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