rename_impl.hh revision 9444
1/* 2 * Copyright (c) 2010-2012 ARM Limited 3 * All rights reserved. 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2004-2006 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Kevin Lim 41 * Korey Sewell 42 */ 43 44#include <list> 45 46#include "arch/isa_traits.hh" 47#include "arch/registers.hh" 48#include "config/the_isa.hh" 49#include "cpu/o3/rename.hh" 50#include "debug/Activity.hh" 51#include "debug/Rename.hh" 52#include "params/DerivO3CPU.hh" 53 54using namespace std; 55 56template <class Impl> 57DefaultRename<Impl>::DefaultRename(O3CPU *_cpu, DerivO3CPUParams *params) 58 : cpu(_cpu), 59 iewToRenameDelay(params->iewToRenameDelay), 60 decodeToRenameDelay(params->decodeToRenameDelay), 61 commitToRenameDelay(params->commitToRenameDelay), 62 renameWidth(params->renameWidth), 63 commitWidth(params->commitWidth), 64 numThreads(params->numThreads), 65 maxPhysicalRegs(params->numPhysIntRegs + params->numPhysFloatRegs) 66{ 67 // @todo: Make into a parameter. 68 skidBufferMax = (2 * (decodeToRenameDelay * params->decodeWidth)) + renameWidth; 69} 70 71template <class Impl> 72std::string 73DefaultRename<Impl>::name() const 74{ 75 return cpu->name() + ".rename"; 76} 77 78template <class Impl> 79void 80DefaultRename<Impl>::regStats() 81{ 82 renameSquashCycles 83 .name(name() + ".SquashCycles") 84 .desc("Number of cycles rename is squashing") 85 .prereq(renameSquashCycles); 86 renameIdleCycles 87 .name(name() + ".IdleCycles") 88 .desc("Number of cycles rename is idle") 89 .prereq(renameIdleCycles); 90 renameBlockCycles 91 .name(name() + ".BlockCycles") 92 .desc("Number of cycles rename is blocking") 93 .prereq(renameBlockCycles); 94 renameSerializeStallCycles 95 .name(name() + ".serializeStallCycles") 96 .desc("count of cycles rename stalled for serializing inst") 97 .flags(Stats::total); 98 renameRunCycles 99 .name(name() + ".RunCycles") 100 .desc("Number of cycles rename is running") 101 .prereq(renameIdleCycles); 102 renameUnblockCycles 103 .name(name() + ".UnblockCycles") 104 .desc("Number of cycles rename is unblocking") 105 .prereq(renameUnblockCycles); 106 renameRenamedInsts 107 .name(name() + ".RenamedInsts") 108 .desc("Number of instructions processed by rename") 109 .prereq(renameRenamedInsts); 110 renameSquashedInsts 111 .name(name() + ".SquashedInsts") 112 .desc("Number of squashed instructions processed by rename") 113 .prereq(renameSquashedInsts); 114 renameROBFullEvents 115 .name(name() + ".ROBFullEvents") 116 .desc("Number of times rename has blocked due to ROB full") 117 .prereq(renameROBFullEvents); 118 renameIQFullEvents 119 .name(name() + ".IQFullEvents") 120 .desc("Number of times rename has blocked due to IQ full") 121 .prereq(renameIQFullEvents); 122 renameLSQFullEvents 123 .name(name() + ".LSQFullEvents") 124 .desc("Number of times rename has blocked due to LSQ full") 125 .prereq(renameLSQFullEvents); 126 renameFullRegistersEvents 127 .name(name() + ".FullRegisterEvents") 128 .desc("Number of times there has been no free registers") 129 .prereq(renameFullRegistersEvents); 130 renameRenamedOperands 131 .name(name() + ".RenamedOperands") 132 .desc("Number of destination operands rename has renamed") 133 .prereq(renameRenamedOperands); 134 renameRenameLookups 135 .name(name() + ".RenameLookups") 136 .desc("Number of register rename lookups that rename has made") 137 .prereq(renameRenameLookups); 138 renameCommittedMaps 139 .name(name() + ".CommittedMaps") 140 .desc("Number of HB maps that are committed") 141 .prereq(renameCommittedMaps); 142 renameUndoneMaps 143 .name(name() + ".UndoneMaps") 144 .desc("Number of HB maps that are undone due to squashing") 145 .prereq(renameUndoneMaps); 146 renamedSerializing 147 .name(name() + ".serializingInsts") 148 .desc("count of serializing insts renamed") 149 .flags(Stats::total) 150 ; 151 renamedTempSerializing 152 .name(name() + ".tempSerializingInsts") 153 .desc("count of temporary serializing insts renamed") 154 .flags(Stats::total) 155 ; 156 renameSkidInsts 157 .name(name() + ".skidInsts") 158 .desc("count of insts added to the skid buffer") 159 .flags(Stats::total) 160 ; 161 intRenameLookups 162 .name(name() + ".int_rename_lookups") 163 .desc("Number of integer rename lookups") 164 .prereq(intRenameLookups); 165 fpRenameLookups 166 .name(name() + ".fp_rename_lookups") 167 .desc("Number of floating rename lookups") 168 .prereq(fpRenameLookups); 169} 170 171template <class Impl> 172void 173DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) 174{ 175 timeBuffer = tb_ptr; 176 177 // Setup wire to read information from time buffer, from IEW stage. 178 fromIEW = timeBuffer->getWire(-iewToRenameDelay); 179 180 // Setup wire to read infromation from time buffer, from commit stage. 181 fromCommit = timeBuffer->getWire(-commitToRenameDelay); 182 183 // Setup wire to write information to previous stages. 184 toDecode = timeBuffer->getWire(0); 185} 186 187template <class Impl> 188void 189DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) 190{ 191 renameQueue = rq_ptr; 192 193 // Setup wire to write information to future stages. 194 toIEW = renameQueue->getWire(0); 195} 196 197template <class Impl> 198void 199DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr) 200{ 201 decodeQueue = dq_ptr; 202 203 // Setup wire to get information from decode. 204 fromDecode = decodeQueue->getWire(-decodeToRenameDelay); 205} 206 207template <class Impl> 208void 209DefaultRename<Impl>::startupStage() 210{ 211 resetStage(); 212} 213 214template <class Impl> 215void 216DefaultRename<Impl>::resetStage() 217{ 218 _status = Inactive; 219 220 resumeSerialize = false; 221 resumeUnblocking = false; 222 223 // Grab the number of free entries directly from the stages. 224 for (ThreadID tid = 0; tid < numThreads; tid++) { 225 renameStatus[tid] = Idle; 226 227 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid); 228 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid); 229 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid); 230 emptyROB[tid] = true; 231 232 stalls[tid].iew = false; 233 stalls[tid].commit = false; 234 serializeInst[tid] = NULL; 235 236 instsInProgress[tid] = 0; 237 238 serializeOnNextInst[tid] = false; 239 } 240} 241 242template<class Impl> 243void 244DefaultRename<Impl>::setActiveThreads(list<ThreadID> *at_ptr) 245{ 246 activeThreads = at_ptr; 247} 248 249 250template <class Impl> 251void 252DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[]) 253{ 254 for (ThreadID tid = 0; tid < numThreads; tid++) 255 renameMap[tid] = &rm_ptr[tid]; 256} 257 258template <class Impl> 259void 260DefaultRename<Impl>::setFreeList(FreeList *fl_ptr) 261{ 262 freeList = fl_ptr; 263} 264 265template<class Impl> 266void 267DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard) 268{ 269 scoreboard = _scoreboard; 270} 271 272template <class Impl> 273bool 274DefaultRename<Impl>::isDrained() const 275{ 276 for (ThreadID tid = 0; tid < numThreads; tid++) { 277 if (instsInProgress[tid] != 0 || 278 !historyBuffer[tid].empty() || 279 !skidBuffer[tid].empty() || 280 !insts[tid].empty()) 281 return false; 282 } 283 return true; 284} 285 286template <class Impl> 287void 288DefaultRename<Impl>::takeOverFrom() 289{ 290 resetStage(); 291} 292 293template <class Impl> 294void 295DefaultRename<Impl>::drainSanityCheck() const 296{ 297 for (ThreadID tid = 0; tid < numThreads; tid++) { 298 assert(historyBuffer[tid].empty()); 299 assert(insts[tid].empty()); 300 assert(skidBuffer[tid].empty()); 301 assert(instsInProgress[tid] == 0); 302 } 303} 304 305template <class Impl> 306void 307DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, ThreadID tid) 308{ 309 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid); 310 311 // Clear the stall signal if rename was blocked or unblocking before. 312 // If it still needs to block, the blocking should happen the next 313 // cycle and there should be space to hold everything due to the squash. 314 if (renameStatus[tid] == Blocked || 315 renameStatus[tid] == Unblocking) { 316 toDecode->renameUnblock[tid] = 1; 317 318 resumeSerialize = false; 319 serializeInst[tid] = NULL; 320 } else if (renameStatus[tid] == SerializeStall) { 321 if (serializeInst[tid]->seqNum <= squash_seq_num) { 322 DPRINTF(Rename, "Rename will resume serializing after squash\n"); 323 resumeSerialize = true; 324 assert(serializeInst[tid]); 325 } else { 326 resumeSerialize = false; 327 toDecode->renameUnblock[tid] = 1; 328 329 serializeInst[tid] = NULL; 330 } 331 } 332 333 // Set the status to Squashing. 334 renameStatus[tid] = Squashing; 335 336 // Squash any instructions from decode. 337 unsigned squashCount = 0; 338 339 for (int i=0; i<fromDecode->size; i++) { 340 if (fromDecode->insts[i]->threadNumber == tid && 341 fromDecode->insts[i]->seqNum > squash_seq_num) { 342 fromDecode->insts[i]->setSquashed(); 343 wroteToTimeBuffer = true; 344 squashCount++; 345 } 346 347 } 348 349 // Clear the instruction list and skid buffer in case they have any 350 // insts in them. 351 insts[tid].clear(); 352 353 // Clear the skid buffer in case it has any data in it. 354 skidBuffer[tid].clear(); 355 356 doSquash(squash_seq_num, tid); 357} 358 359template <class Impl> 360void 361DefaultRename<Impl>::tick() 362{ 363 wroteToTimeBuffer = false; 364 365 blockThisCycle = false; 366 367 bool status_change = false; 368 369 toIEWIndex = 0; 370 371 sortInsts(); 372 373 list<ThreadID>::iterator threads = activeThreads->begin(); 374 list<ThreadID>::iterator end = activeThreads->end(); 375 376 // Check stall and squash signals. 377 while (threads != end) { 378 ThreadID tid = *threads++; 379 380 DPRINTF(Rename, "Processing [tid:%i]\n", tid); 381 382 status_change = checkSignalsAndUpdate(tid) || status_change; 383 384 rename(status_change, tid); 385 } 386 387 if (status_change) { 388 updateStatus(); 389 } 390 391 if (wroteToTimeBuffer) { 392 DPRINTF(Activity, "Activity this cycle.\n"); 393 cpu->activityThisCycle(); 394 } 395 396 threads = activeThreads->begin(); 397 398 while (threads != end) { 399 ThreadID tid = *threads++; 400 401 // If we committed this cycle then doneSeqNum will be > 0 402 if (fromCommit->commitInfo[tid].doneSeqNum != 0 && 403 !fromCommit->commitInfo[tid].squash && 404 renameStatus[tid] != Squashing) { 405 406 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum, 407 tid); 408 } 409 } 410 411 // @todo: make into updateProgress function 412 for (ThreadID tid = 0; tid < numThreads; tid++) { 413 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched; 414 415 assert(instsInProgress[tid] >=0); 416 } 417 418} 419 420template<class Impl> 421void 422DefaultRename<Impl>::rename(bool &status_change, ThreadID tid) 423{ 424 // If status is Running or idle, 425 // call renameInsts() 426 // If status is Unblocking, 427 // buffer any instructions coming from decode 428 // continue trying to empty skid buffer 429 // check if stall conditions have passed 430 431 if (renameStatus[tid] == Blocked) { 432 ++renameBlockCycles; 433 } else if (renameStatus[tid] == Squashing) { 434 ++renameSquashCycles; 435 } else if (renameStatus[tid] == SerializeStall) { 436 ++renameSerializeStallCycles; 437 // If we are currently in SerializeStall and resumeSerialize 438 // was set, then that means that we are resuming serializing 439 // this cycle. Tell the previous stages to block. 440 if (resumeSerialize) { 441 resumeSerialize = false; 442 block(tid); 443 toDecode->renameUnblock[tid] = false; 444 } 445 } else if (renameStatus[tid] == Unblocking) { 446 if (resumeUnblocking) { 447 block(tid); 448 resumeUnblocking = false; 449 toDecode->renameUnblock[tid] = false; 450 } 451 } 452 453 if (renameStatus[tid] == Running || 454 renameStatus[tid] == Idle) { 455 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run " 456 "stage.\n", tid); 457 458 renameInsts(tid); 459 } else if (renameStatus[tid] == Unblocking) { 460 renameInsts(tid); 461 462 if (validInsts()) { 463 // Add the current inputs to the skid buffer so they can be 464 // reprocessed when this stage unblocks. 465 skidInsert(tid); 466 } 467 468 // If we switched over to blocking, then there's a potential for 469 // an overall status change. 470 status_change = unblock(tid) || status_change || blockThisCycle; 471 } 472} 473 474template <class Impl> 475void 476DefaultRename<Impl>::renameInsts(ThreadID tid) 477{ 478 // Instructions can be either in the skid buffer or the queue of 479 // instructions coming from decode, depending on the status. 480 int insts_available = renameStatus[tid] == Unblocking ? 481 skidBuffer[tid].size() : insts[tid].size(); 482 483 // Check the decode queue to see if instructions are available. 484 // If there are no available instructions to rename, then do nothing. 485 if (insts_available == 0) { 486 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n", 487 tid); 488 // Should I change status to idle? 489 ++renameIdleCycles; 490 return; 491 } else if (renameStatus[tid] == Unblocking) { 492 ++renameUnblockCycles; 493 } else if (renameStatus[tid] == Running) { 494 ++renameRunCycles; 495 } 496 497 DynInstPtr inst; 498 499 // Will have to do a different calculation for the number of free 500 // entries. 501 int free_rob_entries = calcFreeROBEntries(tid); 502 int free_iq_entries = calcFreeIQEntries(tid); 503 int free_lsq_entries = calcFreeLSQEntries(tid); 504 int min_free_entries = free_rob_entries; 505 506 FullSource source = ROB; 507 508 if (free_iq_entries < min_free_entries) { 509 min_free_entries = free_iq_entries; 510 source = IQ; 511 } 512 513 if (free_lsq_entries < min_free_entries) { 514 min_free_entries = free_lsq_entries; 515 source = LSQ; 516 } 517 518 // Check if there's any space left. 519 if (min_free_entries <= 0) { 520 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ " 521 "entries.\n" 522 "ROB has %i free entries.\n" 523 "IQ has %i free entries.\n" 524 "LSQ has %i free entries.\n", 525 tid, 526 free_rob_entries, 527 free_iq_entries, 528 free_lsq_entries); 529 530 blockThisCycle = true; 531 532 block(tid); 533 534 incrFullStat(source); 535 536 return; 537 } else if (min_free_entries < insts_available) { 538 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle." 539 "%i insts available, but only %i insts can be " 540 "renamed due to ROB/IQ/LSQ limits.\n", 541 tid, insts_available, min_free_entries); 542 543 insts_available = min_free_entries; 544 545 blockThisCycle = true; 546 547 incrFullStat(source); 548 } 549 550 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ? 551 skidBuffer[tid] : insts[tid]; 552 553 DPRINTF(Rename, "[tid:%u]: %i available instructions to " 554 "send iew.\n", tid, insts_available); 555 556 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts " 557 "dispatched to IQ last cycle.\n", 558 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched); 559 560 // Handle serializing the next instruction if necessary. 561 if (serializeOnNextInst[tid]) { 562 if (emptyROB[tid] && instsInProgress[tid] == 0) { 563 // ROB already empty; no need to serialize. 564 serializeOnNextInst[tid] = false; 565 } else if (!insts_to_rename.empty()) { 566 insts_to_rename.front()->setSerializeBefore(); 567 } 568 } 569 570 int renamed_insts = 0; 571 572 while (insts_available > 0 && toIEWIndex < renameWidth) { 573 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid); 574 575 assert(!insts_to_rename.empty()); 576 577 inst = insts_to_rename.front(); 578 579 insts_to_rename.pop_front(); 580 581 if (renameStatus[tid] == Unblocking) { 582 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%s from rename " 583 "skidBuffer\n", tid, inst->seqNum, inst->pcState()); 584 } 585 586 if (inst->isSquashed()) { 587 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %s is " 588 "squashed, skipping.\n", tid, inst->seqNum, 589 inst->pcState()); 590 591 ++renameSquashedInsts; 592 593 // Decrement how many instructions are available. 594 --insts_available; 595 596 continue; 597 } 598 599 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with " 600 "PC %s.\n", tid, inst->seqNum, inst->pcState()); 601 602 // Handle serializeAfter/serializeBefore instructions. 603 // serializeAfter marks the next instruction as serializeBefore. 604 // serializeBefore makes the instruction wait in rename until the ROB 605 // is empty. 606 607 // In this model, IPR accesses are serialize before 608 // instructions, and store conditionals are serialize after 609 // instructions. This is mainly due to lack of support for 610 // out-of-order operations of either of those classes of 611 // instructions. 612 if ((inst->isIprAccess() || inst->isSerializeBefore()) && 613 !inst->isSerializeHandled()) { 614 DPRINTF(Rename, "Serialize before instruction encountered.\n"); 615 616 if (!inst->isTempSerializeBefore()) { 617 renamedSerializing++; 618 inst->setSerializeHandled(); 619 } else { 620 renamedTempSerializing++; 621 } 622 623 // Change status over to SerializeStall so that other stages know 624 // what this is blocked on. 625 renameStatus[tid] = SerializeStall; 626 627 serializeInst[tid] = inst; 628 629 blockThisCycle = true; 630 631 break; 632 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) && 633 !inst->isSerializeHandled()) { 634 DPRINTF(Rename, "Serialize after instruction encountered.\n"); 635 636 renamedSerializing++; 637 638 inst->setSerializeHandled(); 639 640 serializeAfter(insts_to_rename, tid); 641 } 642 643 // Check here to make sure there are enough destination registers 644 // to rename to. Otherwise block. 645 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) { 646 DPRINTF(Rename, "Blocking due to lack of free " 647 "physical registers to rename to.\n"); 648 blockThisCycle = true; 649 insts_to_rename.push_front(inst); 650 ++renameFullRegistersEvents; 651 652 break; 653 } 654 655 renameSrcRegs(inst, inst->threadNumber); 656 657 renameDestRegs(inst, inst->threadNumber); 658 659 ++renamed_insts; 660 661#if TRACING_ON 662 inst->renameTick = curTick() - inst->fetchTick; 663#endif 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 } 740} 741 742template<class Impl> 743bool 744DefaultRename<Impl>::skidsEmpty() 745{ 746 list<ThreadID>::iterator threads = activeThreads->begin(); 747 list<ThreadID>::iterator end = activeThreads->end(); 748 749 while (threads != end) { 750 ThreadID tid = *threads++; 751 752 if (!skidBuffer[tid].empty()) 753 return false; 754 } 755 756 return true; 757} 758 759template<class Impl> 760void 761DefaultRename<Impl>::updateStatus() 762{ 763 bool any_unblocking = false; 764 765 list<ThreadID>::iterator threads = activeThreads->begin(); 766 list<ThreadID>::iterator end = activeThreads->end(); 767 768 while (threads != end) { 769 ThreadID tid = *threads++; 770 771 if (renameStatus[tid] == Unblocking) { 772 any_unblocking = true; 773 break; 774 } 775 } 776 777 // Rename will have activity if it's unblocking. 778 if (any_unblocking) { 779 if (_status == Inactive) { 780 _status = Active; 781 782 DPRINTF(Activity, "Activating stage.\n"); 783 784 cpu->activateStage(O3CPU::RenameIdx); 785 } 786 } else { 787 // If it's not unblocking, then rename will not have any internal 788 // activity. Switch it to inactive. 789 if (_status == Active) { 790 _status = Inactive; 791 DPRINTF(Activity, "Deactivating stage.\n"); 792 793 cpu->deactivateStage(O3CPU::RenameIdx); 794 } 795 } 796} 797 798template <class Impl> 799bool 800DefaultRename<Impl>::block(ThreadID tid) 801{ 802 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid); 803 804 // Add the current inputs onto the skid buffer, so they can be 805 // reprocessed when this stage unblocks. 806 skidInsert(tid); 807 808 // Only signal backwards to block if the previous stages do not think 809 // rename is already blocked. 810 if (renameStatus[tid] != Blocked) { 811 // If resumeUnblocking is set, we unblocked during the squash, 812 // but now we're have unblocking status. We need to tell earlier 813 // stages to block. 814 if (resumeUnblocking || renameStatus[tid] != Unblocking) { 815 toDecode->renameBlock[tid] = true; 816 toDecode->renameUnblock[tid] = false; 817 wroteToTimeBuffer = true; 818 } 819 820 // Rename can not go from SerializeStall to Blocked, otherwise 821 // it would not know to complete the serialize stall. 822 if (renameStatus[tid] != SerializeStall) { 823 // Set status to Blocked. 824 renameStatus[tid] = Blocked; 825 return true; 826 } 827 } 828 829 return false; 830} 831 832template <class Impl> 833bool 834DefaultRename<Impl>::unblock(ThreadID tid) 835{ 836 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid); 837 838 // Rename is done unblocking if the skid buffer is empty. 839 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) { 840 841 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid); 842 843 toDecode->renameUnblock[tid] = true; 844 wroteToTimeBuffer = true; 845 846 renameStatus[tid] = Running; 847 return true; 848 } 849 850 return false; 851} 852 853template <class Impl> 854void 855DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, ThreadID tid) 856{ 857 typename std::list<RenameHistory>::iterator hb_it = 858 historyBuffer[tid].begin(); 859 860 // After a syscall squashes everything, the history buffer may be empty 861 // but the ROB may still be squashing instructions. 862 if (historyBuffer[tid].empty()) { 863 return; 864 } 865 866 // Go through the most recent instructions, undoing the mappings 867 // they did and freeing up the registers. 868 while (!historyBuffer[tid].empty() && 869 (*hb_it).instSeqNum > squashed_seq_num) { 870 assert(hb_it != historyBuffer[tid].end()); 871 872 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence " 873 "number %i.\n", tid, (*hb_it).instSeqNum); 874 875 // Tell the rename map to set the architected register to the 876 // previous physical register that it was renamed to. 877 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg); 878 879 // Put the renamed physical register back on the free list. 880 freeList->addReg(hb_it->newPhysReg); 881 882 // Be sure to mark its register as ready if it's a misc register. 883 if (hb_it->newPhysReg >= maxPhysicalRegs) { 884 scoreboard->setReg(hb_it->newPhysReg); 885 } 886 887 historyBuffer[tid].erase(hb_it++); 888 889 ++renameUndoneMaps; 890 } 891} 892 893template<class Impl> 894void 895DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, ThreadID tid) 896{ 897 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the " 898 "history buffer %u (size=%i), until [sn:%lli].\n", 899 tid, tid, historyBuffer[tid].size(), inst_seq_num); 900 901 typename std::list<RenameHistory>::iterator hb_it = 902 historyBuffer[tid].end(); 903 904 --hb_it; 905 906 if (historyBuffer[tid].empty()) { 907 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid); 908 return; 909 } else if (hb_it->instSeqNum > inst_seq_num) { 910 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure " 911 "that a syscall happened recently.\n", tid); 912 return; 913 } 914 915 // Commit all the renames up until (and including) the committed sequence 916 // number. Some or even all of the committed instructions may not have 917 // rename histories if they did not have destination registers that were 918 // renamed. 919 while (!historyBuffer[tid].empty() && 920 hb_it != historyBuffer[tid].end() && 921 (*hb_it).instSeqNum <= inst_seq_num) { 922 923 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, " 924 "[sn:%lli].\n", 925 tid, (*hb_it).prevPhysReg, (*hb_it).instSeqNum); 926 927 freeList->addReg((*hb_it).prevPhysReg); 928 ++renameCommittedMaps; 929 930 historyBuffer[tid].erase(hb_it--); 931 } 932} 933 934template <class Impl> 935inline void 936DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst, ThreadID tid) 937{ 938 assert(renameMap[tid] != 0); 939 940 unsigned num_src_regs = inst->numSrcRegs(); 941 942 // Get the architectual register numbers from the source and 943 // destination operands, and redirect them to the right register. 944 // Will need to mark dependencies though. 945 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) { 946 RegIndex src_reg = inst->srcRegIdx(src_idx); 947 RegIndex flat_src_reg = src_reg; 948 if (src_reg < TheISA::FP_Base_DepTag) { 949 flat_src_reg = inst->tcBase()->flattenIntIndex(src_reg); 950 DPRINTF(Rename, "Flattening index %d to %d.\n", 951 (int)src_reg, (int)flat_src_reg); 952 } else if (src_reg < TheISA::Ctrl_Base_DepTag) { 953 src_reg = src_reg - TheISA::FP_Base_DepTag; 954 flat_src_reg = inst->tcBase()->flattenFloatIndex(src_reg); 955 DPRINTF(Rename, "Flattening index %d to %d.\n", 956 (int)src_reg, (int)flat_src_reg); 957 flat_src_reg += TheISA::NumIntRegs; 958 } else if (src_reg < TheISA::Max_DepTag) { 959 flat_src_reg = src_reg - TheISA::Ctrl_Base_DepTag + 960 TheISA::NumFloatRegs + TheISA::NumIntRegs; 961 DPRINTF(Rename, "Adjusting reg index from %d to %d.\n", 962 src_reg, flat_src_reg); 963 } else { 964 panic("Reg index is out of bound: %d.", src_reg); 965 } 966 967 // Look up the source registers to get the phys. register they've 968 // been renamed to, and set the sources to those registers. 969 PhysRegIndex renamed_reg = renameMap[tid]->lookup(flat_src_reg); 970 971 DPRINTF(Rename, "[tid:%u]: Looking up arch reg %i, got " 972 "physical reg %i.\n", tid, (int)flat_src_reg, 973 (int)renamed_reg); 974 975 inst->renameSrcReg(src_idx, renamed_reg); 976 977 // See if the register is ready or not. 978 if (scoreboard->getReg(renamed_reg) == true) { 979 DPRINTF(Rename, "[tid:%u]: Register %d is ready.\n", 980 tid, renamed_reg); 981 982 inst->markSrcRegReady(src_idx); 983 } else { 984 DPRINTF(Rename, "[tid:%u]: Register %d is not ready.\n", 985 tid, renamed_reg); 986 } 987 988 ++renameRenameLookups; 989 inst->isFloating() ? fpRenameLookups++ : intRenameLookups++; 990 } 991} 992 993template <class Impl> 994inline void 995DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst, ThreadID tid) 996{ 997 typename RenameMap::RenameInfo rename_result; 998 999 unsigned num_dest_regs = inst->numDestRegs(); 1000 1001 // Rename the destination registers. 1002 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) { 1003 RegIndex dest_reg = inst->destRegIdx(dest_idx); 1004 RegIndex flat_dest_reg = dest_reg; 1005 if (dest_reg < TheISA::FP_Base_DepTag) { 1006 // Integer registers are flattened. 1007 flat_dest_reg = inst->tcBase()->flattenIntIndex(dest_reg); 1008 DPRINTF(Rename, "Flattening index %d to %d.\n", 1009 (int)dest_reg, (int)flat_dest_reg); 1010 } else if (dest_reg < TheISA::Ctrl_Base_DepTag) { 1011 dest_reg = dest_reg - TheISA::FP_Base_DepTag; 1012 flat_dest_reg = inst->tcBase()->flattenFloatIndex(dest_reg); 1013 DPRINTF(Rename, "Flattening index %d to %d.\n", 1014 (int)dest_reg, (int)flat_dest_reg); 1015 flat_dest_reg += TheISA::NumIntRegs; 1016 } else if (dest_reg < TheISA::Max_DepTag) { 1017 // Floating point and Miscellaneous registers need their indexes 1018 // adjusted to account for the expanded number of flattened int regs. 1019 flat_dest_reg = dest_reg - TheISA::Ctrl_Base_DepTag + 1020 TheISA::NumIntRegs + TheISA::NumFloatRegs; 1021 DPRINTF(Rename, "Adjusting reg index from %d to %d.\n", 1022 dest_reg, flat_dest_reg); 1023 } else { 1024 panic("Reg index is out of bound: %d.", dest_reg); 1025 } 1026 1027 inst->flattenDestReg(dest_idx, flat_dest_reg); 1028 1029 // Get the physical register that the destination will be 1030 // renamed to. 1031 rename_result = renameMap[tid]->rename(flat_dest_reg); 1032 1033 //Mark Scoreboard entry as not ready 1034 if (dest_reg < TheISA::Ctrl_Base_DepTag) 1035 scoreboard->unsetReg(rename_result.first); 1036 1037 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical " 1038 "reg %i.\n", tid, (int)flat_dest_reg, 1039 (int)rename_result.first); 1040 1041 // Record the rename information so that a history can be kept. 1042 RenameHistory hb_entry(inst->seqNum, flat_dest_reg, 1043 rename_result.first, 1044 rename_result.second); 1045 1046 historyBuffer[tid].push_front(hb_entry); 1047 1048 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer " 1049 "(size=%i), [sn:%lli].\n",tid, 1050 historyBuffer[tid].size(), 1051 (*historyBuffer[tid].begin()).instSeqNum); 1052 1053 // Tell the instruction to rename the appropriate destination 1054 // register (dest_idx) to the new physical register 1055 // (rename_result.first), and record the previous physical 1056 // register that the same logical register was renamed to 1057 // (rename_result.second). 1058 inst->renameDestReg(dest_idx, 1059 rename_result.first, 1060 rename_result.second); 1061 1062 ++renameRenamedOperands; 1063 } 1064} 1065 1066template <class Impl> 1067inline int 1068DefaultRename<Impl>::calcFreeROBEntries(ThreadID tid) 1069{ 1070 int num_free = freeEntries[tid].robEntries - 1071 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched); 1072 1073 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free); 1074 1075 return num_free; 1076} 1077 1078template <class Impl> 1079inline int 1080DefaultRename<Impl>::calcFreeIQEntries(ThreadID tid) 1081{ 1082 int num_free = freeEntries[tid].iqEntries - 1083 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched); 1084 1085 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free); 1086 1087 return num_free; 1088} 1089 1090template <class Impl> 1091inline int 1092DefaultRename<Impl>::calcFreeLSQEntries(ThreadID tid) 1093{ 1094 int num_free = freeEntries[tid].lsqEntries - 1095 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ); 1096 1097 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free); 1098 1099 return num_free; 1100} 1101 1102template <class Impl> 1103unsigned 1104DefaultRename<Impl>::validInsts() 1105{ 1106 unsigned inst_count = 0; 1107 1108 for (int i=0; i<fromDecode->size; i++) { 1109 if (!fromDecode->insts[i]->isSquashed()) 1110 inst_count++; 1111 } 1112 1113 return inst_count; 1114} 1115 1116template <class Impl> 1117void 1118DefaultRename<Impl>::readStallSignals(ThreadID tid) 1119{ 1120 if (fromIEW->iewBlock[tid]) { 1121 stalls[tid].iew = true; 1122 } 1123 1124 if (fromIEW->iewUnblock[tid]) { 1125 assert(stalls[tid].iew); 1126 stalls[tid].iew = false; 1127 } 1128 1129 if (fromCommit->commitBlock[tid]) { 1130 stalls[tid].commit = true; 1131 } 1132 1133 if (fromCommit->commitUnblock[tid]) { 1134 assert(stalls[tid].commit); 1135 stalls[tid].commit = false; 1136 } 1137} 1138 1139template <class Impl> 1140bool 1141DefaultRename<Impl>::checkStall(ThreadID tid) 1142{ 1143 bool ret_val = false; 1144 1145 if (stalls[tid].iew) { 1146 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid); 1147 ret_val = true; 1148 } else if (stalls[tid].commit) { 1149 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid); 1150 ret_val = true; 1151 } else if (calcFreeROBEntries(tid) <= 0) { 1152 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid); 1153 ret_val = true; 1154 } else if (calcFreeIQEntries(tid) <= 0) { 1155 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid); 1156 ret_val = true; 1157 } else if (calcFreeLSQEntries(tid) <= 0) { 1158 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid); 1159 ret_val = true; 1160 } else if (renameMap[tid]->numFreeEntries() <= 0) { 1161 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid); 1162 ret_val = true; 1163 } else if (renameStatus[tid] == SerializeStall && 1164 (!emptyROB[tid] || instsInProgress[tid])) { 1165 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not " 1166 "empty.\n", 1167 tid); 1168 ret_val = true; 1169 } 1170 1171 return ret_val; 1172} 1173 1174template <class Impl> 1175void 1176DefaultRename<Impl>::readFreeEntries(ThreadID tid) 1177{ 1178 if (fromIEW->iewInfo[tid].usedIQ) 1179 freeEntries[tid].iqEntries = fromIEW->iewInfo[tid].freeIQEntries; 1180 1181 if (fromIEW->iewInfo[tid].usedLSQ) 1182 freeEntries[tid].lsqEntries = fromIEW->iewInfo[tid].freeLSQEntries; 1183 1184 if (fromCommit->commitInfo[tid].usedROB) { 1185 freeEntries[tid].robEntries = 1186 fromCommit->commitInfo[tid].freeROBEntries; 1187 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB; 1188 } 1189 1190 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n", 1191 tid, 1192 freeEntries[tid].iqEntries, 1193 freeEntries[tid].robEntries, 1194 freeEntries[tid].lsqEntries); 1195 1196 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n", 1197 tid, instsInProgress[tid]); 1198} 1199 1200template <class Impl> 1201bool 1202DefaultRename<Impl>::checkSignalsAndUpdate(ThreadID tid) 1203{ 1204 // Check if there's a squash signal, squash if there is 1205 // Check stall signals, block if necessary. 1206 // If status was blocked 1207 // check if stall conditions have passed 1208 // if so then go to unblocking 1209 // If status was Squashing 1210 // check if squashing is not high. Switch to running this cycle. 1211 // If status was serialize stall 1212 // check if ROB is empty and no insts are in flight to the ROB 1213 1214 readFreeEntries(tid); 1215 readStallSignals(tid); 1216 1217 if (fromCommit->commitInfo[tid].squash) { 1218 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from " 1219 "commit.\n", tid); 1220 1221 squash(fromCommit->commitInfo[tid].doneSeqNum, tid); 1222 1223 return true; 1224 } 1225 1226 if (fromCommit->commitInfo[tid].robSquashing) { 1227 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid); 1228 1229 renameStatus[tid] = Squashing; 1230 1231 return true; 1232 } 1233 1234 if (checkStall(tid)) { 1235 return block(tid); 1236 } 1237 1238 if (renameStatus[tid] == Blocked) { 1239 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n", 1240 tid); 1241 1242 renameStatus[tid] = Unblocking; 1243 1244 unblock(tid); 1245 1246 return true; 1247 } 1248 1249 if (renameStatus[tid] == Squashing) { 1250 // Switch status to running if rename isn't being told to block or 1251 // squash this cycle. 1252 if (resumeSerialize) { 1253 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to serialize.\n", 1254 tid); 1255 1256 renameStatus[tid] = SerializeStall; 1257 return true; 1258 } else if (resumeUnblocking) { 1259 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to unblocking.\n", 1260 tid); 1261 renameStatus[tid] = Unblocking; 1262 return true; 1263 } else { 1264 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n", 1265 tid); 1266 1267 renameStatus[tid] = Running; 1268 return false; 1269 } 1270 } 1271 1272 if (renameStatus[tid] == SerializeStall) { 1273 // Stall ends once the ROB is free. 1274 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to " 1275 "unblocking.\n", tid); 1276 1277 DynInstPtr serial_inst = serializeInst[tid]; 1278 1279 renameStatus[tid] = Unblocking; 1280 1281 unblock(tid); 1282 1283 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with " 1284 "PC %s.\n", tid, serial_inst->seqNum, serial_inst->pcState()); 1285 1286 // Put instruction into queue here. 1287 serial_inst->clearSerializeBefore(); 1288 1289 if (!skidBuffer[tid].empty()) { 1290 skidBuffer[tid].push_front(serial_inst); 1291 } else { 1292 insts[tid].push_front(serial_inst); 1293 } 1294 1295 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename." 1296 " Adding to front of list.\n", tid); 1297 1298 serializeInst[tid] = NULL; 1299 1300 return true; 1301 } 1302 1303 // If we've reached this point, we have not gotten any signals that 1304 // cause rename to change its status. Rename remains the same as before. 1305 return false; 1306} 1307 1308template<class Impl> 1309void 1310DefaultRename<Impl>::serializeAfter(InstQueue &inst_list, ThreadID tid) 1311{ 1312 if (inst_list.empty()) { 1313 // Mark a bit to say that I must serialize on the next instruction. 1314 serializeOnNextInst[tid] = true; 1315 return; 1316 } 1317 1318 // Set the next instruction as serializing. 1319 inst_list.front()->setSerializeBefore(); 1320} 1321 1322template <class Impl> 1323inline void 1324DefaultRename<Impl>::incrFullStat(const FullSource &source) 1325{ 1326 switch (source) { 1327 case ROB: 1328 ++renameROBFullEvents; 1329 break; 1330 case IQ: 1331 ++renameIQFullEvents; 1332 break; 1333 case LSQ: 1334 ++renameLSQFullEvents; 1335 break; 1336 default: 1337 panic("Rename full stall stat should be incremented for a reason!"); 1338 break; 1339 } 1340} 1341 1342template <class Impl> 1343void 1344DefaultRename<Impl>::dumpHistory() 1345{ 1346 typename std::list<RenameHistory>::iterator buf_it; 1347 1348 for (ThreadID tid = 0; tid < numThreads; tid++) { 1349 1350 buf_it = historyBuffer[tid].begin(); 1351 1352 while (buf_it != historyBuffer[tid].end()) { 1353 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys " 1354 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg, 1355 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg); 1356 1357 buf_it++; 1358 } 1359 } 1360} 1361