : insts[tid]; 555 556 DPRINTF(Rename, "[tid:%u]: %i available instructions to " 557 "send iew.\n", tid, insts_available); 558 559 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts " 560 "dispatched to IQ last cycle.\n", 561 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched); 562 563 // Handle serializing the next instruction if necessary. 564 if (serializeOnNextInst[tid]) { 565 if (emptyROB[tid] && instsInProgress[tid] == 0) { 566 // ROB already empty; no need to serialize. 567 serializeOnNextInst[tid] = false; 568 } else if (!insts_to_rename.empty()) { 569 insts_to_rename.front()->setSerializeBefore(); 570 } 571 } 572 573 int renamed_insts = 0; 574 575 while (insts_available > 0 && toIEWIndex < renameWidth) { 576 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid); 577 578 assert(!insts_to_rename.empty()); 579 580 inst = insts_to_rename.front(); 581 582 insts_to_rename.pop_front(); 583 584 if (renameStatus[tid] == Unblocking) { 585 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%s from rename " 586 "skidBuffer\n", tid, inst->seqNum, inst->pcState()); 587 } 588 589 if (inst->isSquashed()) { 590 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %s is " 591 "squashed, skipping.\n", tid, inst->seqNum, 592 inst->pcState()); 593 594 ++renameSquashedInsts; 595 596 // Decrement how many instructions are available. 597 --insts_available; 598 599 continue; 600 } 601 602 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with " 603 "PC %s.\n", tid, inst->seqNum, inst->pcState()); 604 605 // Check here to make sure there are enough destination registers 606 // to rename to. Otherwise block. 607 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) { 608 DPRINTF(Rename, "Blocking due to lack of free " 609 "physical registers to rename to.\n"); 610 blockThisCycle = true; 611 insts_to_rename.push_front(inst); 612 ++renameFullRegistersEvents; 613 614 break; 615 } 616 617 // Handle serializeAfter/serializeBefore instructions. 618 // serializeAfter marks the next instruction as serializeBefore. 619 // serializeBefore makes the instruction wait in rename until the ROB 620 // is empty. 621 622 // In this model, IPR accesses are serialize before 623 // instructions, and store conditionals are serialize after 624 // instructions. This is mainly due to lack of support for 625 // out-of-order operations of either of those classes of 626 // instructions. 627 if ((inst->isIprAccess() || inst->isSerializeBefore()) && 628 !inst->isSerializeHandled()) { 629 DPRINTF(Rename, "Serialize before instruction encountered.\n"); 630 631 if (!inst->isTempSerializeBefore()) { 632 renamedSerializing++; 633 inst->setSerializeHandled(); 634 } else { 635 renamedTempSerializing++; 636 } 637 638 // Change status over to SerializeStall so that other stages know 639 // what this is blocked on. 640 renameStatus[tid] = SerializeStall; 641 642 serializeInst[tid] = inst; 643 644 blockThisCycle = true; 645 646 break; 647 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) && 648 !inst->isSerializeHandled()) { 649 DPRINTF(Rename, "Serialize after instruction encountered.\n"); 650 651 renamedSerializing++; 652 653 inst->setSerializeHandled(); 654 655 serializeAfter(insts_to_rename, tid); 656 } 657 658 renameSrcRegs(inst, inst->threadNumber); 659 660 renameDestRegs(inst, inst->threadNumber); 661 662 ++renamed_insts; 663 664 665 // Put instruction in rename queue. 666 toIEW->insts[toIEWIndex] = inst; 667 ++(toIEW->size); 668 669 // Increment which instruction we're on. 670 ++toIEWIndex; 671 672 // Decrement how many instructions are available. 673 --insts_available; 674 } 675 676 instsInProgress[tid] += renamed_insts; 677 renameRenamedInsts += renamed_insts; 678 679 // If we wrote to the time buffer, record this. 680 if (toIEWIndex) { 681 wroteToTimeBuffer = true; 682 } 683 684 // Check if there's any instructions left that haven't yet been renamed. 685 // If so then block. 686 if (insts_available) { 687 blockThisCycle = true; 688 } 689 690 if (blockThisCycle) { 691 block(tid); 692 toDecode->renameUnblock[tid] = false; 693 } 694} 695 696template<class Impl> 697void 698DefaultRename<Impl>::skidInsert(ThreadID tid) 699{ 700 DynInstPtr inst = NULL; 701 702 while (!insts[tid].empty()) { 703 inst = insts[tid].front(); 704 705 insts[tid].pop_front(); 706 707 assert(tid == inst->threadNumber); 708 709 DPRINTF(Rename, "[tid:%u]: Inserting [sn:%lli] PC: %s into Rename " 710 "skidBuffer\n", tid, inst->seqNum, inst->pcState()); 711 712 ++renameSkidInsts; 713 714 skidBuffer[tid].push_back(inst); 715 } 716 717 if (skidBuffer[tid].size() > skidBufferMax) 718 { 719 typename InstQueue::iterator it; 720 warn("Skidbuffer contents:\n"); 721 for(it = skidBuffer[tid].begin(); it != skidBuffer[tid].end(); it++) 722 { 723 warn("[tid:%u]: %s [sn:%i].\n", tid, 724 (*it)->staticInst->disassemble(inst->instAddr()), 725 (*it)->seqNum); 726 } 727 panic("Skidbuffer Exceeded Max Size"); 728 } 729} 730 731template <class Impl> 732void 733DefaultRename<Impl>::sortInsts() 734{ 735 int insts_from_decode = fromDecode->size; 736 for (int i = 0; i < insts_from_decode; ++i) { 737 DynInstPtr inst = fromDecode->insts[i]; 738 insts[inst->threadNumber].push_back(inst); 739#if TRACING_ON 740 if (DTRACE(O3PipeView)) { 741 inst->renameTick = curTick() - inst->fetchTick; 742 } 743#endif 744 } 745} 746 747template<class Impl> 748bool 749DefaultRename<Impl>::skidsEmpty() 750{ 751 list<ThreadID>::iterator threads = activeThreads->begin(); 752 list<ThreadID>::iterator end = activeThreads->end(); 753 754 while (threads != end) { 755 ThreadID tid = *threads++; 756 757 if (!skidBuffer[tid].empty()) 758 return false; 759 } 760 761 return true; 762} 763 764template<class Impl> 765void 766DefaultRename<Impl>::updateStatus() 767{ 768 bool any_unblocking = false; 769 770 list<ThreadID>::iterator threads = activeThreads->begin(); 771 list<ThreadID>::iterator end = activeThreads->end(); 772 773 while (threads != end) { 774 ThreadID tid = *threads++; 775 776 if (renameStatus[tid] == Unblocking) { 777 any_unblocking = true; 778 break; 779 } 780 } 781 782 // Rename will have activity if it's unblocking. 783 if (any_unblocking) { 784 if (_status == Inactive) { 785 _status = Active; 786 787 DPRINTF(Activity, "Activating stage.\n"); 788 789 cpu->activateStage(O3CPU::RenameIdx); 790 } 791 } else { 792 // If it's not unblocking, then rename will not have any internal 793 // activity. Switch it to inactive. 794 if (_status == Active) { 795 _status = Inactive; 796 DPRINTF(Activity, "Deactivating stage.\n"); 797 798 cpu->deactivateStage(O3CPU::RenameIdx); 799 } 800 } 801} 802 803template <class Impl> 804bool 805DefaultRename<Impl>::block(ThreadID tid) 806{ 807 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid); 808 809 // Add the current inputs onto the skid buffer, so they can be 810 // reprocessed when this stage unblocks. 811 skidInsert(tid); 812 813 // Only signal backwards to block if the previous stages do not think 814 // rename is already blocked. 815 if (renameStatus[tid] != Blocked) { 816 // If resumeUnblocking is set, we unblocked during the squash, 817 // but now we're have unblocking status. We need to tell earlier 818 // stages to block. 819 if (resumeUnblocking || renameStatus[tid] != Unblocking) { 820 toDecode->renameBlock[tid] = true; 821 toDecode->renameUnblock[tid] = false; 822 wroteToTimeBuffer = true; 823 } 824 825 // Rename can not go from SerializeStall to Blocked, otherwise 826 // it would not know to complete the serialize stall. 827 if (renameStatus[tid] != SerializeStall) { 828 // Set status to Blocked. 829 renameStatus[tid] = Blocked; 830 return true; 831 } 832 } 833 834 return false; 835} 836 837template <class Impl> 838bool 839DefaultRename<Impl>::unblock(ThreadID tid) 840{ 841 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid); 842 843 // Rename is done unblocking if the skid buffer is empty. 844 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) { 845 846 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid); 847 848 toDecode->renameUnblock[tid] = true; 849 wroteToTimeBuffer = true; 850 851 renameStatus[tid] = Running; 852 return true; 853 } 854 855 return false; 856} 857 858template <class Impl> 859void 860DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, ThreadID tid) 861{ 862 typename std::list<RenameHistory>::iterator hb_it = 863 historyBuffer[tid].begin(); 864 865 // After a syscall squashes everything, the history buffer may be empty 866 // but the ROB may still be squashing instructions. 867 if (historyBuffer[tid].empty()) { 868 return; 869 } 870 871 // Go through the most recent instructions, undoing the mappings 872 // they did and freeing up the registers. 873 while (!historyBuffer[tid].empty() && 874 hb_it->instSeqNum > squashed_seq_num) { 875 assert(hb_it != historyBuffer[tid].end()); 876 877 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence " 878 "number %i.\n", tid, hb_it->instSeqNum); 879 880 // Undo the rename mapping only if it was really a change. 881 // Special regs that are not really renamed (like misc regs 882 // and the zero reg) can be recognized because the new mapping 883 // is the same as the old one. While it would be merely a 884 // waste of time to update the rename table, we definitely 885 // don't want to put these on the free list. 886 if (hb_it->newPhysReg != hb_it->prevPhysReg) { 887 // Tell the rename map to set the architected register to the 888 // previous physical register that it was renamed to. 889 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg); 890 891 // Put the renamed physical register back on the free list. 892 freeList->addReg(hb_it->newPhysReg); 893 } 894 895 historyBuffer[tid].erase(hb_it++); 896 897 ++renameUndoneMaps; 898 } 899} 900 901template<class Impl> 902void 903DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, ThreadID tid) 904{ 905 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the " 906 "history buffer %u (size=%i), until [sn:%lli].\n", 907 tid, tid, historyBuffer[tid].size(), inst_seq_num); 908 909 typename std::list<RenameHistory>::iterator hb_it = 910 historyBuffer[tid].end(); 911 912 --hb_it; 913 914 if (historyBuffer[tid].empty()) { 915 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid); 916 return; 917 } else if (hb_it->instSeqNum > inst_seq_num) { 918 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure " 919 "that a syscall happened recently.\n", tid); 920 return; 921 } 922 923 // Commit all the renames up until (and including) the committed sequence 924 // number. Some or even all of the committed instructions may not have 925 // rename histories if they did not have destination registers that were 926 // renamed. 927 while (!historyBuffer[tid].empty() && 928 hb_it != historyBuffer[tid].end() && 929 hb_it->instSeqNum <= inst_seq_num) { 930 931 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, " 932 "[sn:%lli].\n", 933 tid, hb_it->prevPhysReg, hb_it->instSeqNum); 934 935 // Don't free special phys regs like misc and zero regs, which 936 // can be recognized because the new mapping is the same as 937 // the old one. 938 if (hb_it->newPhysReg != hb_it->prevPhysReg) { 939 freeList->addReg(hb_it->prevPhysReg); 940 } 941 942 ++renameCommittedMaps; 943 944 historyBuffer[tid].erase(hb_it--); 945 } 946} 947 948template <class Impl> 949inline void 950DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst, ThreadID tid) 951{ 952 ThreadContext *tc = inst->tcBase(); 953 RenameMap *map = renameMap[tid]; 954 unsigned num_src_regs = inst->numSrcRegs(); 955 956 // Get the architectual register numbers from the source and 957 // operands, and redirect them to the right physical register. 958 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) { 959 RegIndex src_reg = inst->srcRegIdx(src_idx); 960 RegIndex rel_src_reg; 961 RegIndex flat_rel_src_reg; 962 PhysRegIndex renamed_reg; 963 964 switch (regIdxToClass(src_reg, &rel_src_reg)) { 965 case IntRegClass: 966 flat_rel_src_reg = tc->flattenIntIndex(rel_src_reg); 967 renamed_reg = map->lookupInt(flat_rel_src_reg); 968 intRenameLookups++; 969 break; 970 971 case FloatRegClass: 972 flat_rel_src_reg = tc->flattenFloatIndex(rel_src_reg); 973 renamed_reg = map->lookupFloat(flat_rel_src_reg); 974 fpRenameLookups++; 975 break; 976 977 case MiscRegClass: 978 // misc regs don't get flattened 979 flat_rel_src_reg = rel_src_reg; 980 renamed_reg = map->lookupMisc(flat_rel_src_reg); 981 break; 982 983 default: 984 panic("Reg index is out of bound: %d.", src_reg); 985 } 986 987 DPRINTF(Rename, "[tid:%u]: Looking up %s arch reg %i (flattened %i), " 988 "got phys reg %i\n", tid, RegClassStrings[regIdxToClass(src_reg)], 989 (int)src_reg, (int)flat_rel_src_reg, (int)renamed_reg); 990 991 inst->renameSrcReg(src_idx, renamed_reg); 992 993 // See if the register is ready or not. 994 if (scoreboard->getReg(renamed_reg)) { 995 DPRINTF(Rename, "[tid:%u]: Register %d is ready.\n", 996 tid, renamed_reg); 997 998 inst->markSrcRegReady(src_idx); 999 } else { 1000 DPRINTF(Rename, "[tid:%u]: Register %d is not ready.\n", 1001 tid, renamed_reg); 1002 } 1003 1004 ++renameRenameLookups; 1005 } 1006} 1007 1008template <class Impl> 1009inline void 1010DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst, ThreadID tid) 1011{ 1012 ThreadContext *tc = inst->tcBase(); 1013 RenameMap *map = renameMap[tid]; 1014 unsigned num_dest_regs = inst->numDestRegs(); 1015 1016 // Rename the destination registers. 1017 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) { 1018 RegIndex dest_reg = inst->destRegIdx(dest_idx); 1019 RegIndex rel_dest_reg; 1020 RegIndex flat_rel_dest_reg; 1021 RegIndex flat_uni_dest_reg; 1022 typename RenameMap::RenameInfo rename_result; 1023 1024 switch (regIdxToClass(dest_reg, &rel_dest_reg)) { 1025 case IntRegClass: 1026 flat_rel_dest_reg = tc->flattenIntIndex(rel_dest_reg); 1027 rename_result = map->renameInt(flat_rel_dest_reg); 1028 flat_uni_dest_reg = flat_rel_dest_reg; // 1:1 mapping 1029 break; 1030 1031 case FloatRegClass: 1032 flat_rel_dest_reg = tc->flattenFloatIndex(rel_dest_reg); 1033 rename_result = map->renameFloat(flat_rel_dest_reg); 1034 flat_uni_dest_reg = flat_rel_dest_reg + TheISA::FP_Reg_Base; 1035 break; 1036 1037 case MiscRegClass: 1038 // misc regs don't get flattened 1039 flat_rel_dest_reg = rel_dest_reg; 1040 rename_result = map->renameMisc(flat_rel_dest_reg); 1041 flat_uni_dest_reg = flat_rel_dest_reg + TheISA::Misc_Reg_Base; 1042 break; 1043 1044 default: 1045 panic("Reg index is out of bound: %d.", dest_reg); 1046 } 1047 1048 inst->flattenDestReg(dest_idx, flat_uni_dest_reg); 1049 1050 // Mark Scoreboard entry as not ready 1051 scoreboard->unsetReg(rename_result.first); 1052 1053 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical " 1054 "reg %i.\n", tid, (int)flat_rel_dest_reg, 1055 (int)rename_result.first); 1056 1057 // Record the rename information so that a history can be kept. 1058 RenameHistory hb_entry(inst->seqNum, flat_uni_dest_reg, 1059 rename_result.first, 1060 rename_result.second); 1061 1062 historyBuffer[tid].push_front(hb_entry); 1063 1064 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer " 1065 "(size=%i), [sn:%lli].\n",tid, 1066 historyBuffer[tid].size(), 1067 (*historyBuffer[tid].begin()).instSeqNum); 1068 1069 // Tell the instruction to rename the appropriate destination 1070 // register (dest_idx) to the new physical register 1071 // (rename_result.first), and record the previous physical 1072 // register that the same logical register was renamed to 1073 // (rename_result.second). 1074 inst->renameDestReg(dest_idx, 1075 rename_result.first, 1076 rename_result.second); 1077 1078 ++renameRenamedOperands; 1079 } 1080} 1081 1082template <class Impl> 1083inline int 1084DefaultRename<Impl>::calcFreeROBEntries(ThreadID tid) 1085{ 1086 int num_free = freeEntries[tid].robEntries - 1087 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched); 1088 1089 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free); 1090 1091 return num_free; 1092} 1093 1094template <class Impl> 1095inline int 1096DefaultRename<Impl>::calcFreeIQEntries(ThreadID tid) 1097{ 1098 int num_free = freeEntries[tid].iqEntries - 1099 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched); 1100 1101 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free); 1102 1103 return num_free; 1104} 1105 1106template <class Impl> 1107inline int 1108DefaultRename<Impl>::calcFreeLSQEntries(ThreadID tid) 1109{ 1110 int num_free = freeEntries[tid].lsqEntries - 1111 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ); 1112 1113 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free); 1114 1115 return num_free; 1116} 1117 1118template <class Impl> 1119unsigned 1120DefaultRename<Impl>::validInsts() 1121{ 1122 unsigned inst_count = 0; 1123 1124 for (int i=0; i<fromDecode->size; i++) { 1125 if (!fromDecode->insts[i]->isSquashed()) 1126 inst_count++; 1127 } 1128 1129 return inst_count; 1130} 1131 1132template <class Impl> 1133void 1134DefaultRename<Impl>::readStallSignals(ThreadID tid) 1135{ 1136 if (fromIEW->iewBlock[tid]) { 1137 stalls[tid].iew = true; 1138 } 1139 1140 if (fromIEW->iewUnblock[tid]) { 1141 assert(stalls[tid].iew); 1142 stalls[tid].iew = false; 1143 } 1144 1145 if (fromCommit->commitBlock[tid]) { 1146 stalls[tid].commit = true; 1147 } 1148 1149 if (fromCommit->commitUnblock[tid]) { 1150 assert(stalls[tid].commit); 1151 stalls[tid].commit = false; 1152 } 1153} 1154 1155template <class Impl> 1156bool 1157DefaultRename<Impl>::checkStall(ThreadID tid) 1158{ 1159 bool ret_val = false; 1160 1161 if (stalls[tid].iew) { 1162 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid); 1163 ret_val = true; 1164 } else if (stalls[tid].commit) { 1165 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid); 1166 ret_val = true; 1167 } else if (calcFreeROBEntries(tid) <= 0) { 1168 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid); 1169 ret_val = true; 1170 } else if (calcFreeIQEntries(tid) <= 0) { 1171 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid); 1172 ret_val = true; 1173 } else if (calcFreeLSQEntries(tid) <= 0) { 1174 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid); 1175 ret_val = true; 1176 } else if (renameMap[tid]->numFreeEntries() <= 0) { 1177 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid); 1178 ret_val = true; 1179 } else if (renameStatus[tid] == SerializeStall && 1180 (!emptyROB[tid] || instsInProgress[tid])) { 1181 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not " 1182 "empty.\n", 1183 tid); 1184 ret_val = true; 1185 } 1186 1187 return ret_val; 1188} 1189 1190template <class Impl> 1191void 1192DefaultRename<Impl>::readFreeEntries(ThreadID tid) 1193{ 1194 if (fromIEW->iewInfo[tid].usedIQ) 1195 freeEntries[tid].iqEntries = fromIEW->iewInfo[tid].freeIQEntries; 1196 1197 if (fromIEW->iewInfo[tid].usedLSQ) 1198 freeEntries[tid].lsqEntries = fromIEW->iewInfo[tid].freeLSQEntries; 1199 1200 if (fromCommit->commitInfo[tid].usedROB) { 1201 freeEntries[tid].robEntries = 1202 fromCommit->commitInfo[tid].freeROBEntries; 1203 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB; 1204 } 1205 1206 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n", 1207 tid, 1208 freeEntries[tid].iqEntries, 1209 freeEntries[tid].robEntries, 1210 freeEntries[tid].lsqEntries); 1211 1212 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n", 1213 tid, instsInProgress[tid]); 1214} 1215 1216template <class Impl> 1217bool 1218DefaultRename<Impl>::checkSignalsAndUpdate(ThreadID tid) 1219{ 1220 // Check if there's a squash signal, squash if there is 1221 // Check stall signals, block if necessary. 1222 // If status was blocked 1223 // check if stall conditions have passed 1224 // if so then go to unblocking 1225 // If status was Squashing 1226 // check if squashing is not high. Switch to running this cycle. 1227 // If status was serialize stall 1228 // check if ROB is empty and no insts are in flight to the ROB 1229 1230 readFreeEntries(tid); 1231 readStallSignals(tid); 1232 1233 if (fromCommit->commitInfo[tid].squash) { 1234 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from " 1235 "commit.\n", tid); 1236 1237 squash(fromCommit->commitInfo[tid].doneSeqNum, tid); 1238 1239 return true; 1240 } 1241 1242 if (fromCommit->commitInfo[tid].robSquashing) { 1243 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid); 1244 1245 renameStatus[tid] = Squashing; 1246 1247 return true; 1248 } 1249 1250 if (checkStall(tid)) { 1251 return block(tid); 1252 } 1253 1254 if (renameStatus[tid] == Blocked) { 1255 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n", 1256 tid); 1257 1258 renameStatus[tid] = Unblocking; 1259 1260 unblock(tid); 1261 1262 return true; 1263 } 1264 1265 if (renameStatus[tid] == Squashing) { 1266 // Switch status to running if rename isn't being told to block or 1267 // squash this cycle. 1268 if (resumeSerialize) { 1269 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to serialize.\n", 1270 tid); 1271 1272 renameStatus[tid] = SerializeStall; 1273 return true; 1274 } else if (resumeUnblocking) { 1275 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to unblocking.\n", 1276 tid); 1277 renameStatus[tid] = Unblocking; 1278 return true; 1279 } else { 1280 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n", 1281 tid); 1282 1283 renameStatus[tid] = Running; 1284 return false; 1285 } 1286 } 1287 1288 if (renameStatus[tid] == SerializeStall) { 1289 // Stall ends once the ROB is free. 1290 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to " 1291 "unblocking.\n", tid); 1292 1293 DynInstPtr serial_inst = serializeInst[tid]; 1294 1295 renameStatus[tid] = Unblocking; 1296 1297 unblock(tid); 1298 1299 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with " 1300 "PC %s.\n", tid, serial_inst->seqNum, serial_inst->pcState()); 1301 1302 // Put instruction into queue here. 1303 serial_inst->clearSerializeBefore(); 1304 1305 if (!skidBuffer[tid].empty()) { 1306 skidBuffer[tid].push_front(serial_inst); 1307 } else { 1308 insts[tid].push_front(serial_inst); 1309 } 1310 1311 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename." 1312 " Adding to front of list.\n", tid); 1313 1314 serializeInst[tid] = NULL; 1315 1316 return true; 1317 } 1318 1319 // If we've reached this point, we have not gotten any signals that 1320 // cause rename to change its status. Rename remains the same as before. 1321 return false; 1322} 1323 1324template<class Impl> 1325void 1326DefaultRename<Impl>::serializeAfter(InstQueue &inst_list, ThreadID tid) 1327{ 1328 if (inst_list.empty()) { 1329 // Mark a bit to say that I must serialize on the next instruction. 1330 serializeOnNextInst[tid] = true; 1331 return; 1332 } 1333 1334 // Set the next instruction as serializing. 1335 inst_list.front()->setSerializeBefore(); 1336} 1337 1338template <class Impl> 1339inline void 1340DefaultRename<Impl>::incrFullStat(const FullSource &source) 1341{ 1342 switch (source) { 1343 case ROB: 1344 ++renameROBFullEvents; 1345 break; 1346 case IQ: 1347 ++renameIQFullEvents; 1348 break; 1349 case LSQ: 1350 ++renameLSQFullEvents; 1351 break; 1352 default: 1353 panic("Rename full stall stat should be incremented for a reason!"); 1354 break; 1355 } 1356} 1357 1358template <class Impl> 1359void 1360DefaultRename<Impl>::dumpHistory() 1361{ 1362 typename std::list<RenameHistory>::iterator buf_it; 1363 1364 for (ThreadID tid = 0; tid < numThreads; tid++) { 1365 1366 buf_it = historyBuffer[tid].begin(); 1367 1368 while (buf_it != historyBuffer[tid].end()) { 1369 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys " 1370 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg, 1371 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg); 1372 1373 buf_it++; 1374 } 1375 } 1376} 1377