rename_impl.hh revision 3093
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 <list> 33 34#include "config/full_system.hh" 35#include "cpu/o3/rename.hh" 36 37template <class Impl> 38DefaultRename<Impl>::DefaultRename(Params *params) 39 : iewToRenameDelay(params->iewToRenameDelay), 40 decodeToRenameDelay(params->decodeToRenameDelay), 41 commitToRenameDelay(params->commitToRenameDelay), 42 renameWidth(params->renameWidth), 43 commitWidth(params->commitWidth), 44 numThreads(params->numberOfThreads) 45{ 46 _status = Inactive; 47 48 for (int i=0; i< numThreads; i++) { 49 renameStatus[i] = Idle; 50 51 freeEntries[i].iqEntries = 0; 52 freeEntries[i].lsqEntries = 0; 53 freeEntries[i].robEntries = 0; 54 55 stalls[i].iew = false; 56 stalls[i].commit = false; 57 serializeInst[i] = NULL; 58 59 instsInProgress[i] = 0; 60 61 emptyROB[i] = true; 62 63 serializeOnNextInst[i] = false; 64 } 65 66 // @todo: Make into a parameter. 67 skidBufferMax = (2 * (iewToRenameDelay * params->decodeWidth)) + renameWidth; 68} 69 70template <class Impl> 71std::string 72DefaultRename<Impl>::name() const 73{ 74 return cpu->name() + ".rename"; 75} 76 77template <class Impl> 78void 79DefaultRename<Impl>::regStats() 80{ 81 renameSquashCycles 82 .name(name() + ".RENAME:SquashCycles") 83 .desc("Number of cycles rename is squashing") 84 .prereq(renameSquashCycles); 85 renameIdleCycles 86 .name(name() + ".RENAME:IdleCycles") 87 .desc("Number of cycles rename is idle") 88 .prereq(renameIdleCycles); 89 renameBlockCycles 90 .name(name() + ".RENAME:BlockCycles") 91 .desc("Number of cycles rename is blocking") 92 .prereq(renameBlockCycles); 93 renameSerializeStallCycles 94 .name(name() + ".RENAME:serializeStallCycles") 95 .desc("count of cycles rename stalled for serializing inst") 96 .flags(Stats::total); 97 renameRunCycles 98 .name(name() + ".RENAME:RunCycles") 99 .desc("Number of cycles rename is running") 100 .prereq(renameIdleCycles); 101 renameUnblockCycles 102 .name(name() + ".RENAME:UnblockCycles") 103 .desc("Number of cycles rename is unblocking") 104 .prereq(renameUnblockCycles); 105 renameRenamedInsts 106 .name(name() + ".RENAME:RenamedInsts") 107 .desc("Number of instructions processed by rename") 108 .prereq(renameRenamedInsts); 109 renameSquashedInsts 110 .name(name() + ".RENAME:SquashedInsts") 111 .desc("Number of squashed instructions processed by rename") 112 .prereq(renameSquashedInsts); 113 renameROBFullEvents 114 .name(name() + ".RENAME:ROBFullEvents") 115 .desc("Number of times rename has blocked due to ROB full") 116 .prereq(renameROBFullEvents); 117 renameIQFullEvents 118 .name(name() + ".RENAME:IQFullEvents") 119 .desc("Number of times rename has blocked due to IQ full") 120 .prereq(renameIQFullEvents); 121 renameLSQFullEvents 122 .name(name() + ".RENAME:LSQFullEvents") 123 .desc("Number of times rename has blocked due to LSQ full") 124 .prereq(renameLSQFullEvents); 125 renameFullRegistersEvents 126 .name(name() + ".RENAME:FullRegisterEvents") 127 .desc("Number of times there has been no free registers") 128 .prereq(renameFullRegistersEvents); 129 renameRenamedOperands 130 .name(name() + ".RENAME:RenamedOperands") 131 .desc("Number of destination operands rename has renamed") 132 .prereq(renameRenamedOperands); 133 renameRenameLookups 134 .name(name() + ".RENAME:RenameLookups") 135 .desc("Number of register rename lookups that rename has made") 136 .prereq(renameRenameLookups); 137 renameCommittedMaps 138 .name(name() + ".RENAME:CommittedMaps") 139 .desc("Number of HB maps that are committed") 140 .prereq(renameCommittedMaps); 141 renameUndoneMaps 142 .name(name() + ".RENAME:UndoneMaps") 143 .desc("Number of HB maps that are undone due to squashing") 144 .prereq(renameUndoneMaps); 145 renamedSerializing 146 .name(name() + ".RENAME:serializingInsts") 147 .desc("count of serializing insts renamed") 148 .flags(Stats::total) 149 ; 150 renamedTempSerializing 151 .name(name() + ".RENAME:tempSerializingInsts") 152 .desc("count of temporary serializing insts renamed") 153 .flags(Stats::total) 154 ; 155 renameSkidInsts 156 .name(name() + ".RENAME:skidInsts") 157 .desc("count of insts added to the skid buffer") 158 .flags(Stats::total) 159 ; 160} 161 162template <class Impl> 163void 164DefaultRename<Impl>::setCPU(O3CPU *cpu_ptr) 165{ 166 DPRINTF(Rename, "Setting CPU pointer.\n"); 167 cpu = cpu_ptr; 168} 169 170template <class Impl> 171void 172DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) 173{ 174 DPRINTF(Rename, "Setting time buffer pointer.\n"); 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 DPRINTF(Rename, "Setting rename queue pointer.\n"); 192 renameQueue = rq_ptr; 193 194 // Setup wire to write information to future stages. 195 toIEW = renameQueue->getWire(0); 196} 197 198template <class Impl> 199void 200DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr) 201{ 202 DPRINTF(Rename, "Setting decode queue pointer.\n"); 203 decodeQueue = dq_ptr; 204 205 // Setup wire to get information from decode. 206 fromDecode = decodeQueue->getWire(-decodeToRenameDelay); 207} 208 209template <class Impl> 210void 211DefaultRename<Impl>::initStage() 212{ 213 // Grab the number of free entries directly from the stages. 214 for (int tid=0; tid < numThreads; tid++) { 215 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid); 216 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid); 217 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid); 218 emptyROB[tid] = true; 219 } 220} 221 222template<class Impl> 223void 224DefaultRename<Impl>::setActiveThreads(std::list<unsigned> *at_ptr) 225{ 226 DPRINTF(Rename, "Setting active threads list pointer.\n"); 227 activeThreads = at_ptr; 228} 229 230 231template <class Impl> 232void 233DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[]) 234{ 235 DPRINTF(Rename, "Setting rename map pointers.\n"); 236 237 for (int i=0; i<numThreads; i++) { 238 renameMap[i] = &rm_ptr[i]; 239 } 240} 241 242template <class Impl> 243void 244DefaultRename<Impl>::setFreeList(FreeList *fl_ptr) 245{ 246 DPRINTF(Rename, "Setting free list pointer.\n"); 247 freeList = fl_ptr; 248} 249 250template<class Impl> 251void 252DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard) 253{ 254 DPRINTF(Rename, "Setting scoreboard pointer.\n"); 255 scoreboard = _scoreboard; 256} 257 258template <class Impl> 259bool 260DefaultRename<Impl>::drain() 261{ 262 // Rename is ready to switch out at any time. 263 cpu->signalDrained(); 264 return true; 265} 266 267template <class Impl> 268void 269DefaultRename<Impl>::switchOut() 270{ 271 // Clear any state, fix up the rename map. 272 for (int i = 0; i < numThreads; i++) { 273 typename std::list<RenameHistory>::iterator hb_it = 274 historyBuffer[i].begin(); 275 276 while (!historyBuffer[i].empty()) { 277 assert(hb_it != historyBuffer[i].end()); 278 279 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence " 280 "number %i.\n", i, (*hb_it).instSeqNum); 281 282 // Tell the rename map to set the architected register to the 283 // previous physical register that it was renamed to. 284 renameMap[i]->setEntry(hb_it->archReg, hb_it->prevPhysReg); 285 286 // Put the renamed physical register back on the free list. 287 freeList->addReg(hb_it->newPhysReg); 288 289 historyBuffer[i].erase(hb_it++); 290 } 291 insts[i].clear(); 292 skidBuffer[i].clear(); 293 } 294} 295 296template <class Impl> 297void 298DefaultRename<Impl>::takeOverFrom() 299{ 300 _status = Inactive; 301 initStage(); 302 303 // Reset all state prior to taking over from the other CPU. 304 for (int i=0; i< numThreads; i++) { 305 renameStatus[i] = Idle; 306 307 stalls[i].iew = false; 308 stalls[i].commit = false; 309 serializeInst[i] = NULL; 310 311 instsInProgress[i] = 0; 312 313 emptyROB[i] = true; 314 315 serializeOnNextInst[i] = false; 316 } 317} 318 319template <class Impl> 320void 321DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, unsigned tid) 322{ 323 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid); 324 325 // Clear the stall signal if rename was blocked or unblocking before. 326 // If it still needs to block, the blocking should happen the next 327 // cycle and there should be space to hold everything due to the squash. 328 if (renameStatus[tid] == Blocked || 329 renameStatus[tid] == Unblocking || 330 renameStatus[tid] == SerializeStall) { 331 332 toDecode->renameUnblock[tid] = 1; 333 334 serializeInst[tid] = NULL; 335 } 336 337 // Set the status to Squashing. 338 renameStatus[tid] = Squashing; 339 340 // Squash any instructions from decode. 341 unsigned squashCount = 0; 342 343 for (int i=0; i<fromDecode->size; i++) { 344 if (fromDecode->insts[i]->threadNumber == tid && 345 fromDecode->insts[i]->seqNum > squash_seq_num) { 346 fromDecode->insts[i]->setSquashed(); 347 wroteToTimeBuffer = true; 348 squashCount++; 349 } 350 351 } 352 353 // Clear the instruction list and skid buffer in case they have any 354 // insts in them. Since we support multiple ISAs, we cant just: 355 // "insts[tid].clear();" or "skidBuffer[tid].clear()" since there is 356 // a possible delay slot inst for different architectures 357 // insts[tid].clear(); 358#if ISA_HAS_DELAY_SLOT 359 DPRINTF(Rename, "[tid:%i] Squashing incoming decode instructions until " 360 "[sn:%i].\n",tid, squash_seq_num); 361 ListIt ilist_it = insts[tid].begin(); 362 while (ilist_it != insts[tid].end()) { 363 if ((*ilist_it)->seqNum > squash_seq_num) { 364 (*ilist_it)->setSquashed(); 365 DPRINTF(Rename, "Squashing incoming decode instruction, " 366 "[tid:%i] [sn:%i] PC %08p.\n", tid, (*ilist_it)->seqNum, (*ilist_it)->PC); 367 } 368 ilist_it++; 369 } 370#else 371 insts[tid].clear(); 372#endif 373 374 // Clear the skid buffer in case it has any data in it. 375 // See comments above. 376 // skidBuffer[tid].clear(); 377#if ISA_HAS_DELAY_SLOT 378 DPRINTF(Rename, "[tid:%i] Squashing incoming skidbuffer instructions " 379 "until [sn:%i].\n", tid, squash_seq_num); 380 ListIt slist_it = skidBuffer[tid].begin(); 381 while (slist_it != skidBuffer[tid].end()) { 382 if ((*slist_it)->seqNum > squash_seq_num) { 383 (*slist_it)->setSquashed(); 384 DPRINTF(Rename, "Squashing skidbuffer instruction, [tid:%i] [sn:%i]" 385 "PC %08p.\n", tid, (*slist_it)->seqNum, (*slist_it)->PC); 386 } 387 slist_it++; 388 } 389#else 390 skidBuffer[tid].clear(); 391#endif 392 doSquash(squash_seq_num, tid); 393} 394 395template <class Impl> 396void 397DefaultRename<Impl>::tick() 398{ 399 wroteToTimeBuffer = false; 400 401 blockThisCycle = false; 402 403 bool status_change = false; 404 405 toIEWIndex = 0; 406 407 sortInsts(); 408 409 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 410 411 // Check stall and squash signals. 412 while (threads != (*activeThreads).end()) { 413 unsigned tid = *threads++; 414 415 DPRINTF(Rename, "Processing [tid:%i]\n", tid); 416 417 status_change = checkSignalsAndUpdate(tid) || status_change; 418 419 rename(status_change, tid); 420 } 421 422 if (status_change) { 423 updateStatus(); 424 } 425 426 if (wroteToTimeBuffer) { 427 DPRINTF(Activity, "Activity this cycle.\n"); 428 cpu->activityThisCycle(); 429 } 430 431 threads = (*activeThreads).begin(); 432 433 while (threads != (*activeThreads).end()) { 434 unsigned tid = *threads++; 435 436 // If we committed this cycle then doneSeqNum will be > 0 437 if (fromCommit->commitInfo[tid].doneSeqNum != 0 && 438 !fromCommit->commitInfo[tid].squash && 439 renameStatus[tid] != Squashing) { 440 441 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum, 442 tid); 443 } 444 } 445 446 // @todo: make into updateProgress function 447 for (int tid=0; tid < numThreads; tid++) { 448 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched; 449 450 assert(instsInProgress[tid] >=0); 451 } 452 453} 454 455template<class Impl> 456void 457DefaultRename<Impl>::rename(bool &status_change, unsigned tid) 458{ 459 // If status is Running or idle, 460 // call renameInsts() 461 // If status is Unblocking, 462 // buffer any instructions coming from decode 463 // continue trying to empty skid buffer 464 // check if stall conditions have passed 465 466 if (renameStatus[tid] == Blocked) { 467 ++renameBlockCycles; 468 } else if (renameStatus[tid] == Squashing) { 469 ++renameSquashCycles; 470 } else if (renameStatus[tid] == SerializeStall) { 471 ++renameSerializeStallCycles; 472 } 473 474 if (renameStatus[tid] == Running || 475 renameStatus[tid] == Idle) { 476 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run " 477 "stage.\n", tid); 478 479 renameInsts(tid); 480 } else if (renameStatus[tid] == Unblocking) { 481 renameInsts(tid); 482 483 if (validInsts()) { 484 // Add the current inputs to the skid buffer so they can be 485 // reprocessed when this stage unblocks. 486 skidInsert(tid); 487 } 488 489 // If we switched over to blocking, then there's a potential for 490 // an overall status change. 491 status_change = unblock(tid) || status_change || blockThisCycle; 492 } 493} 494 495template <class Impl> 496void 497DefaultRename<Impl>::renameInsts(unsigned tid) 498{ 499 // Instructions can be either in the skid buffer or the queue of 500 // instructions coming from decode, depending on the status. 501 int insts_available = renameStatus[tid] == Unblocking ? 502 skidBuffer[tid].size() : insts[tid].size(); 503 504 // Check the decode queue to see if instructions are available. 505 // If there are no available instructions to rename, then do nothing. 506 if (insts_available == 0) { 507 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n", 508 tid); 509 // Should I change status to idle? 510 ++renameIdleCycles; 511 return; 512 } else if (renameStatus[tid] == Unblocking) { 513 ++renameUnblockCycles; 514 } else if (renameStatus[tid] == Running) { 515 ++renameRunCycles; 516 } 517 518 DynInstPtr inst; 519 520 // Will have to do a different calculation for the number of free 521 // entries. 522 int free_rob_entries = calcFreeROBEntries(tid); 523 int free_iq_entries = calcFreeIQEntries(tid); 524 int free_lsq_entries = calcFreeLSQEntries(tid); 525 int min_free_entries = free_rob_entries; 526 527 FullSource source = ROB; 528 529 if (free_iq_entries < min_free_entries) { 530 min_free_entries = free_iq_entries; 531 source = IQ; 532 } 533 534 if (free_lsq_entries < min_free_entries) { 535 min_free_entries = free_lsq_entries; 536 source = LSQ; 537 } 538 539 // Check if there's any space left. 540 if (min_free_entries <= 0) { 541 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ " 542 "entries.\n" 543 "ROB has %i free entries.\n" 544 "IQ has %i free entries.\n" 545 "LSQ has %i free entries.\n", 546 tid, 547 free_rob_entries, 548 free_iq_entries, 549 free_lsq_entries); 550 551 blockThisCycle = true; 552 553 block(tid); 554 555 incrFullStat(source); 556 557 return; 558 } else if (min_free_entries < insts_available) { 559 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle." 560 "%i insts available, but only %i insts can be " 561 "renamed due to ROB/IQ/LSQ limits.\n", 562 tid, insts_available, min_free_entries); 563 564 insts_available = min_free_entries; 565 566 blockThisCycle = true; 567 568 incrFullStat(source); 569 } 570 571 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ? 572 skidBuffer[tid] : insts[tid]; 573 574 DPRINTF(Rename, "[tid:%u]: %i available instructions to " 575 "send iew.\n", tid, insts_available); 576 577 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts " 578 "dispatched to IQ last cycle.\n", 579 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched); 580 581 // Handle serializing the next instruction if necessary. 582 if (serializeOnNextInst[tid]) { 583 if (emptyROB[tid] && instsInProgress[tid] == 0) { 584 // ROB already empty; no need to serialize. 585 serializeOnNextInst[tid] = false; 586 } else if (!insts_to_rename.empty()) { 587 insts_to_rename.front()->setSerializeBefore(); 588 } 589 } 590 591 int renamed_insts = 0; 592 593 while (insts_available > 0 && toIEWIndex < renameWidth) { 594 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid); 595 596 assert(!insts_to_rename.empty()); 597 598 inst = insts_to_rename.front(); 599 600 insts_to_rename.pop_front(); 601 602 if (renameStatus[tid] == Unblocking) { 603 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%#x from rename " 604 "skidBuffer\n", 605 tid, inst->seqNum, inst->readPC()); 606 } 607 608 if (inst->isSquashed()) { 609 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %#x is " 610 "squashed, skipping.\n", 611 tid, inst->seqNum, inst->readPC()); 612 613 ++renameSquashedInsts; 614 615 // Decrement how many instructions are available. 616 --insts_available; 617 618 continue; 619 } 620 621 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with " 622 "PC %#x.\n", 623 tid, inst->seqNum, inst->readPC()); 624 625 // Handle serializeAfter/serializeBefore instructions. 626 // serializeAfter marks the next instruction as serializeBefore. 627 // serializeBefore makes the instruction wait in rename until the ROB 628 // is empty. 629 630 // In this model, IPR accesses are serialize before 631 // instructions, and store conditionals are serialize after 632 // instructions. This is mainly due to lack of support for 633 // out-of-order operations of either of those classes of 634 // instructions. 635 if ((inst->isIprAccess() || inst->isSerializeBefore()) && 636 !inst->isSerializeHandled()) { 637 DPRINTF(Rename, "Serialize before instruction encountered.\n"); 638 639 if (!inst->isTempSerializeBefore()) { 640 renamedSerializing++; 641 inst->setSerializeHandled(); 642 } else { 643 renamedTempSerializing++; 644 } 645 646 // Change status over to SerializeStall so that other stages know 647 // what this is blocked on. 648 renameStatus[tid] = SerializeStall; 649 650 serializeInst[tid] = inst; 651 652 blockThisCycle = true; 653 654 break; 655 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) && 656 !inst->isSerializeHandled()) { 657 DPRINTF(Rename, "Serialize after instruction encountered.\n"); 658 659 renamedSerializing++; 660 661 inst->setSerializeHandled(); 662 663 serializeAfter(insts_to_rename, tid); 664 } 665 666 // Check here to make sure there are enough destination registers 667 // to rename to. Otherwise block. 668 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) { 669 DPRINTF(Rename, "Blocking due to lack of free " 670 "physical registers to rename to.\n"); 671 blockThisCycle = true; 672 673 ++renameFullRegistersEvents; 674 675 break; 676 } 677 678 renameSrcRegs(inst, inst->threadNumber); 679 680 renameDestRegs(inst, inst->threadNumber); 681 682 ++renamed_insts; 683 684 // Put instruction in rename queue. 685 toIEW->insts[toIEWIndex] = inst; 686 ++(toIEW->size); 687 688 // Increment which instruction we're on. 689 ++toIEWIndex; 690 691 // Decrement how many instructions are available. 692 --insts_available; 693 } 694 695 instsInProgress[tid] += renamed_insts; 696 renameRenamedInsts += renamed_insts; 697 698 // If we wrote to the time buffer, record this. 699 if (toIEWIndex) { 700 wroteToTimeBuffer = true; 701 } 702 703 // Check if there's any instructions left that haven't yet been renamed. 704 // If so then block. 705 if (insts_available) { 706 blockThisCycle = true; 707 } 708 709 if (blockThisCycle) { 710 block(tid); 711 toDecode->renameUnblock[tid] = false; 712 } 713} 714 715template<class Impl> 716void 717DefaultRename<Impl>::skidInsert(unsigned tid) 718{ 719 DynInstPtr inst = NULL; 720 721 while (!insts[tid].empty()) { 722 inst = insts[tid].front(); 723 724 insts[tid].pop_front(); 725 726 assert(tid == inst->threadNumber); 727 728 DPRINTF(Rename, "[tid:%u]: Inserting [sn:%lli] PC:%#x into Rename " 729 "skidBuffer\n", tid, inst->seqNum, inst->readPC()); 730 731 ++renameSkidInsts; 732 733 skidBuffer[tid].push_back(inst); 734 } 735 736 if (skidBuffer[tid].size() > skidBufferMax) 737 panic("Skidbuffer Exceeded Max Size"); 738} 739 740template <class Impl> 741void 742DefaultRename<Impl>::sortInsts() 743{ 744 int insts_from_decode = fromDecode->size; 745#ifdef DEBUG 746#if !ISA_HAS_DELAY_SLOT 747 for (int i=0; i < numThreads; i++) 748 assert(insts[i].empty()); 749#endif 750#endif 751 for (int i = 0; i < insts_from_decode; ++i) { 752 DynInstPtr inst = fromDecode->insts[i]; 753 insts[inst->threadNumber].push_back(inst); 754 } 755} 756 757template<class Impl> 758bool 759DefaultRename<Impl>::skidsEmpty() 760{ 761 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 762 763 while (threads != (*activeThreads).end()) { 764 if (!skidBuffer[*threads++].empty()) 765 return false; 766 } 767 768 return true; 769} 770 771template<class Impl> 772void 773DefaultRename<Impl>::updateStatus() 774{ 775 bool any_unblocking = false; 776 777 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 778 779 threads = (*activeThreads).begin(); 780 781 while (threads != (*activeThreads).end()) { 782 unsigned tid = *threads++; 783 784 if (renameStatus[tid] == Unblocking) { 785 any_unblocking = true; 786 break; 787 } 788 } 789 790 // Rename will have activity if it's unblocking. 791 if (any_unblocking) { 792 if (_status == Inactive) { 793 _status = Active; 794 795 DPRINTF(Activity, "Activating stage.\n"); 796 797 cpu->activateStage(O3CPU::RenameIdx); 798 } 799 } else { 800 // If it's not unblocking, then rename will not have any internal 801 // activity. Switch it to inactive. 802 if (_status == Active) { 803 _status = Inactive; 804 DPRINTF(Activity, "Deactivating stage.\n"); 805 806 cpu->deactivateStage(O3CPU::RenameIdx); 807 } 808 } 809} 810 811template <class Impl> 812bool 813DefaultRename<Impl>::block(unsigned tid) 814{ 815 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid); 816 817 // Add the current inputs onto the skid buffer, so they can be 818 // reprocessed when this stage unblocks. 819 skidInsert(tid); 820 821 // Only signal backwards to block if the previous stages do not think 822 // rename is already blocked. 823 if (renameStatus[tid] != Blocked) { 824 if (renameStatus[tid] != Unblocking) { 825 toDecode->renameBlock[tid] = true; 826 toDecode->renameUnblock[tid] = false; 827 wroteToTimeBuffer = true; 828 } 829 830 // Rename can not go from SerializeStall to Blocked, otherwise 831 // it would not know to complete the serialize stall. 832 if (renameStatus[tid] != SerializeStall) { 833 // Set status to Blocked. 834 renameStatus[tid] = Blocked; 835 return true; 836 } 837 } 838 839 return false; 840} 841 842template <class Impl> 843bool 844DefaultRename<Impl>::unblock(unsigned tid) 845{ 846 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid); 847 848 // Rename is done unblocking if the skid buffer is empty. 849 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) { 850 851 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid); 852 853 toDecode->renameUnblock[tid] = true; 854 wroteToTimeBuffer = true; 855 856 renameStatus[tid] = Running; 857 return true; 858 } 859 860 return false; 861} 862 863template <class Impl> 864void 865DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, unsigned tid) 866{ 867 typename std::list<RenameHistory>::iterator hb_it = 868 historyBuffer[tid].begin(); 869 870 // After a syscall squashes everything, the history buffer may be empty 871 // but the ROB may still be squashing instructions. 872 if (historyBuffer[tid].empty()) { 873 return; 874 } 875 876 // Go through the most recent instructions, undoing the mappings 877 // they did and freeing up the registers. 878 while (!historyBuffer[tid].empty() && 879 (*hb_it).instSeqNum > squashed_seq_num) { 880 assert(hb_it != historyBuffer[tid].end()); 881 882 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence " 883 "number %i.\n", tid, (*hb_it).instSeqNum); 884 885 // Tell the rename map to set the architected register to the 886 // previous physical register that it was renamed to. 887 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg); 888 889 // Put the renamed physical register back on the free list. 890 freeList->addReg(hb_it->newPhysReg); 891 892 historyBuffer[tid].erase(hb_it++); 893 894 ++renameUndoneMaps; 895 } 896} 897 898template<class Impl> 899void 900DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, unsigned tid) 901{ 902 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the " 903 "history buffer %u (size=%i), until [sn:%lli].\n", 904 tid, tid, historyBuffer[tid].size(), inst_seq_num); 905 906 typename std::list<RenameHistory>::iterator hb_it = 907 historyBuffer[tid].end(); 908 909 --hb_it; 910 911 if (historyBuffer[tid].empty()) { 912 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid); 913 return; 914 } else if (hb_it->instSeqNum > inst_seq_num) { 915 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure " 916 "that a syscall happened recently.\n", tid); 917 return; 918 } 919 920 // Commit all the renames up until (and including) the committed sequence 921 // number. Some or even all of the committed instructions may not have 922 // rename histories if they did not have destination registers that were 923 // renamed. 924 while (!historyBuffer[tid].empty() && 925 hb_it != historyBuffer[tid].end() && 926 (*hb_it).instSeqNum <= inst_seq_num) { 927 928 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, " 929 "[sn:%lli].\n", 930 tid, (*hb_it).prevPhysReg, (*hb_it).instSeqNum); 931 932 freeList->addReg((*hb_it).prevPhysReg); 933 ++renameCommittedMaps; 934 935 historyBuffer[tid].erase(hb_it--); 936 } 937} 938 939template <class Impl> 940inline void 941DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst,unsigned tid) 942{ 943 assert(renameMap[tid] != 0); 944 945 unsigned num_src_regs = inst->numSrcRegs(); 946 947 // Get the architectual register numbers from the source and 948 // destination operands, and redirect them to the right register. 949 // Will need to mark dependencies though. 950 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) { 951 RegIndex src_reg = inst->srcRegIdx(src_idx); 952 953 // Look up the source registers to get the phys. register they've 954 // been renamed to, and set the sources to those registers. 955 PhysRegIndex renamed_reg = renameMap[tid]->lookup(src_reg); 956 957 DPRINTF(Rename, "[tid:%u]: Looking up arch reg %i, got " 958 "physical reg %i.\n", tid, (int)src_reg, 959 (int)renamed_reg); 960 961 inst->renameSrcReg(src_idx, renamed_reg); 962 963 // See if the register is ready or not. 964 if (scoreboard->getReg(renamed_reg) == true) { 965 DPRINTF(Rename, "[tid:%u]: Register is ready.\n", tid); 966 967 inst->markSrcRegReady(src_idx); 968 } 969 970 ++renameRenameLookups; 971 } 972} 973 974template <class Impl> 975inline void 976DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst,unsigned tid) 977{ 978 typename RenameMap::RenameInfo rename_result; 979 980 unsigned num_dest_regs = inst->numDestRegs(); 981 982 // Rename the destination registers. 983 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) { 984 RegIndex dest_reg = inst->destRegIdx(dest_idx); 985 986 // Get the physical register that the destination will be 987 // renamed to. 988 rename_result = renameMap[tid]->rename(dest_reg); 989 990 //Mark Scoreboard entry as not ready 991 scoreboard->unsetReg(rename_result.first); 992 993 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical " 994 "reg %i.\n", tid, (int)dest_reg, 995 (int)rename_result.first); 996 997 // Record the rename information so that a history can be kept. 998 RenameHistory hb_entry(inst->seqNum, dest_reg, 999 rename_result.first, 1000 rename_result.second); 1001 1002 historyBuffer[tid].push_front(hb_entry); 1003 1004 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer " 1005 "(size=%i), [sn:%lli].\n",tid, 1006 historyBuffer[tid].size(), 1007 (*historyBuffer[tid].begin()).instSeqNum); 1008 1009 // Tell the instruction to rename the appropriate destination 1010 // register (dest_idx) to the new physical register 1011 // (rename_result.first), and record the previous physical 1012 // register that the same logical register was renamed to 1013 // (rename_result.second). 1014 inst->renameDestReg(dest_idx, 1015 rename_result.first, 1016 rename_result.second); 1017 1018 ++renameRenamedOperands; 1019 } 1020} 1021 1022template <class Impl> 1023inline int 1024DefaultRename<Impl>::calcFreeROBEntries(unsigned tid) 1025{ 1026 int num_free = freeEntries[tid].robEntries - 1027 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched); 1028 1029 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free); 1030 1031 return num_free; 1032} 1033 1034template <class Impl> 1035inline int 1036DefaultRename<Impl>::calcFreeIQEntries(unsigned tid) 1037{ 1038 int num_free = freeEntries[tid].iqEntries - 1039 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched); 1040 1041 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free); 1042 1043 return num_free; 1044} 1045 1046template <class Impl> 1047inline int 1048DefaultRename<Impl>::calcFreeLSQEntries(unsigned tid) 1049{ 1050 int num_free = freeEntries[tid].lsqEntries - 1051 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ); 1052 1053 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free); 1054 1055 return num_free; 1056} 1057 1058template <class Impl> 1059unsigned 1060DefaultRename<Impl>::validInsts() 1061{ 1062 unsigned inst_count = 0; 1063 1064 for (int i=0; i<fromDecode->size; i++) { 1065 if (!fromDecode->insts[i]->isSquashed()) 1066 inst_count++; 1067 } 1068 1069 return inst_count; 1070} 1071 1072template <class Impl> 1073void 1074DefaultRename<Impl>::readStallSignals(unsigned tid) 1075{ 1076 if (fromIEW->iewBlock[tid]) { 1077 stalls[tid].iew = true; 1078 } 1079 1080 if (fromIEW->iewUnblock[tid]) { 1081 assert(stalls[tid].iew); 1082 stalls[tid].iew = false; 1083 } 1084 1085 if (fromCommit->commitBlock[tid]) { 1086 stalls[tid].commit = true; 1087 } 1088 1089 if (fromCommit->commitUnblock[tid]) { 1090 assert(stalls[tid].commit); 1091 stalls[tid].commit = false; 1092 } 1093} 1094 1095template <class Impl> 1096bool 1097DefaultRename<Impl>::checkStall(unsigned tid) 1098{ 1099 bool ret_val = false; 1100 1101 if (stalls[tid].iew) { 1102 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid); 1103 ret_val = true; 1104 } else if (stalls[tid].commit) { 1105 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid); 1106 ret_val = true; 1107 } else if (calcFreeROBEntries(tid) <= 0) { 1108 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid); 1109 ret_val = true; 1110 } else if (calcFreeIQEntries(tid) <= 0) { 1111 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid); 1112 ret_val = true; 1113 } else if (calcFreeLSQEntries(tid) <= 0) { 1114 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid); 1115 ret_val = true; 1116 } else if (renameMap[tid]->numFreeEntries() <= 0) { 1117 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid); 1118 ret_val = true; 1119 } else if (renameStatus[tid] == SerializeStall && 1120 (!emptyROB[tid] || instsInProgress[tid])) { 1121 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not " 1122 "empty.\n", 1123 tid); 1124 ret_val = true; 1125 } 1126 1127 return ret_val; 1128} 1129 1130template <class Impl> 1131void 1132DefaultRename<Impl>::readFreeEntries(unsigned tid) 1133{ 1134 bool updated = false; 1135 if (fromIEW->iewInfo[tid].usedIQ) { 1136 freeEntries[tid].iqEntries = 1137 fromIEW->iewInfo[tid].freeIQEntries; 1138 updated = true; 1139 } 1140 1141 if (fromIEW->iewInfo[tid].usedLSQ) { 1142 freeEntries[tid].lsqEntries = 1143 fromIEW->iewInfo[tid].freeLSQEntries; 1144 updated = true; 1145 } 1146 1147 if (fromCommit->commitInfo[tid].usedROB) { 1148 freeEntries[tid].robEntries = 1149 fromCommit->commitInfo[tid].freeROBEntries; 1150 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB; 1151 updated = true; 1152 } 1153 1154 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n", 1155 tid, 1156 freeEntries[tid].iqEntries, 1157 freeEntries[tid].robEntries, 1158 freeEntries[tid].lsqEntries); 1159 1160 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n", 1161 tid, instsInProgress[tid]); 1162} 1163 1164template <class Impl> 1165bool 1166DefaultRename<Impl>::checkSignalsAndUpdate(unsigned tid) 1167{ 1168 // Check if there's a squash signal, squash if there is 1169 // Check stall signals, block if necessary. 1170 // If status was blocked 1171 // check if stall conditions have passed 1172 // if so then go to unblocking 1173 // If status was Squashing 1174 // check if squashing is not high. Switch to running this cycle. 1175 // If status was serialize stall 1176 // check if ROB is empty and no insts are in flight to the ROB 1177 1178 readFreeEntries(tid); 1179 readStallSignals(tid); 1180 1181 if (fromCommit->commitInfo[tid].squash) { 1182 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from " 1183 "commit.\n", tid); 1184 1185#if ISA_HAS_DELAY_SLOT 1186 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].bdelayDoneSeqNum; 1187#else 1188 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].doneSeqNum; 1189#endif 1190 1191 squash(squashed_seq_num, tid); 1192 1193 return true; 1194 } 1195 1196 if (fromCommit->commitInfo[tid].robSquashing) { 1197 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid); 1198 1199 renameStatus[tid] = Squashing; 1200 1201 return true; 1202 } 1203 1204 if (checkStall(tid)) { 1205 return block(tid); 1206 } 1207 1208 if (renameStatus[tid] == Blocked) { 1209 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n", 1210 tid); 1211 1212 renameStatus[tid] = Unblocking; 1213 1214 unblock(tid); 1215 1216 return true; 1217 } 1218 1219 if (renameStatus[tid] == Squashing) { 1220 // Switch status to running if rename isn't being told to block or 1221 // squash this cycle. 1222 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n", 1223 tid); 1224 1225 renameStatus[tid] = Running; 1226 1227 return false; 1228 } 1229 1230 if (renameStatus[tid] == SerializeStall) { 1231 // Stall ends once the ROB is free. 1232 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to " 1233 "unblocking.\n", tid); 1234 1235 DynInstPtr serial_inst = serializeInst[tid]; 1236 1237 renameStatus[tid] = Unblocking; 1238 1239 unblock(tid); 1240 1241 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with " 1242 "PC %#x.\n", 1243 tid, serial_inst->seqNum, serial_inst->readPC()); 1244 1245 // Put instruction into queue here. 1246 serial_inst->clearSerializeBefore(); 1247 1248 if (!skidBuffer[tid].empty()) { 1249 skidBuffer[tid].push_front(serial_inst); 1250 } else { 1251 insts[tid].push_front(serial_inst); 1252 } 1253 1254 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename." 1255 " Adding to front of list.\n", tid); 1256 1257 serializeInst[tid] = NULL; 1258 1259 return true; 1260 } 1261 1262 // If we've reached this point, we have not gotten any signals that 1263 // cause rename to change its status. Rename remains the same as before. 1264 return false; 1265} 1266 1267template<class Impl> 1268void 1269DefaultRename<Impl>::serializeAfter(InstQueue &inst_list, 1270 unsigned tid) 1271{ 1272 if (inst_list.empty()) { 1273 // Mark a bit to say that I must serialize on the next instruction. 1274 serializeOnNextInst[tid] = true; 1275 return; 1276 } 1277 1278 // Set the next instruction as serializing. 1279 inst_list.front()->setSerializeBefore(); 1280} 1281 1282template <class Impl> 1283inline void 1284DefaultRename<Impl>::incrFullStat(const FullSource &source) 1285{ 1286 switch (source) { 1287 case ROB: 1288 ++renameROBFullEvents; 1289 break; 1290 case IQ: 1291 ++renameIQFullEvents; 1292 break; 1293 case LSQ: 1294 ++renameLSQFullEvents; 1295 break; 1296 default: 1297 panic("Rename full stall stat should be incremented for a reason!"); 1298 break; 1299 } 1300} 1301 1302template <class Impl> 1303void 1304DefaultRename<Impl>::dumpHistory() 1305{ 1306 typename std::list<RenameHistory>::iterator buf_it; 1307 1308 for (int i = 0; i < numThreads; i++) { 1309 1310 buf_it = historyBuffer[i].begin(); 1311 1312 while (buf_it != historyBuffer[i].end()) { 1313 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys " 1314 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg, 1315 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg); 1316 1317 buf_it++; 1318 } 1319 } 1320} 1321