inst_queue_impl.hh revision 4318
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 <limits> 33#include <vector> 34 35#include "sim/core.hh" 36 37#include "cpu/o3/fu_pool.hh" 38#include "cpu/o3/inst_queue.hh" 39 40template <class Impl> 41InstructionQueue<Impl>::FUCompletion::FUCompletion(DynInstPtr &_inst, 42 int fu_idx, 43 InstructionQueue<Impl> *iq_ptr) 44 : Event(&mainEventQueue, Stat_Event_Pri), 45 inst(_inst), fuIdx(fu_idx), iqPtr(iq_ptr), freeFU(false) 46{ 47 this->setFlags(Event::AutoDelete); 48} 49 50template <class Impl> 51void 52InstructionQueue<Impl>::FUCompletion::process() 53{ 54 iqPtr->processFUCompletion(inst, freeFU ? fuIdx : -1); 55 inst = NULL; 56} 57 58 59template <class Impl> 60const char * 61InstructionQueue<Impl>::FUCompletion::description() 62{ 63 return "Functional unit completion event"; 64} 65 66template <class Impl> 67InstructionQueue<Impl>::InstructionQueue(Params *params) 68 : fuPool(params->fuPool), 69 numEntries(params->numIQEntries), 70 totalWidth(params->issueWidth), 71 numPhysIntRegs(params->numPhysIntRegs), 72 numPhysFloatRegs(params->numPhysFloatRegs), 73 commitToIEWDelay(params->commitToIEWDelay) 74{ 75 assert(fuPool); 76 77 switchedOut = false; 78 79 numThreads = params->numberOfThreads; 80 81 // Set the number of physical registers as the number of int + float 82 numPhysRegs = numPhysIntRegs + numPhysFloatRegs; 83 84 //Create an entry for each physical register within the 85 //dependency graph. 86 dependGraph.resize(numPhysRegs); 87 88 // Resize the register scoreboard. 89 regScoreboard.resize(numPhysRegs); 90 91 //Initialize Mem Dependence Units 92 for (int i = 0; i < numThreads; i++) { 93 memDepUnit[i].init(params,i); 94 memDepUnit[i].setIQ(this); 95 } 96 97 resetState(); 98 99 std::string policy = params->smtIQPolicy; 100 101 //Convert string to lowercase 102 std::transform(policy.begin(), policy.end(), policy.begin(), 103 (int(*)(int)) tolower); 104 105 //Figure out resource sharing policy 106 if (policy == "dynamic") { 107 iqPolicy = Dynamic; 108 109 //Set Max Entries to Total ROB Capacity 110 for (int i = 0; i < numThreads; i++) { 111 maxEntries[i] = numEntries; 112 } 113 114 } else if (policy == "partitioned") { 115 iqPolicy = Partitioned; 116 117 //@todo:make work if part_amt doesnt divide evenly. 118 int part_amt = numEntries / numThreads; 119 120 //Divide ROB up evenly 121 for (int i = 0; i < numThreads; i++) { 122 maxEntries[i] = part_amt; 123 } 124 125/* 126 DPRINTF(IQ, "IQ sharing policy set to Partitioned:" 127 "%i entries per thread.\n",part_amt); 128*/ 129 130 } else if (policy == "threshold") { 131 iqPolicy = Threshold; 132 133 double threshold = (double)params->smtIQThreshold / 100; 134 135 int thresholdIQ = (int)((double)threshold * numEntries); 136 137 //Divide up by threshold amount 138 for (int i = 0; i < numThreads; i++) { 139 maxEntries[i] = thresholdIQ; 140 } 141 142/* 143 DPRINTF(IQ, "IQ sharing policy set to Threshold:" 144 "%i entries per thread.\n",thresholdIQ); 145*/ 146 } else { 147 assert(0 && "Invalid IQ Sharing Policy.Options Are:{Dynamic," 148 "Partitioned, Threshold}"); 149 } 150} 151 152template <class Impl> 153InstructionQueue<Impl>::~InstructionQueue() 154{ 155 dependGraph.reset(); 156#ifdef DEBUG 157 cprintf("Nodes traversed: %i, removed: %i\n", 158 dependGraph.nodesTraversed, dependGraph.nodesRemoved); 159#endif 160} 161 162template <class Impl> 163std::string 164InstructionQueue<Impl>::name() const 165{ 166 return cpu->name() + ".iq"; 167} 168 169template <class Impl> 170void 171InstructionQueue<Impl>::regStats() 172{ 173 using namespace Stats; 174 iqInstsAdded 175 .name(name() + ".iqInstsAdded") 176 .desc("Number of instructions added to the IQ (excludes non-spec)") 177 .prereq(iqInstsAdded); 178 179 iqNonSpecInstsAdded 180 .name(name() + ".iqNonSpecInstsAdded") 181 .desc("Number of non-speculative instructions added to the IQ") 182 .prereq(iqNonSpecInstsAdded); 183 184 iqInstsIssued 185 .name(name() + ".iqInstsIssued") 186 .desc("Number of instructions issued") 187 .prereq(iqInstsIssued); 188 189 iqIntInstsIssued 190 .name(name() + ".iqIntInstsIssued") 191 .desc("Number of integer instructions issued") 192 .prereq(iqIntInstsIssued); 193 194 iqFloatInstsIssued 195 .name(name() + ".iqFloatInstsIssued") 196 .desc("Number of float instructions issued") 197 .prereq(iqFloatInstsIssued); 198 199 iqBranchInstsIssued 200 .name(name() + ".iqBranchInstsIssued") 201 .desc("Number of branch instructions issued") 202 .prereq(iqBranchInstsIssued); 203 204 iqMemInstsIssued 205 .name(name() + ".iqMemInstsIssued") 206 .desc("Number of memory instructions issued") 207 .prereq(iqMemInstsIssued); 208 209 iqMiscInstsIssued 210 .name(name() + ".iqMiscInstsIssued") 211 .desc("Number of miscellaneous instructions issued") 212 .prereq(iqMiscInstsIssued); 213 214 iqSquashedInstsIssued 215 .name(name() + ".iqSquashedInstsIssued") 216 .desc("Number of squashed instructions issued") 217 .prereq(iqSquashedInstsIssued); 218 219 iqSquashedInstsExamined 220 .name(name() + ".iqSquashedInstsExamined") 221 .desc("Number of squashed instructions iterated over during squash;" 222 " mainly for profiling") 223 .prereq(iqSquashedInstsExamined); 224 225 iqSquashedOperandsExamined 226 .name(name() + ".iqSquashedOperandsExamined") 227 .desc("Number of squashed operands that are examined and possibly " 228 "removed from graph") 229 .prereq(iqSquashedOperandsExamined); 230 231 iqSquashedNonSpecRemoved 232 .name(name() + ".iqSquashedNonSpecRemoved") 233 .desc("Number of squashed non-spec instructions that were removed") 234 .prereq(iqSquashedNonSpecRemoved); 235/* 236 queueResDist 237 .init(Num_OpClasses, 0, 99, 2) 238 .name(name() + ".IQ:residence:") 239 .desc("cycles from dispatch to issue") 240 .flags(total | pdf | cdf ) 241 ; 242 for (int i = 0; i < Num_OpClasses; ++i) { 243 queueResDist.subname(i, opClassStrings[i]); 244 } 245*/ 246 numIssuedDist 247 .init(0,totalWidth,1) 248 .name(name() + ".ISSUE:issued_per_cycle") 249 .desc("Number of insts issued each cycle") 250 .flags(pdf) 251 ; 252/* 253 dist_unissued 254 .init(Num_OpClasses+2) 255 .name(name() + ".ISSUE:unissued_cause") 256 .desc("Reason ready instruction not issued") 257 .flags(pdf | dist) 258 ; 259 for (int i=0; i < (Num_OpClasses + 2); ++i) { 260 dist_unissued.subname(i, unissued_names[i]); 261 } 262*/ 263 statIssuedInstType 264 .init(numThreads,Num_OpClasses) 265 .name(name() + ".ISSUE:FU_type") 266 .desc("Type of FU issued") 267 .flags(total | pdf | dist) 268 ; 269 statIssuedInstType.ysubnames(opClassStrings); 270 271 // 272 // How long did instructions for a particular FU type wait prior to issue 273 // 274/* 275 issueDelayDist 276 .init(Num_OpClasses,0,99,2) 277 .name(name() + ".ISSUE:") 278 .desc("cycles from operands ready to issue") 279 .flags(pdf | cdf) 280 ; 281 282 for (int i=0; i<Num_OpClasses; ++i) { 283 std::stringstream subname; 284 subname << opClassStrings[i] << "_delay"; 285 issueDelayDist.subname(i, subname.str()); 286 } 287*/ 288 issueRate 289 .name(name() + ".ISSUE:rate") 290 .desc("Inst issue rate") 291 .flags(total) 292 ; 293 issueRate = iqInstsIssued / cpu->numCycles; 294 295 statFuBusy 296 .init(Num_OpClasses) 297 .name(name() + ".ISSUE:fu_full") 298 .desc("attempts to use FU when none available") 299 .flags(pdf | dist) 300 ; 301 for (int i=0; i < Num_OpClasses; ++i) { 302 statFuBusy.subname(i, opClassStrings[i]); 303 } 304 305 fuBusy 306 .init(numThreads) 307 .name(name() + ".ISSUE:fu_busy_cnt") 308 .desc("FU busy when requested") 309 .flags(total) 310 ; 311 312 fuBusyRate 313 .name(name() + ".ISSUE:fu_busy_rate") 314 .desc("FU busy rate (busy events/executed inst)") 315 .flags(total) 316 ; 317 fuBusyRate = fuBusy / iqInstsIssued; 318 319 for ( int i=0; i < numThreads; i++) { 320 // Tell mem dependence unit to reg stats as well. 321 memDepUnit[i].regStats(); 322 } 323} 324 325template <class Impl> 326void 327InstructionQueue<Impl>::resetState() 328{ 329 //Initialize thread IQ counts 330 for (int i = 0; i <numThreads; i++) { 331 count[i] = 0; 332 instList[i].clear(); 333 } 334 335 // Initialize the number of free IQ entries. 336 freeEntries = numEntries; 337 338 // Note that in actuality, the registers corresponding to the logical 339 // registers start off as ready. However this doesn't matter for the 340 // IQ as the instruction should have been correctly told if those 341 // registers are ready in rename. Thus it can all be initialized as 342 // unready. 343 for (int i = 0; i < numPhysRegs; ++i) { 344 regScoreboard[i] = false; 345 } 346 347 for (int i = 0; i < numThreads; ++i) { 348 squashedSeqNum[i] = 0; 349 } 350 351 for (int i = 0; i < Num_OpClasses; ++i) { 352 while (!readyInsts[i].empty()) 353 readyInsts[i].pop(); 354 queueOnList[i] = false; 355 readyIt[i] = listOrder.end(); 356 } 357 nonSpecInsts.clear(); 358 listOrder.clear(); 359} 360 361template <class Impl> 362void 363InstructionQueue<Impl>::setActiveThreads(std::list<unsigned> *at_ptr) 364{ 365 activeThreads = at_ptr; 366} 367 368template <class Impl> 369void 370InstructionQueue<Impl>::setIssueToExecuteQueue(TimeBuffer<IssueStruct> *i2e_ptr) 371{ 372 issueToExecuteQueue = i2e_ptr; 373} 374 375template <class Impl> 376void 377InstructionQueue<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) 378{ 379 timeBuffer = tb_ptr; 380 381 fromCommit = timeBuffer->getWire(-commitToIEWDelay); 382} 383 384template <class Impl> 385void 386InstructionQueue<Impl>::switchOut() 387{ 388/* 389 if (!instList[0].empty() || (numEntries != freeEntries) || 390 !readyInsts[0].empty() || !nonSpecInsts.empty() || !listOrder.empty()) { 391 dumpInsts(); 392// assert(0); 393 } 394*/ 395 resetState(); 396 dependGraph.reset(); 397 instsToExecute.clear(); 398 switchedOut = true; 399 for (int i = 0; i < numThreads; ++i) { 400 memDepUnit[i].switchOut(); 401 } 402} 403 404template <class Impl> 405void 406InstructionQueue<Impl>::takeOverFrom() 407{ 408 switchedOut = false; 409} 410 411template <class Impl> 412int 413InstructionQueue<Impl>::entryAmount(int num_threads) 414{ 415 if (iqPolicy == Partitioned) { 416 return numEntries / num_threads; 417 } else { 418 return 0; 419 } 420} 421 422 423template <class Impl> 424void 425InstructionQueue<Impl>::resetEntries() 426{ 427 if (iqPolicy != Dynamic || numThreads > 1) { 428 int active_threads = activeThreads->size(); 429 430 std::list<unsigned>::iterator threads = activeThreads->begin(); 431 std::list<unsigned>::iterator end = activeThreads->end(); 432 433 while (threads != end) { 434 unsigned tid = *threads++; 435 436 if (iqPolicy == Partitioned) { 437 maxEntries[tid] = numEntries / active_threads; 438 } else if(iqPolicy == Threshold && active_threads == 1) { 439 maxEntries[tid] = numEntries; 440 } 441 } 442 } 443} 444 445template <class Impl> 446unsigned 447InstructionQueue<Impl>::numFreeEntries() 448{ 449 return freeEntries; 450} 451 452template <class Impl> 453unsigned 454InstructionQueue<Impl>::numFreeEntries(unsigned tid) 455{ 456 return maxEntries[tid] - count[tid]; 457} 458 459// Might want to do something more complex if it knows how many instructions 460// will be issued this cycle. 461template <class Impl> 462bool 463InstructionQueue<Impl>::isFull() 464{ 465 if (freeEntries == 0) { 466 return(true); 467 } else { 468 return(false); 469 } 470} 471 472template <class Impl> 473bool 474InstructionQueue<Impl>::isFull(unsigned tid) 475{ 476 if (numFreeEntries(tid) == 0) { 477 return(true); 478 } else { 479 return(false); 480 } 481} 482 483template <class Impl> 484bool 485InstructionQueue<Impl>::hasReadyInsts() 486{ 487 if (!listOrder.empty()) { 488 return true; 489 } 490 491 for (int i = 0; i < Num_OpClasses; ++i) { 492 if (!readyInsts[i].empty()) { 493 return true; 494 } 495 } 496 497 return false; 498} 499 500template <class Impl> 501void 502InstructionQueue<Impl>::insert(DynInstPtr &new_inst) 503{ 504 // Make sure the instruction is valid 505 assert(new_inst); 506 507 DPRINTF(IQ, "Adding instruction [sn:%lli] PC %#x to the IQ.\n", 508 new_inst->seqNum, new_inst->readPC()); 509 510 assert(freeEntries != 0); 511 512 instList[new_inst->threadNumber].push_back(new_inst); 513 514 --freeEntries; 515 516 new_inst->setInIQ(); 517 518 // Look through its source registers (physical regs), and mark any 519 // dependencies. 520 addToDependents(new_inst); 521 522 // Have this instruction set itself as the producer of its destination 523 // register(s). 524 addToProducers(new_inst); 525 526 if (new_inst->isMemRef()) { 527 memDepUnit[new_inst->threadNumber].insert(new_inst); 528 } else { 529 addIfReady(new_inst); 530 } 531 532 ++iqInstsAdded; 533 534 count[new_inst->threadNumber]++; 535 536 assert(freeEntries == (numEntries - countInsts())); 537} 538 539template <class Impl> 540void 541InstructionQueue<Impl>::insertNonSpec(DynInstPtr &new_inst) 542{ 543 // @todo: Clean up this code; can do it by setting inst as unable 544 // to issue, then calling normal insert on the inst. 545 546 assert(new_inst); 547 548 nonSpecInsts[new_inst->seqNum] = new_inst; 549 550 DPRINTF(IQ, "Adding non-speculative instruction [sn:%lli] PC %#x " 551 "to the IQ.\n", 552 new_inst->seqNum, new_inst->readPC()); 553 554 assert(freeEntries != 0); 555 556 instList[new_inst->threadNumber].push_back(new_inst); 557 558 --freeEntries; 559 560 new_inst->setInIQ(); 561 562 // Have this instruction set itself as the producer of its destination 563 // register(s). 564 addToProducers(new_inst); 565 566 // If it's a memory instruction, add it to the memory dependency 567 // unit. 568 if (new_inst->isMemRef()) { 569 memDepUnit[new_inst->threadNumber].insertNonSpec(new_inst); 570 } 571 572 ++iqNonSpecInstsAdded; 573 574 count[new_inst->threadNumber]++; 575 576 assert(freeEntries == (numEntries - countInsts())); 577} 578 579template <class Impl> 580void 581InstructionQueue<Impl>::insertBarrier(DynInstPtr &barr_inst) 582{ 583 memDepUnit[barr_inst->threadNumber].insertBarrier(barr_inst); 584 585 insertNonSpec(barr_inst); 586} 587 588template <class Impl> 589typename Impl::DynInstPtr 590InstructionQueue<Impl>::getInstToExecute() 591{ 592 assert(!instsToExecute.empty()); 593 DynInstPtr inst = instsToExecute.front(); 594 instsToExecute.pop_front(); 595 return inst; 596} 597 598template <class Impl> 599void 600InstructionQueue<Impl>::addToOrderList(OpClass op_class) 601{ 602 assert(!readyInsts[op_class].empty()); 603 604 ListOrderEntry queue_entry; 605 606 queue_entry.queueType = op_class; 607 608 queue_entry.oldestInst = readyInsts[op_class].top()->seqNum; 609 610 ListOrderIt list_it = listOrder.begin(); 611 ListOrderIt list_end_it = listOrder.end(); 612 613 while (list_it != list_end_it) { 614 if ((*list_it).oldestInst > queue_entry.oldestInst) { 615 break; 616 } 617 618 list_it++; 619 } 620 621 readyIt[op_class] = listOrder.insert(list_it, queue_entry); 622 queueOnList[op_class] = true; 623} 624 625template <class Impl> 626void 627InstructionQueue<Impl>::moveToYoungerInst(ListOrderIt list_order_it) 628{ 629 // Get iterator of next item on the list 630 // Delete the original iterator 631 // Determine if the next item is either the end of the list or younger 632 // than the new instruction. If so, then add in a new iterator right here. 633 // If not, then move along. 634 ListOrderEntry queue_entry; 635 OpClass op_class = (*list_order_it).queueType; 636 ListOrderIt next_it = list_order_it; 637 638 ++next_it; 639 640 queue_entry.queueType = op_class; 641 queue_entry.oldestInst = readyInsts[op_class].top()->seqNum; 642 643 while (next_it != listOrder.end() && 644 (*next_it).oldestInst < queue_entry.oldestInst) { 645 ++next_it; 646 } 647 648 readyIt[op_class] = listOrder.insert(next_it, queue_entry); 649} 650 651template <class Impl> 652void 653InstructionQueue<Impl>::processFUCompletion(DynInstPtr &inst, int fu_idx) 654{ 655 DPRINTF(IQ, "Processing FU completion [sn:%lli]\n", inst->seqNum); 656 // The CPU could have been sleeping until this op completed (*extremely* 657 // long latency op). Wake it if it was. This may be overkill. 658 if (isSwitchedOut()) { 659 DPRINTF(IQ, "FU completion not processed, IQ is switched out [sn:%lli]\n", 660 inst->seqNum); 661 return; 662 } 663 664 iewStage->wakeCPU(); 665 666 if (fu_idx > -1) 667 fuPool->freeUnitNextCycle(fu_idx); 668 669 // @todo: Ensure that these FU Completions happen at the beginning 670 // of a cycle, otherwise they could add too many instructions to 671 // the queue. 672 issueToExecuteQueue->access(0)->size++; 673 instsToExecute.push_back(inst); 674} 675 676// @todo: Figure out a better way to remove the squashed items from the 677// lists. Checking the top item of each list to see if it's squashed 678// wastes time and forces jumps. 679template <class Impl> 680void 681InstructionQueue<Impl>::scheduleReadyInsts() 682{ 683 DPRINTF(IQ, "Attempting to schedule ready instructions from " 684 "the IQ.\n"); 685 686 IssueStruct *i2e_info = issueToExecuteQueue->access(0); 687 688 // Have iterator to head of the list 689 // While I haven't exceeded bandwidth or reached the end of the list, 690 // Try to get a FU that can do what this op needs. 691 // If successful, change the oldestInst to the new top of the list, put 692 // the queue in the proper place in the list. 693 // Increment the iterator. 694 // This will avoid trying to schedule a certain op class if there are no 695 // FUs that handle it. 696 ListOrderIt order_it = listOrder.begin(); 697 ListOrderIt order_end_it = listOrder.end(); 698 int total_issued = 0; 699 700 while (total_issued < totalWidth && 701 iewStage->canIssue() && 702 order_it != order_end_it) { 703 OpClass op_class = (*order_it).queueType; 704 705 assert(!readyInsts[op_class].empty()); 706 707 DynInstPtr issuing_inst = readyInsts[op_class].top(); 708 709 assert(issuing_inst->seqNum == (*order_it).oldestInst); 710 711 if (issuing_inst->isSquashed()) { 712 readyInsts[op_class].pop(); 713 714 if (!readyInsts[op_class].empty()) { 715 moveToYoungerInst(order_it); 716 } else { 717 readyIt[op_class] = listOrder.end(); 718 queueOnList[op_class] = false; 719 } 720 721 listOrder.erase(order_it++); 722 723 ++iqSquashedInstsIssued; 724 725 continue; 726 } 727 728 int idx = -2; 729 int op_latency = 1; 730 int tid = issuing_inst->threadNumber; 731 732 if (op_class != No_OpClass) { 733 idx = fuPool->getUnit(op_class); 734 735 if (idx > -1) { 736 op_latency = fuPool->getOpLatency(op_class); 737 } 738 } 739 740 // If we have an instruction that doesn't require a FU, or a 741 // valid FU, then schedule for execution. 742 if (idx == -2 || idx != -1) { 743 if (op_latency == 1) { 744 i2e_info->size++; 745 instsToExecute.push_back(issuing_inst); 746 747 // Add the FU onto the list of FU's to be freed next 748 // cycle if we used one. 749 if (idx >= 0) 750 fuPool->freeUnitNextCycle(idx); 751 } else { 752 int issue_latency = fuPool->getIssueLatency(op_class); 753 // Generate completion event for the FU 754 FUCompletion *execution = new FUCompletion(issuing_inst, 755 idx, this); 756 757 execution->schedule(curTick + cpu->cycles(issue_latency - 1)); 758 759 // @todo: Enforce that issue_latency == 1 or op_latency 760 if (issue_latency > 1) { 761 // If FU isn't pipelined, then it must be freed 762 // upon the execution completing. 763 execution->setFreeFU(); 764 } else { 765 // Add the FU onto the list of FU's to be freed next cycle. 766 fuPool->freeUnitNextCycle(idx); 767 } 768 } 769 770 DPRINTF(IQ, "Thread %i: Issuing instruction PC %#x " 771 "[sn:%lli]\n", 772 tid, issuing_inst->readPC(), 773 issuing_inst->seqNum); 774 775 readyInsts[op_class].pop(); 776 777 if (!readyInsts[op_class].empty()) { 778 moveToYoungerInst(order_it); 779 } else { 780 readyIt[op_class] = listOrder.end(); 781 queueOnList[op_class] = false; 782 } 783 784 issuing_inst->setIssued(); 785 ++total_issued; 786 787 if (!issuing_inst->isMemRef()) { 788 // Memory instructions can not be freed from the IQ until they 789 // complete. 790 ++freeEntries; 791 count[tid]--; 792 issuing_inst->clearInIQ(); 793 } else { 794 memDepUnit[tid].issue(issuing_inst); 795 } 796 797 listOrder.erase(order_it++); 798 statIssuedInstType[tid][op_class]++; 799 iewStage->incrWb(issuing_inst->seqNum); 800 } else { 801 statFuBusy[op_class]++; 802 fuBusy[tid]++; 803 ++order_it; 804 } 805 } 806 807 numIssuedDist.sample(total_issued); 808 iqInstsIssued+= total_issued; 809 810 // If we issued any instructions, tell the CPU we had activity. 811 if (total_issued) { 812 cpu->activityThisCycle(); 813 } else { 814 DPRINTF(IQ, "Not able to schedule any instructions.\n"); 815 } 816} 817 818template <class Impl> 819void 820InstructionQueue<Impl>::scheduleNonSpec(const InstSeqNum &inst) 821{ 822 DPRINTF(IQ, "Marking nonspeculative instruction [sn:%lli] as ready " 823 "to execute.\n", inst); 824 825 NonSpecMapIt inst_it = nonSpecInsts.find(inst); 826 827 assert(inst_it != nonSpecInsts.end()); 828 829 unsigned tid = (*inst_it).second->threadNumber; 830 831 (*inst_it).second->setAtCommit(); 832 833 (*inst_it).second->setCanIssue(); 834 835 if (!(*inst_it).second->isMemRef()) { 836 addIfReady((*inst_it).second); 837 } else { 838 memDepUnit[tid].nonSpecInstReady((*inst_it).second); 839 } 840 841 (*inst_it).second = NULL; 842 843 nonSpecInsts.erase(inst_it); 844} 845 846template <class Impl> 847void 848InstructionQueue<Impl>::commit(const InstSeqNum &inst, unsigned tid) 849{ 850 DPRINTF(IQ, "[tid:%i]: Committing instructions older than [sn:%i]\n", 851 tid,inst); 852 853 ListIt iq_it = instList[tid].begin(); 854 855 while (iq_it != instList[tid].end() && 856 (*iq_it)->seqNum <= inst) { 857 ++iq_it; 858 instList[tid].pop_front(); 859 } 860 861 assert(freeEntries == (numEntries - countInsts())); 862} 863 864template <class Impl> 865int 866InstructionQueue<Impl>::wakeDependents(DynInstPtr &completed_inst) 867{ 868 int dependents = 0; 869 870 DPRINTF(IQ, "Waking dependents of completed instruction.\n"); 871 872 assert(!completed_inst->isSquashed()); 873 874 // Tell the memory dependence unit to wake any dependents on this 875 // instruction if it is a memory instruction. Also complete the memory 876 // instruction at this point since we know it executed without issues. 877 // @todo: Might want to rename "completeMemInst" to something that 878 // indicates that it won't need to be replayed, and call this 879 // earlier. Might not be a big deal. 880 if (completed_inst->isMemRef()) { 881 memDepUnit[completed_inst->threadNumber].wakeDependents(completed_inst); 882 completeMemInst(completed_inst); 883 } else if (completed_inst->isMemBarrier() || 884 completed_inst->isWriteBarrier()) { 885 memDepUnit[completed_inst->threadNumber].completeBarrier(completed_inst); 886 } 887 888 for (int dest_reg_idx = 0; 889 dest_reg_idx < completed_inst->numDestRegs(); 890 dest_reg_idx++) 891 { 892 PhysRegIndex dest_reg = 893 completed_inst->renamedDestRegIdx(dest_reg_idx); 894 895 // Special case of uniq or control registers. They are not 896 // handled by the IQ and thus have no dependency graph entry. 897 // @todo Figure out a cleaner way to handle this. 898 if (dest_reg >= numPhysRegs) { 899 continue; 900 } 901 902 DPRINTF(IQ, "Waking any dependents on register %i.\n", 903 (int) dest_reg); 904 905 //Go through the dependency chain, marking the registers as 906 //ready within the waiting instructions. 907 DynInstPtr dep_inst = dependGraph.pop(dest_reg); 908 909 while (dep_inst) { 910 DPRINTF(IQ, "Waking up a dependent instruction, PC%#x.\n", 911 dep_inst->readPC()); 912 913 // Might want to give more information to the instruction 914 // so that it knows which of its source registers is 915 // ready. However that would mean that the dependency 916 // graph entries would need to hold the src_reg_idx. 917 dep_inst->markSrcRegReady(); 918 919 addIfReady(dep_inst); 920 921 dep_inst = dependGraph.pop(dest_reg); 922 923 ++dependents; 924 } 925 926 // Reset the head node now that all of its dependents have 927 // been woken up. 928 assert(dependGraph.empty(dest_reg)); 929 dependGraph.clearInst(dest_reg); 930 931 // Mark the scoreboard as having that register ready. 932 regScoreboard[dest_reg] = true; 933 } 934 return dependents; 935} 936 937template <class Impl> 938void 939InstructionQueue<Impl>::addReadyMemInst(DynInstPtr &ready_inst) 940{ 941 OpClass op_class = ready_inst->opClass(); 942 943 readyInsts[op_class].push(ready_inst); 944 945 // Will need to reorder the list if either a queue is not on the list, 946 // or it has an older instruction than last time. 947 if (!queueOnList[op_class]) { 948 addToOrderList(op_class); 949 } else if (readyInsts[op_class].top()->seqNum < 950 (*readyIt[op_class]).oldestInst) { 951 listOrder.erase(readyIt[op_class]); 952 addToOrderList(op_class); 953 } 954 955 DPRINTF(IQ, "Instruction is ready to issue, putting it onto " 956 "the ready list, PC %#x opclass:%i [sn:%lli].\n", 957 ready_inst->readPC(), op_class, ready_inst->seqNum); 958} 959 960template <class Impl> 961void 962InstructionQueue<Impl>::rescheduleMemInst(DynInstPtr &resched_inst) 963{ 964 DPRINTF(IQ, "Rescheduling mem inst [sn:%lli]\n", resched_inst->seqNum); 965 resched_inst->clearCanIssue(); 966 memDepUnit[resched_inst->threadNumber].reschedule(resched_inst); 967} 968 969template <class Impl> 970void 971InstructionQueue<Impl>::replayMemInst(DynInstPtr &replay_inst) 972{ 973 memDepUnit[replay_inst->threadNumber].replay(replay_inst); 974} 975 976template <class Impl> 977void 978InstructionQueue<Impl>::completeMemInst(DynInstPtr &completed_inst) 979{ 980 int tid = completed_inst->threadNumber; 981 982 DPRINTF(IQ, "Completing mem instruction PC:%#x [sn:%lli]\n", 983 completed_inst->readPC(), completed_inst->seqNum); 984 985 ++freeEntries; 986 987 completed_inst->memOpDone = true; 988 989 memDepUnit[tid].completed(completed_inst); 990 count[tid]--; 991} 992 993template <class Impl> 994void 995InstructionQueue<Impl>::violation(DynInstPtr &store, 996 DynInstPtr &faulting_load) 997{ 998 memDepUnit[store->threadNumber].violation(store, faulting_load); 999} 1000 1001template <class Impl> 1002void 1003InstructionQueue<Impl>::squash(unsigned tid) 1004{ 1005 DPRINTF(IQ, "[tid:%i]: Starting to squash instructions in " 1006 "the IQ.\n", tid); 1007 1008 // Read instruction sequence number of last instruction out of the 1009 // time buffer. 1010#if ISA_HAS_DELAY_SLOT 1011 squashedSeqNum[tid] = fromCommit->commitInfo[tid].bdelayDoneSeqNum; 1012#else 1013 squashedSeqNum[tid] = fromCommit->commitInfo[tid].doneSeqNum; 1014#endif 1015 1016 // Call doSquash if there are insts in the IQ 1017 if (count[tid] > 0) { 1018 doSquash(tid); 1019 } 1020 1021 // Also tell the memory dependence unit to squash. 1022 memDepUnit[tid].squash(squashedSeqNum[tid], tid); 1023} 1024 1025template <class Impl> 1026void 1027InstructionQueue<Impl>::doSquash(unsigned tid) 1028{ 1029 // Start at the tail. 1030 ListIt squash_it = instList[tid].end(); 1031 --squash_it; 1032 1033 DPRINTF(IQ, "[tid:%i]: Squashing until sequence number %i!\n", 1034 tid, squashedSeqNum[tid]); 1035 1036 // Squash any instructions younger than the squashed sequence number 1037 // given. 1038 while (squash_it != instList[tid].end() && 1039 (*squash_it)->seqNum > squashedSeqNum[tid]) { 1040 1041 DynInstPtr squashed_inst = (*squash_it); 1042 1043 // Only handle the instruction if it actually is in the IQ and 1044 // hasn't already been squashed in the IQ. 1045 if (squashed_inst->threadNumber != tid || 1046 squashed_inst->isSquashedInIQ()) { 1047 --squash_it; 1048 continue; 1049 } 1050 1051 if (!squashed_inst->isIssued() || 1052 (squashed_inst->isMemRef() && 1053 !squashed_inst->memOpDone)) { 1054 1055 DPRINTF(IQ, "[tid:%i]: Instruction [sn:%lli] PC %#x " 1056 "squashed.\n", 1057 tid, squashed_inst->seqNum, squashed_inst->readPC()); 1058 1059 // Remove the instruction from the dependency list. 1060 if (!squashed_inst->isNonSpeculative() && 1061 !squashed_inst->isStoreConditional() && 1062 !squashed_inst->isMemBarrier() && 1063 !squashed_inst->isWriteBarrier()) { 1064 1065 for (int src_reg_idx = 0; 1066 src_reg_idx < squashed_inst->numSrcRegs(); 1067 src_reg_idx++) 1068 { 1069 PhysRegIndex src_reg = 1070 squashed_inst->renamedSrcRegIdx(src_reg_idx); 1071 1072 // Only remove it from the dependency graph if it 1073 // was placed there in the first place. 1074 1075 // Instead of doing a linked list traversal, we 1076 // can just remove these squashed instructions 1077 // either at issue time, or when the register is 1078 // overwritten. The only downside to this is it 1079 // leaves more room for error. 1080 1081 if (!squashed_inst->isReadySrcRegIdx(src_reg_idx) && 1082 src_reg < numPhysRegs) { 1083 dependGraph.remove(src_reg, squashed_inst); 1084 } 1085 1086 1087 ++iqSquashedOperandsExamined; 1088 } 1089 } else if (!squashed_inst->isStoreConditional() || 1090 !squashed_inst->isCompleted()) { 1091 NonSpecMapIt ns_inst_it = 1092 nonSpecInsts.find(squashed_inst->seqNum); 1093 assert(ns_inst_it != nonSpecInsts.end()); 1094 if (ns_inst_it == nonSpecInsts.end()) { 1095 assert(squashed_inst->getFault() != NoFault); 1096 } else { 1097 1098 (*ns_inst_it).second = NULL; 1099 1100 nonSpecInsts.erase(ns_inst_it); 1101 1102 ++iqSquashedNonSpecRemoved; 1103 } 1104 } 1105 1106 // Might want to also clear out the head of the dependency graph. 1107 1108 // Mark it as squashed within the IQ. 1109 squashed_inst->setSquashedInIQ(); 1110 1111 // @todo: Remove this hack where several statuses are set so the 1112 // inst will flow through the rest of the pipeline. 1113 squashed_inst->setIssued(); 1114 squashed_inst->setCanCommit(); 1115 squashed_inst->clearInIQ(); 1116 1117 //Update Thread IQ Count 1118 count[squashed_inst->threadNumber]--; 1119 1120 ++freeEntries; 1121 } 1122 1123 instList[tid].erase(squash_it--); 1124 ++iqSquashedInstsExamined; 1125 } 1126} 1127 1128template <class Impl> 1129bool 1130InstructionQueue<Impl>::addToDependents(DynInstPtr &new_inst) 1131{ 1132 // Loop through the instruction's source registers, adding 1133 // them to the dependency list if they are not ready. 1134 int8_t total_src_regs = new_inst->numSrcRegs(); 1135 bool return_val = false; 1136 1137 for (int src_reg_idx = 0; 1138 src_reg_idx < total_src_regs; 1139 src_reg_idx++) 1140 { 1141 // Only add it to the dependency graph if it's not ready. 1142 if (!new_inst->isReadySrcRegIdx(src_reg_idx)) { 1143 PhysRegIndex src_reg = new_inst->renamedSrcRegIdx(src_reg_idx); 1144 1145 // Check the IQ's scoreboard to make sure the register 1146 // hasn't become ready while the instruction was in flight 1147 // between stages. Only if it really isn't ready should 1148 // it be added to the dependency graph. 1149 if (src_reg >= numPhysRegs) { 1150 continue; 1151 } else if (regScoreboard[src_reg] == false) { 1152 DPRINTF(IQ, "Instruction PC %#x has src reg %i that " 1153 "is being added to the dependency chain.\n", 1154 new_inst->readPC(), src_reg); 1155 1156 dependGraph.insert(src_reg, new_inst); 1157 1158 // Change the return value to indicate that something 1159 // was added to the dependency graph. 1160 return_val = true; 1161 } else { 1162 DPRINTF(IQ, "Instruction PC %#x has src reg %i that " 1163 "became ready before it reached the IQ.\n", 1164 new_inst->readPC(), src_reg); 1165 // Mark a register ready within the instruction. 1166 new_inst->markSrcRegReady(src_reg_idx); 1167 } 1168 } 1169 } 1170 1171 return return_val; 1172} 1173 1174template <class Impl> 1175void 1176InstructionQueue<Impl>::addToProducers(DynInstPtr &new_inst) 1177{ 1178 // Nothing really needs to be marked when an instruction becomes 1179 // the producer of a register's value, but for convenience a ptr 1180 // to the producing instruction will be placed in the head node of 1181 // the dependency links. 1182 int8_t total_dest_regs = new_inst->numDestRegs(); 1183 1184 for (int dest_reg_idx = 0; 1185 dest_reg_idx < total_dest_regs; 1186 dest_reg_idx++) 1187 { 1188 PhysRegIndex dest_reg = new_inst->renamedDestRegIdx(dest_reg_idx); 1189 1190 // Instructions that use the misc regs will have a reg number 1191 // higher than the normal physical registers. In this case these 1192 // registers are not renamed, and there is no need to track 1193 // dependencies as these instructions must be executed at commit. 1194 if (dest_reg >= numPhysRegs) { 1195 continue; 1196 } 1197 1198 if (!dependGraph.empty(dest_reg)) { 1199 dependGraph.dump(); 1200 panic("Dependency graph %i not empty!", dest_reg); 1201 } 1202 1203 dependGraph.setInst(dest_reg, new_inst); 1204 1205 // Mark the scoreboard to say it's not yet ready. 1206 regScoreboard[dest_reg] = false; 1207 } 1208} 1209 1210template <class Impl> 1211void 1212InstructionQueue<Impl>::addIfReady(DynInstPtr &inst) 1213{ 1214 // If the instruction now has all of its source registers 1215 // available, then add it to the list of ready instructions. 1216 if (inst->readyToIssue()) { 1217 1218 //Add the instruction to the proper ready list. 1219 if (inst->isMemRef()) { 1220 1221 DPRINTF(IQ, "Checking if memory instruction can issue.\n"); 1222 1223 // Message to the mem dependence unit that this instruction has 1224 // its registers ready. 1225 memDepUnit[inst->threadNumber].regsReady(inst); 1226 1227 return; 1228 } 1229 1230 OpClass op_class = inst->opClass(); 1231 1232 DPRINTF(IQ, "Instruction is ready to issue, putting it onto " 1233 "the ready list, PC %#x opclass:%i [sn:%lli].\n", 1234 inst->readPC(), op_class, inst->seqNum); 1235 1236 readyInsts[op_class].push(inst); 1237 1238 // Will need to reorder the list if either a queue is not on the list, 1239 // or it has an older instruction than last time. 1240 if (!queueOnList[op_class]) { 1241 addToOrderList(op_class); 1242 } else if (readyInsts[op_class].top()->seqNum < 1243 (*readyIt[op_class]).oldestInst) { 1244 listOrder.erase(readyIt[op_class]); 1245 addToOrderList(op_class); 1246 } 1247 } 1248} 1249 1250template <class Impl> 1251int 1252InstructionQueue<Impl>::countInsts() 1253{ 1254#if 0 1255 //ksewell:This works but definitely could use a cleaner write 1256 //with a more intuitive way of counting. Right now it's 1257 //just brute force .... 1258 // Change the #if if you want to use this method. 1259 int total_insts = 0; 1260 1261 for (int i = 0; i < numThreads; ++i) { 1262 ListIt count_it = instList[i].begin(); 1263 1264 while (count_it != instList[i].end()) { 1265 if (!(*count_it)->isSquashed() && !(*count_it)->isSquashedInIQ()) { 1266 if (!(*count_it)->isIssued()) { 1267 ++total_insts; 1268 } else if ((*count_it)->isMemRef() && 1269 !(*count_it)->memOpDone) { 1270 // Loads that have not been marked as executed still count 1271 // towards the total instructions. 1272 ++total_insts; 1273 } 1274 } 1275 1276 ++count_it; 1277 } 1278 } 1279 1280 return total_insts; 1281#else 1282 return numEntries - freeEntries; 1283#endif 1284} 1285 1286template <class Impl> 1287void 1288InstructionQueue<Impl>::dumpLists() 1289{ 1290 for (int i = 0; i < Num_OpClasses; ++i) { 1291 cprintf("Ready list %i size: %i\n", i, readyInsts[i].size()); 1292 1293 cprintf("\n"); 1294 } 1295 1296 cprintf("Non speculative list size: %i\n", nonSpecInsts.size()); 1297 1298 NonSpecMapIt non_spec_it = nonSpecInsts.begin(); 1299 NonSpecMapIt non_spec_end_it = nonSpecInsts.end(); 1300 1301 cprintf("Non speculative list: "); 1302 1303 while (non_spec_it != non_spec_end_it) { 1304 cprintf("%#x [sn:%lli]", (*non_spec_it).second->readPC(), 1305 (*non_spec_it).second->seqNum); 1306 ++non_spec_it; 1307 } 1308 1309 cprintf("\n"); 1310 1311 ListOrderIt list_order_it = listOrder.begin(); 1312 ListOrderIt list_order_end_it = listOrder.end(); 1313 int i = 1; 1314 1315 cprintf("List order: "); 1316 1317 while (list_order_it != list_order_end_it) { 1318 cprintf("%i OpClass:%i [sn:%lli] ", i, (*list_order_it).queueType, 1319 (*list_order_it).oldestInst); 1320 1321 ++list_order_it; 1322 ++i; 1323 } 1324 1325 cprintf("\n"); 1326} 1327 1328 1329template <class Impl> 1330void 1331InstructionQueue<Impl>::dumpInsts() 1332{ 1333 for (int i = 0; i < numThreads; ++i) { 1334 int num = 0; 1335 int valid_num = 0; 1336 ListIt inst_list_it = instList[i].begin(); 1337 1338 while (inst_list_it != instList[i].end()) 1339 { 1340 cprintf("Instruction:%i\n", 1341 num); 1342 if (!(*inst_list_it)->isSquashed()) { 1343 if (!(*inst_list_it)->isIssued()) { 1344 ++valid_num; 1345 cprintf("Count:%i\n", valid_num); 1346 } else if ((*inst_list_it)->isMemRef() && 1347 !(*inst_list_it)->memOpDone) { 1348 // Loads that have not been marked as executed 1349 // still count towards the total instructions. 1350 ++valid_num; 1351 cprintf("Count:%i\n", valid_num); 1352 } 1353 } 1354 1355 cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n" 1356 "Issued:%i\nSquashed:%i\n", 1357 (*inst_list_it)->readPC(), 1358 (*inst_list_it)->seqNum, 1359 (*inst_list_it)->threadNumber, 1360 (*inst_list_it)->isIssued(), 1361 (*inst_list_it)->isSquashed()); 1362 1363 if ((*inst_list_it)->isMemRef()) { 1364 cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone); 1365 } 1366 1367 cprintf("\n"); 1368 1369 inst_list_it++; 1370 ++num; 1371 } 1372 } 1373 1374 cprintf("Insts to Execute list:\n"); 1375 1376 int num = 0; 1377 int valid_num = 0; 1378 ListIt inst_list_it = instsToExecute.begin(); 1379 1380 while (inst_list_it != instsToExecute.end()) 1381 { 1382 cprintf("Instruction:%i\n", 1383 num); 1384 if (!(*inst_list_it)->isSquashed()) { 1385 if (!(*inst_list_it)->isIssued()) { 1386 ++valid_num; 1387 cprintf("Count:%i\n", valid_num); 1388 } else if ((*inst_list_it)->isMemRef() && 1389 !(*inst_list_it)->memOpDone) { 1390 // Loads that have not been marked as executed 1391 // still count towards the total instructions. 1392 ++valid_num; 1393 cprintf("Count:%i\n", valid_num); 1394 } 1395 } 1396 1397 cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n" 1398 "Issued:%i\nSquashed:%i\n", 1399 (*inst_list_it)->readPC(), 1400 (*inst_list_it)->seqNum, 1401 (*inst_list_it)->threadNumber, 1402 (*inst_list_it)->isIssued(), 1403 (*inst_list_it)->isSquashed()); 1404 1405 if ((*inst_list_it)->isMemRef()) { 1406 cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone); 1407 } 1408 1409 cprintf("\n"); 1410 1411 inst_list_it++; 1412 ++num; 1413 } 1414} 1415