mem_dep_unit_impl.hh revision 3500:8d5e32b3bc2e
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 */ 30 31#include <map> 32 33#include "cpu/o3/inst_queue.hh" 34#include "cpu/o3/mem_dep_unit.hh" 35 36template <class MemDepPred, class Impl> 37MemDepUnit<MemDepPred, Impl>::MemDepUnit() 38 : loadBarrier(false), loadBarrierSN(0), storeBarrier(false), 39 storeBarrierSN(0), iqPtr(NULL) 40{ 41} 42 43template <class MemDepPred, class Impl> 44MemDepUnit<MemDepPred, Impl>::MemDepUnit(Params *params) 45 : depPred(params->SSITSize, params->LFSTSize), loadBarrier(false), 46 loadBarrierSN(0), storeBarrier(false), storeBarrierSN(0), iqPtr(NULL) 47{ 48 DPRINTF(MemDepUnit, "Creating MemDepUnit object.\n"); 49} 50 51template <class MemDepPred, class Impl> 52MemDepUnit<MemDepPred, Impl>::~MemDepUnit() 53{ 54 for (int tid=0; tid < Impl::MaxThreads; tid++) { 55 56 ListIt inst_list_it = instList[tid].begin(); 57 58 MemDepHashIt hash_it; 59 60 while (!instList[tid].empty()) { 61 hash_it = memDepHash.find((*inst_list_it)->seqNum); 62 63 assert(hash_it != memDepHash.end()); 64 65 memDepHash.erase(hash_it); 66 67 instList[tid].erase(inst_list_it++); 68 } 69 } 70 71#ifdef DEBUG 72 assert(MemDepEntry::memdep_count == 0); 73#endif 74} 75 76template <class MemDepPred, class Impl> 77std::string 78MemDepUnit<MemDepPred, Impl>::name() const 79{ 80 return "memdepunit"; 81} 82 83template <class MemDepPred, class Impl> 84void 85MemDepUnit<MemDepPred, Impl>::init(Params *params, int tid) 86{ 87 DPRINTF(MemDepUnit, "Creating MemDepUnit %i object.\n",tid); 88 89 id = tid; 90 91 depPred.init(params->SSITSize, params->LFSTSize); 92} 93 94template <class MemDepPred, class Impl> 95void 96MemDepUnit<MemDepPred, Impl>::regStats() 97{ 98 insertedLoads 99 .name(name() + ".memDep.insertedLoads") 100 .desc("Number of loads inserted to the mem dependence unit."); 101 102 insertedStores 103 .name(name() + ".memDep.insertedStores") 104 .desc("Number of stores inserted to the mem dependence unit."); 105 106 conflictingLoads 107 .name(name() + ".memDep.conflictingLoads") 108 .desc("Number of conflicting loads."); 109 110 conflictingStores 111 .name(name() + ".memDep.conflictingStores") 112 .desc("Number of conflicting stores."); 113} 114 115template <class MemDepPred, class Impl> 116void 117MemDepUnit<MemDepPred, Impl>::switchOut() 118{ 119 assert(instList[0].empty()); 120 assert(instsToReplay.empty()); 121 assert(memDepHash.empty()); 122 // Clear any state. 123 for (int i = 0; i < Impl::MaxThreads; ++i) { 124 instList[i].clear(); 125 } 126 instsToReplay.clear(); 127 memDepHash.clear(); 128} 129 130template <class MemDepPred, class Impl> 131void 132MemDepUnit<MemDepPred, Impl>::takeOverFrom() 133{ 134 // Be sure to reset all state. 135 loadBarrier = storeBarrier = false; 136 loadBarrierSN = storeBarrierSN = 0; 137 depPred.clear(); 138} 139 140template <class MemDepPred, class Impl> 141void 142MemDepUnit<MemDepPred, Impl>::setIQ(InstructionQueue<Impl> *iq_ptr) 143{ 144 iqPtr = iq_ptr; 145} 146 147template <class MemDepPred, class Impl> 148void 149MemDepUnit<MemDepPred, Impl>::insert(DynInstPtr &inst) 150{ 151 unsigned tid = inst->threadNumber; 152 153 MemDepEntryPtr inst_entry = new MemDepEntry(inst); 154 155 // Add the MemDepEntry to the hash. 156 memDepHash.insert( 157 std::pair<InstSeqNum, MemDepEntryPtr>(inst->seqNum, inst_entry)); 158#ifdef DEBUG 159 MemDepEntry::memdep_insert++; 160#endif 161 162 instList[tid].push_back(inst); 163 164 inst_entry->listIt = --(instList[tid].end()); 165 166 // Check any barriers and the dependence predictor for any 167 // producing memrefs/stores. 168 InstSeqNum producing_store; 169 if (inst->isLoad() && loadBarrier) { 170 DPRINTF(MemDepUnit, "Load barrier [sn:%lli] in flight\n", 171 loadBarrierSN); 172 producing_store = loadBarrierSN; 173 } else if (inst->isStore() && storeBarrier) { 174 DPRINTF(MemDepUnit, "Store barrier [sn:%lli] in flight\n", 175 storeBarrierSN); 176 producing_store = storeBarrierSN; 177 } else { 178 producing_store = depPred.checkInst(inst->readPC()); 179 } 180 181 MemDepEntryPtr store_entry = NULL; 182 183 // If there is a producing store, try to find the entry. 184 if (producing_store != 0) { 185 DPRINTF(MemDepUnit, "Searching for producer\n"); 186 MemDepHashIt hash_it = memDepHash.find(producing_store); 187 188 if (hash_it != memDepHash.end()) { 189 store_entry = (*hash_it).second; 190 DPRINTF(MemDepUnit, "Proucer found\n"); 191 } 192 } 193 194 // If no store entry, then instruction can issue as soon as the registers 195 // are ready. 196 if (!store_entry) { 197 DPRINTF(MemDepUnit, "No dependency for inst PC " 198 "%#x [sn:%lli].\n", inst->readPC(), inst->seqNum); 199 200 inst_entry->memDepReady = true; 201 202 if (inst->readyToIssue()) { 203 inst_entry->regsReady = true; 204 205 moveToReady(inst_entry); 206 } 207 } else { 208 // Otherwise make the instruction dependent on the store/barrier. 209 DPRINTF(MemDepUnit, "Adding to dependency list; " 210 "inst PC %#x is dependent on [sn:%lli].\n", 211 inst->readPC(), producing_store); 212 213 if (inst->readyToIssue()) { 214 inst_entry->regsReady = true; 215 } 216 217 // Add this instruction to the list of dependents. 218 store_entry->dependInsts.push_back(inst_entry); 219 220 if (inst->isLoad()) { 221 ++conflictingLoads; 222 } else { 223 ++conflictingStores; 224 } 225 } 226 227 if (inst->isStore()) { 228 DPRINTF(MemDepUnit, "Inserting store PC %#x [sn:%lli].\n", 229 inst->readPC(), inst->seqNum); 230 231 depPred.insertStore(inst->readPC(), inst->seqNum, inst->threadNumber); 232 233 ++insertedStores; 234 } else if (inst->isLoad()) { 235 ++insertedLoads; 236 } else { 237 panic("Unknown type! (most likely a barrier)."); 238 } 239} 240 241template <class MemDepPred, class Impl> 242void 243MemDepUnit<MemDepPred, Impl>::insertNonSpec(DynInstPtr &inst) 244{ 245 unsigned tid = inst->threadNumber; 246 247 MemDepEntryPtr inst_entry = new MemDepEntry(inst); 248 249 // Insert the MemDepEntry into the hash. 250 memDepHash.insert( 251 std::pair<InstSeqNum, MemDepEntryPtr>(inst->seqNum, inst_entry)); 252#ifdef DEBUG 253 MemDepEntry::memdep_insert++; 254#endif 255 256 // Add the instruction to the list. 257 instList[tid].push_back(inst); 258 259 inst_entry->listIt = --(instList[tid].end()); 260 261 // Might want to turn this part into an inline function or something. 262 // It's shared between both insert functions. 263 if (inst->isStore()) { 264 DPRINTF(MemDepUnit, "Inserting store PC %#x [sn:%lli].\n", 265 inst->readPC(), inst->seqNum); 266 267 depPred.insertStore(inst->readPC(), inst->seqNum, inst->threadNumber); 268 269 ++insertedStores; 270 } else if (inst->isLoad()) { 271 ++insertedLoads; 272 } else { 273 panic("Unknown type! (most likely a barrier)."); 274 } 275} 276 277template <class MemDepPred, class Impl> 278void 279MemDepUnit<MemDepPred, Impl>::insertBarrier(DynInstPtr &barr_inst) 280{ 281 InstSeqNum barr_sn = barr_inst->seqNum; 282 // Memory barriers block loads and stores, write barriers only stores. 283 if (barr_inst->isMemBarrier()) { 284 loadBarrier = true; 285 loadBarrierSN = barr_sn; 286 storeBarrier = true; 287 storeBarrierSN = barr_sn; 288 DPRINTF(MemDepUnit, "Inserted a memory barrier\n"); 289 } else if (barr_inst->isWriteBarrier()) { 290 storeBarrier = true; 291 storeBarrierSN = barr_sn; 292 DPRINTF(MemDepUnit, "Inserted a write barrier\n"); 293 } 294 295 unsigned tid = barr_inst->threadNumber; 296 297 MemDepEntryPtr inst_entry = new MemDepEntry(barr_inst); 298 299 // Add the MemDepEntry to the hash. 300 memDepHash.insert( 301 std::pair<InstSeqNum, MemDepEntryPtr>(barr_sn, inst_entry)); 302#ifdef DEBUG 303 MemDepEntry::memdep_insert++; 304#endif 305 306 // Add the instruction to the instruction list. 307 instList[tid].push_back(barr_inst); 308 309 inst_entry->listIt = --(instList[tid].end()); 310} 311 312template <class MemDepPred, class Impl> 313void 314MemDepUnit<MemDepPred, Impl>::regsReady(DynInstPtr &inst) 315{ 316 DPRINTF(MemDepUnit, "Marking registers as ready for " 317 "instruction PC %#x [sn:%lli].\n", 318 inst->readPC(), inst->seqNum); 319 320 MemDepEntryPtr inst_entry = findInHash(inst); 321 322 inst_entry->regsReady = true; 323 324 if (inst_entry->memDepReady) { 325 DPRINTF(MemDepUnit, "Instruction has its memory " 326 "dependencies resolved, adding it to the ready list.\n"); 327 328 moveToReady(inst_entry); 329 } else { 330 DPRINTF(MemDepUnit, "Instruction still waiting on " 331 "memory dependency.\n"); 332 } 333} 334 335template <class MemDepPred, class Impl> 336void 337MemDepUnit<MemDepPred, Impl>::nonSpecInstReady(DynInstPtr &inst) 338{ 339 DPRINTF(MemDepUnit, "Marking non speculative " 340 "instruction PC %#x as ready [sn:%lli].\n", 341 inst->readPC(), inst->seqNum); 342 343 MemDepEntryPtr inst_entry = findInHash(inst); 344 345 moveToReady(inst_entry); 346} 347 348template <class MemDepPred, class Impl> 349void 350MemDepUnit<MemDepPred, Impl>::reschedule(DynInstPtr &inst) 351{ 352 instsToReplay.push_back(inst); 353} 354 355template <class MemDepPred, class Impl> 356void 357MemDepUnit<MemDepPred, Impl>::replay(DynInstPtr &inst) 358{ 359 DynInstPtr temp_inst; 360 bool found_inst = false; 361 362 // For now this replay function replays all waiting memory ops. 363 while (!instsToReplay.empty()) { 364 temp_inst = instsToReplay.front(); 365 366 MemDepEntryPtr inst_entry = findInHash(temp_inst); 367 368 DPRINTF(MemDepUnit, "Replaying mem instruction PC %#x " 369 "[sn:%lli].\n", 370 temp_inst->readPC(), temp_inst->seqNum); 371 372 moveToReady(inst_entry); 373 374 if (temp_inst == inst) { 375 found_inst = true; 376 } 377 378 instsToReplay.pop_front(); 379 } 380 381 assert(found_inst); 382} 383 384template <class MemDepPred, class Impl> 385void 386MemDepUnit<MemDepPred, Impl>::completed(DynInstPtr &inst) 387{ 388 DPRINTF(MemDepUnit, "Completed mem instruction PC %#x " 389 "[sn:%lli].\n", 390 inst->readPC(), inst->seqNum); 391 392 unsigned tid = inst->threadNumber; 393 394 // Remove the instruction from the hash and the list. 395 MemDepHashIt hash_it = memDepHash.find(inst->seqNum); 396 397 assert(hash_it != memDepHash.end()); 398 399 instList[tid].erase((*hash_it).second->listIt); 400 401 (*hash_it).second = NULL; 402 403 memDepHash.erase(hash_it); 404#ifdef DEBUG 405 MemDepEntry::memdep_erase++; 406#endif 407} 408 409template <class MemDepPred, class Impl> 410void 411MemDepUnit<MemDepPred, Impl>::completeBarrier(DynInstPtr &inst) 412{ 413 wakeDependents(inst); 414 completed(inst); 415 416 InstSeqNum barr_sn = inst->seqNum; 417 418 if (inst->isMemBarrier()) { 419 assert(loadBarrier && storeBarrier); 420 if (loadBarrierSN == barr_sn) 421 loadBarrier = false; 422 if (storeBarrierSN == barr_sn) 423 storeBarrier = false; 424 } else if (inst->isWriteBarrier()) { 425 assert(storeBarrier); 426 if (storeBarrierSN == barr_sn) 427 storeBarrier = false; 428 } 429} 430 431template <class MemDepPred, class Impl> 432void 433MemDepUnit<MemDepPred, Impl>::wakeDependents(DynInstPtr &inst) 434{ 435 // Only stores and barriers have dependents. 436 if (!inst->isStore() && !inst->isMemBarrier() && !inst->isWriteBarrier()) { 437 return; 438 } 439 440 MemDepEntryPtr inst_entry = findInHash(inst); 441 442 for (int i = 0; i < inst_entry->dependInsts.size(); ++i ) { 443 MemDepEntryPtr woken_inst = inst_entry->dependInsts[i]; 444 445 if (!woken_inst->inst) { 446 // Potentially removed mem dep entries could be on this list 447 continue; 448 } 449 450 DPRINTF(MemDepUnit, "Waking up a dependent inst, " 451 "[sn:%lli].\n", 452 woken_inst->inst->seqNum); 453 454 if (woken_inst->regsReady && !woken_inst->squashed) { 455 moveToReady(woken_inst); 456 } else { 457 woken_inst->memDepReady = true; 458 } 459 } 460 461 inst_entry->dependInsts.clear(); 462} 463 464template <class MemDepPred, class Impl> 465void 466MemDepUnit<MemDepPred, Impl>::squash(const InstSeqNum &squashed_num, 467 unsigned tid) 468{ 469 if (!instsToReplay.empty()) { 470 ListIt replay_it = instsToReplay.begin(); 471 while (replay_it != instsToReplay.end()) { 472 if ((*replay_it)->threadNumber == tid && 473 (*replay_it)->seqNum > squashed_num) { 474 instsToReplay.erase(replay_it++); 475 } else { 476 ++replay_it; 477 } 478 } 479 } 480 481 ListIt squash_it = instList[tid].end(); 482 --squash_it; 483 484 MemDepHashIt hash_it; 485 486 while (!instList[tid].empty() && 487 (*squash_it)->seqNum > squashed_num) { 488 489 DPRINTF(MemDepUnit, "Squashing inst [sn:%lli]\n", 490 (*squash_it)->seqNum); 491 492 hash_it = memDepHash.find((*squash_it)->seqNum); 493 494 assert(hash_it != memDepHash.end()); 495 496 (*hash_it).second->squashed = true; 497 498 (*hash_it).second = NULL; 499 500 memDepHash.erase(hash_it); 501#ifdef DEBUG 502 MemDepEntry::memdep_erase++; 503#endif 504 505 instList[tid].erase(squash_it--); 506 } 507 508 // Tell the dependency predictor to squash as well. 509 depPred.squash(squashed_num, tid); 510} 511 512template <class MemDepPred, class Impl> 513void 514MemDepUnit<MemDepPred, Impl>::violation(DynInstPtr &store_inst, 515 DynInstPtr &violating_load) 516{ 517 DPRINTF(MemDepUnit, "Passing violating PCs to store sets," 518 " load: %#x, store: %#x\n", violating_load->readPC(), 519 store_inst->readPC()); 520 // Tell the memory dependence unit of the violation. 521 depPred.violation(violating_load->readPC(), store_inst->readPC()); 522} 523 524template <class MemDepPred, class Impl> 525void 526MemDepUnit<MemDepPred, Impl>::issue(DynInstPtr &inst) 527{ 528 DPRINTF(MemDepUnit, "Issuing instruction PC %#x [sn:%lli].\n", 529 inst->readPC(), inst->seqNum); 530 531 depPred.issued(inst->readPC(), inst->seqNum, inst->isStore()); 532} 533 534template <class MemDepPred, class Impl> 535inline typename MemDepUnit<MemDepPred,Impl>::MemDepEntryPtr & 536MemDepUnit<MemDepPred, Impl>::findInHash(const DynInstPtr &inst) 537{ 538 MemDepHashIt hash_it = memDepHash.find(inst->seqNum); 539 540 assert(hash_it != memDepHash.end()); 541 542 return (*hash_it).second; 543} 544 545template <class MemDepPred, class Impl> 546inline void 547MemDepUnit<MemDepPred, Impl>::moveToReady(MemDepEntryPtr &woken_inst_entry) 548{ 549 DPRINTF(MemDepUnit, "Adding instruction [sn:%lli] " 550 "to the ready list.\n", woken_inst_entry->inst->seqNum); 551 552 assert(!woken_inst_entry->squashed); 553 554 iqPtr->addReadyMemInst(woken_inst_entry->inst); 555} 556 557 558template <class MemDepPred, class Impl> 559void 560MemDepUnit<MemDepPred, Impl>::dumpLists() 561{ 562 for (unsigned tid=0; tid < Impl::MaxThreads; tid++) { 563 cprintf("Instruction list %i size: %i\n", 564 tid, instList[tid].size()); 565 566 ListIt inst_list_it = instList[tid].begin(); 567 int num = 0; 568 569 while (inst_list_it != instList[tid].end()) { 570 cprintf("Instruction:%i\nPC:%#x\n[sn:%i]\n[tid:%i]\nIssued:%i\n" 571 "Squashed:%i\n\n", 572 num, (*inst_list_it)->readPC(), 573 (*inst_list_it)->seqNum, 574 (*inst_list_it)->threadNumber, 575 (*inst_list_it)->isIssued(), 576 (*inst_list_it)->isSquashed()); 577 inst_list_it++; 578 ++num; 579 } 580 } 581 582 cprintf("Memory dependence hash size: %i\n", memDepHash.size()); 583 584#ifdef DEBUG 585 cprintf("Memory dependence entries: %i\n", MemDepEntry::memdep_count); 586#endif 587} 588