base.hh revision 8834
1/* 2 * Copyright (c) 2003-2005 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: Erik Hallnor 29 * Steve Reinhardt 30 * Ron Dreslinski 31 */ 32 33/** 34 * @file 35 * Declares a basic cache interface BaseCache. 36 */ 37 38#ifndef __BASE_CACHE_HH__ 39#define __BASE_CACHE_HH__ 40 41#include <algorithm> 42#include <list> 43#include <string> 44#include <vector> 45 46#include "base/misc.hh" 47#include "base/statistics.hh" 48#include "base/trace.hh" 49#include "base/types.hh" 50#include "debug/Cache.hh" 51#include "debug/CachePort.hh" 52#include "mem/cache/mshr_queue.hh" 53#include "mem/mem_object.hh" 54#include "mem/packet.hh" 55#include "mem/request.hh" 56#include "mem/tport.hh" 57#include "params/BaseCache.hh" 58#include "sim/eventq.hh" 59#include "sim/full_system.hh" 60#include "sim/sim_exit.hh" 61#include "sim/system.hh" 62 63class MSHR; 64/** 65 * A basic cache interface. Implements some common functions for speed. 66 */ 67class BaseCache : public MemObject 68{ 69 /** 70 * Indexes to enumerate the MSHR queues. 71 */ 72 enum MSHRQueueIndex { 73 MSHRQueue_MSHRs, 74 MSHRQueue_WriteBuffer 75 }; 76 77 public: 78 /** 79 * Reasons for caches to be blocked. 80 */ 81 enum BlockedCause { 82 Blocked_NoMSHRs = MSHRQueue_MSHRs, 83 Blocked_NoWBBuffers = MSHRQueue_WriteBuffer, 84 Blocked_NoTargets, 85 NUM_BLOCKED_CAUSES 86 }; 87 88 /** 89 * Reasons for cache to request a bus. 90 */ 91 enum RequestCause { 92 Request_MSHR = MSHRQueue_MSHRs, 93 Request_WB = MSHRQueue_WriteBuffer, 94 Request_PF, 95 NUM_REQUEST_CAUSES 96 }; 97 98 protected: 99 100 class CachePort : public SimpleTimingPort 101 { 102 public: 103 BaseCache *cache; 104 105 protected: 106 CachePort(const std::string &_name, BaseCache *_cache, 107 const std::string &_label); 108 109 virtual unsigned deviceBlockSize() const; 110 111 bool recvRetryCommon(); 112 113 typedef EventWrapper<Port, &Port::sendRetry> 114 SendRetryEvent; 115 116 const std::string label; 117 118 public: 119 void setBlocked(); 120 121 void clearBlocked(); 122 123 bool checkFunctional(PacketPtr pkt); 124 125 bool blocked; 126 127 bool mustSendRetry; 128 129 void requestBus(RequestCause cause, Tick time) 130 { 131 DPRINTF(CachePort, "Asserting bus request for cause %d\n", cause); 132 if (!waitingOnRetry) { 133 schedSendEvent(time); 134 } 135 } 136 137 void respond(PacketPtr pkt, Tick time) { 138 schedSendTiming(pkt, time); 139 } 140 }; 141 142 CachePort *cpuSidePort; 143 CachePort *memSidePort; 144 145 protected: 146 147 /** Miss status registers */ 148 MSHRQueue mshrQueue; 149 150 /** Write/writeback buffer */ 151 MSHRQueue writeBuffer; 152 153 MSHR *allocateBufferInternal(MSHRQueue *mq, Addr addr, int size, 154 PacketPtr pkt, Tick time, bool requestBus) 155 { 156 MSHR *mshr = mq->allocate(addr, size, pkt, time, order++); 157 158 if (mq->isFull()) { 159 setBlocked((BlockedCause)mq->index); 160 } 161 162 if (requestBus) { 163 requestMemSideBus((RequestCause)mq->index, time); 164 } 165 166 return mshr; 167 } 168 169 void markInServiceInternal(MSHR *mshr, PacketPtr pkt) 170 { 171 MSHRQueue *mq = mshr->queue; 172 bool wasFull = mq->isFull(); 173 mq->markInService(mshr, pkt); 174 if (wasFull && !mq->isFull()) { 175 clearBlocked((BlockedCause)mq->index); 176 } 177 } 178 179 /** Block size of this cache */ 180 const unsigned blkSize; 181 182 /** 183 * The latency of a hit in this device. 184 */ 185 int hitLatency; 186 187 /** The number of targets for each MSHR. */ 188 const int numTarget; 189 190 /** Do we forward snoops from mem side port through to cpu side port? */ 191 bool forwardSnoops; 192 193 /** Is this cache a toplevel cache (e.g. L1, I/O cache). If so we should 194 * never try to forward ownership and similar optimizations to the cpu 195 * side */ 196 bool isTopLevel; 197 198 /** 199 * Bit vector of the blocking reasons for the access path. 200 * @sa #BlockedCause 201 */ 202 uint8_t blocked; 203 204 /** Increasing order number assigned to each incoming request. */ 205 uint64_t order; 206 207 /** Stores time the cache blocked for statistics. */ 208 Tick blockedCycle; 209 210 /** Pointer to the MSHR that has no targets. */ 211 MSHR *noTargetMSHR; 212 213 /** The number of misses to trigger an exit event. */ 214 Counter missCount; 215 216 /** The drain event. */ 217 Event *drainEvent; 218 219 /** 220 * The address range to which the cache responds on the CPU side. 221 * Normally this is all possible memory addresses. */ 222 Range<Addr> addrRange; 223 224 public: 225 /** System we are currently operating in. */ 226 System *system; 227 228 // Statistics 229 /** 230 * @addtogroup CacheStatistics 231 * @{ 232 */ 233 234 /** Number of hits per thread for each type of command. @sa Packet::Command */ 235 Stats::Vector hits[MemCmd::NUM_MEM_CMDS]; 236 /** Number of hits for demand accesses. */ 237 Stats::Formula demandHits; 238 /** Number of hit for all accesses. */ 239 Stats::Formula overallHits; 240 241 /** Number of misses per thread for each type of command. @sa Packet::Command */ 242 Stats::Vector misses[MemCmd::NUM_MEM_CMDS]; 243 /** Number of misses for demand accesses. */ 244 Stats::Formula demandMisses; 245 /** Number of misses for all accesses. */ 246 Stats::Formula overallMisses; 247 248 /** 249 * Total number of cycles per thread/command spent waiting for a miss. 250 * Used to calculate the average miss latency. 251 */ 252 Stats::Vector missLatency[MemCmd::NUM_MEM_CMDS]; 253 /** Total number of cycles spent waiting for demand misses. */ 254 Stats::Formula demandMissLatency; 255 /** Total number of cycles spent waiting for all misses. */ 256 Stats::Formula overallMissLatency; 257 258 /** The number of accesses per command and thread. */ 259 Stats::Formula accesses[MemCmd::NUM_MEM_CMDS]; 260 /** The number of demand accesses. */ 261 Stats::Formula demandAccesses; 262 /** The number of overall accesses. */ 263 Stats::Formula overallAccesses; 264 265 /** The miss rate per command and thread. */ 266 Stats::Formula missRate[MemCmd::NUM_MEM_CMDS]; 267 /** The miss rate of all demand accesses. */ 268 Stats::Formula demandMissRate; 269 /** The miss rate for all accesses. */ 270 Stats::Formula overallMissRate; 271 272 /** The average miss latency per command and thread. */ 273 Stats::Formula avgMissLatency[MemCmd::NUM_MEM_CMDS]; 274 /** The average miss latency for demand misses. */ 275 Stats::Formula demandAvgMissLatency; 276 /** The average miss latency for all misses. */ 277 Stats::Formula overallAvgMissLatency; 278 279 /** The total number of cycles blocked for each blocked cause. */ 280 Stats::Vector blocked_cycles; 281 /** The number of times this cache blocked for each blocked cause. */ 282 Stats::Vector blocked_causes; 283 284 /** The average number of cycles blocked for each blocked cause. */ 285 Stats::Formula avg_blocked; 286 287 /** The number of fast writes (WH64) performed. */ 288 Stats::Scalar fastWrites; 289 290 /** The number of cache copies performed. */ 291 Stats::Scalar cacheCopies; 292 293 /** Number of blocks written back per thread. */ 294 Stats::Vector writebacks; 295 296 /** Number of misses that hit in the MSHRs per command and thread. */ 297 Stats::Vector mshr_hits[MemCmd::NUM_MEM_CMDS]; 298 /** Demand misses that hit in the MSHRs. */ 299 Stats::Formula demandMshrHits; 300 /** Total number of misses that hit in the MSHRs. */ 301 Stats::Formula overallMshrHits; 302 303 /** Number of misses that miss in the MSHRs, per command and thread. */ 304 Stats::Vector mshr_misses[MemCmd::NUM_MEM_CMDS]; 305 /** Demand misses that miss in the MSHRs. */ 306 Stats::Formula demandMshrMisses; 307 /** Total number of misses that miss in the MSHRs. */ 308 Stats::Formula overallMshrMisses; 309 310 /** Number of misses that miss in the MSHRs, per command and thread. */ 311 Stats::Vector mshr_uncacheable[MemCmd::NUM_MEM_CMDS]; 312 /** Total number of misses that miss in the MSHRs. */ 313 Stats::Formula overallMshrUncacheable; 314 315 /** Total cycle latency of each MSHR miss, per command and thread. */ 316 Stats::Vector mshr_miss_latency[MemCmd::NUM_MEM_CMDS]; 317 /** Total cycle latency of demand MSHR misses. */ 318 Stats::Formula demandMshrMissLatency; 319 /** Total cycle latency of overall MSHR misses. */ 320 Stats::Formula overallMshrMissLatency; 321 322 /** Total cycle latency of each MSHR miss, per command and thread. */ 323 Stats::Vector mshr_uncacheable_lat[MemCmd::NUM_MEM_CMDS]; 324 /** Total cycle latency of overall MSHR misses. */ 325 Stats::Formula overallMshrUncacheableLatency; 326 327#if 0 328 /** The total number of MSHR accesses per command and thread. */ 329 Stats::Formula mshrAccesses[MemCmd::NUM_MEM_CMDS]; 330 /** The total number of demand MSHR accesses. */ 331 Stats::Formula demandMshrAccesses; 332 /** The total number of MSHR accesses. */ 333 Stats::Formula overallMshrAccesses; 334#endif 335 336 /** The miss rate in the MSHRs pre command and thread. */ 337 Stats::Formula mshrMissRate[MemCmd::NUM_MEM_CMDS]; 338 /** The demand miss rate in the MSHRs. */ 339 Stats::Formula demandMshrMissRate; 340 /** The overall miss rate in the MSHRs. */ 341 Stats::Formula overallMshrMissRate; 342 343 /** The average latency of an MSHR miss, per command and thread. */ 344 Stats::Formula avgMshrMissLatency[MemCmd::NUM_MEM_CMDS]; 345 /** The average latency of a demand MSHR miss. */ 346 Stats::Formula demandAvgMshrMissLatency; 347 /** The average overall latency of an MSHR miss. */ 348 Stats::Formula overallAvgMshrMissLatency; 349 350 /** The average latency of an MSHR miss, per command and thread. */ 351 Stats::Formula avgMshrUncacheableLatency[MemCmd::NUM_MEM_CMDS]; 352 /** The average overall latency of an MSHR miss. */ 353 Stats::Formula overallAvgMshrUncacheableLatency; 354 355 /** The number of times a thread hit its MSHR cap. */ 356 Stats::Vector mshr_cap_events; 357 /** The number of times software prefetches caused the MSHR to block. */ 358 Stats::Vector soft_prefetch_mshr_full; 359 360 Stats::Scalar mshr_no_allocate_misses; 361 362 /** 363 * @} 364 */ 365 366 /** 367 * Register stats for this object. 368 */ 369 virtual void regStats(); 370 371 public: 372 typedef BaseCacheParams Params; 373 BaseCache(const Params *p); 374 ~BaseCache() {} 375 376 virtual void init(); 377 378 /** 379 * Query block size of a cache. 380 * @return The block size 381 */ 382 unsigned 383 getBlockSize() const 384 { 385 return blkSize; 386 } 387 388 389 Addr blockAlign(Addr addr) const { return (addr & ~(Addr(blkSize - 1))); } 390 391 392 const Range<Addr> &getAddrRange() const { return addrRange; } 393 394 MSHR *allocateMissBuffer(PacketPtr pkt, Tick time, bool requestBus) 395 { 396 assert(!pkt->req->isUncacheable()); 397 return allocateBufferInternal(&mshrQueue, 398 blockAlign(pkt->getAddr()), blkSize, 399 pkt, time, requestBus); 400 } 401 402 MSHR *allocateWriteBuffer(PacketPtr pkt, Tick time, bool requestBus) 403 { 404 assert(pkt->isWrite() && !pkt->isRead()); 405 return allocateBufferInternal(&writeBuffer, 406 pkt->getAddr(), pkt->getSize(), 407 pkt, time, requestBus); 408 } 409 410 MSHR *allocateUncachedReadBuffer(PacketPtr pkt, Tick time, bool requestBus) 411 { 412 assert(pkt->req->isUncacheable()); 413 assert(pkt->isRead()); 414 return allocateBufferInternal(&mshrQueue, 415 pkt->getAddr(), pkt->getSize(), 416 pkt, time, requestBus); 417 } 418 419 /** 420 * Returns true if the cache is blocked for accesses. 421 */ 422 bool isBlocked() 423 { 424 return blocked != 0; 425 } 426 427 /** 428 * Marks the access path of the cache as blocked for the given cause. This 429 * also sets the blocked flag in the slave interface. 430 * @param cause The reason for the cache blocking. 431 */ 432 void setBlocked(BlockedCause cause) 433 { 434 uint8_t flag = 1 << cause; 435 if (blocked == 0) { 436 blocked_causes[cause]++; 437 blockedCycle = curTick(); 438 cpuSidePort->setBlocked(); 439 } 440 blocked |= flag; 441 DPRINTF(Cache,"Blocking for cause %d, mask=%d\n", cause, blocked); 442 } 443 444 /** 445 * Marks the cache as unblocked for the given cause. This also clears the 446 * blocked flags in the appropriate interfaces. 447 * @param cause The newly unblocked cause. 448 * @warning Calling this function can cause a blocked request on the bus to 449 * access the cache. The cache must be in a state to handle that request. 450 */ 451 void clearBlocked(BlockedCause cause) 452 { 453 uint8_t flag = 1 << cause; 454 blocked &= ~flag; 455 DPRINTF(Cache,"Unblocking for cause %d, mask=%d\n", cause, blocked); 456 if (blocked == 0) { 457 blocked_cycles[cause] += curTick() - blockedCycle; 458 cpuSidePort->clearBlocked(); 459 } 460 } 461 462 /** 463 * Request the master bus for the given cause and time. 464 * @param cause The reason for the request. 465 * @param time The time to make the request. 466 */ 467 void requestMemSideBus(RequestCause cause, Tick time) 468 { 469 memSidePort->requestBus(cause, time); 470 } 471 472 /** 473 * Clear the master bus request for the given cause. 474 * @param cause The request reason to clear. 475 */ 476 void deassertMemSideBusRequest(RequestCause cause) 477 { 478 // Obsolete... we no longer signal bus requests explicitly so 479 // we can't deassert them. Leaving this in as a no-op since 480 // the prefetcher calls it to indicate that it no longer wants 481 // to request a prefetch, and someday that might be 482 // interesting again. 483 } 484 485 virtual unsigned int drain(Event *de); 486 487 virtual bool inCache(Addr addr) = 0; 488 489 virtual bool inMissQueue(Addr addr) = 0; 490 491 void incMissCount(PacketPtr pkt) 492 { 493 assert(pkt->req->masterId() < system->maxMasters()); 494 misses[pkt->cmdToIndex()][pkt->req->masterId()]++; 495 496 if (missCount) { 497 --missCount; 498 if (missCount == 0) 499 exitSimLoop("A cache reached the maximum miss count"); 500 } 501 } 502 void incHitCount(PacketPtr pkt) 503 { 504 assert(pkt->req->masterId() < system->maxMasters()); 505 hits[pkt->cmdToIndex()][pkt->req->masterId()]++; 506 507 } 508 509}; 510 511#endif //__BASE_CACHE_HH__ 512