cache.hh revision 3135
1/* 2 * Copyright (c) 2002-2005 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 * Dave Greene 30 * Steve Reinhardt 31 */ 32 33/** 34 * @file 35 * Describes a cache based on template policies. 36 */ 37 38#ifndef __CACHE_HH__ 39#define __CACHE_HH__ 40 41#include "base/misc.hh" // fatal, panic, and warn 42#include "cpu/smt.hh" // SMT_MAX_THREADS 43 44#include "mem/cache/base_cache.hh" 45#include "mem/cache/prefetch/prefetcher.hh" 46 47//Forward decleration 48class MSHR; 49 50 51/** 52 * A template-policy based cache. The behavior of the cache can be altered by 53 * supplying different template policies. TagStore handles all tag and data 54 * storage @sa TagStore. Buffering handles all misses and writes/writebacks 55 * @sa MissQueue. Coherence handles all coherence policy details @sa 56 * UniCoherence, SimpleMultiCoherence. 57 */ 58template <class TagStore, class Buffering, class Coherence> 59class Cache : public BaseCache 60{ 61 public: 62 /** Define the type of cache block to use. */ 63 typedef typename TagStore::BlkType BlkType; 64 65 bool prefetchAccess; 66 protected: 67 68 /** Tag and data Storage */ 69 TagStore *tags; 70 /** Miss and Writeback handler */ 71 Buffering *missQueue; 72 /** Coherence protocol. */ 73 Coherence *coherence; 74 75 /** Prefetcher */ 76 Prefetcher<TagStore, Buffering> *prefetcher; 77 78 /** Do fast copies in this cache. */ 79 bool doCopy; 80 81 /** Block on a delayed copy. */ 82 bool blockOnCopy; 83 84 /** 85 * The clock ratio of the outgoing bus. 86 * Used for calculating critical word first. 87 */ 88 int busRatio; 89 90 /** 91 * The bus width in bytes of the outgoing bus. 92 * Used for calculating critical word first. 93 */ 94 int busWidth; 95 96 /** 97 * The latency of a hit in this device. 98 */ 99 int hitLatency; 100 101 /** 102 * A permanent mem req to always be used to cause invalidations. 103 * Used to append to target list, to cause an invalidation. 104 */ 105 Packet * invalidatePkt; 106 107 /** 108 * Temporarily move a block into a MSHR. 109 * @todo Remove this when LSQ/SB are fixed and implemented in memtest. 110 */ 111 void pseudoFill(Addr addr); 112 113 /** 114 * Temporarily move a block into an existing MSHR. 115 * @todo Remove this when LSQ/SB are fixed and implemented in memtest. 116 */ 117 void pseudoFill(MSHR *mshr); 118 119 public: 120 121 class Params 122 { 123 public: 124 TagStore *tags; 125 Buffering *missQueue; 126 Coherence *coherence; 127 bool doCopy; 128 bool blockOnCopy; 129 BaseCache::Params baseParams; 130 Prefetcher<TagStore, Buffering> *prefetcher; 131 bool prefetchAccess; 132 int hitLatency; 133 134 Params(TagStore *_tags, Buffering *mq, Coherence *coh, 135 bool do_copy, BaseCache::Params params, 136 Prefetcher<TagStore, Buffering> *_prefetcher, 137 bool prefetch_access, int hit_latency) 138 : tags(_tags), missQueue(mq), coherence(coh), doCopy(do_copy), 139 blockOnCopy(false), baseParams(params), 140 prefetcher(_prefetcher), prefetchAccess(prefetch_access), 141 hitLatency(hit_latency) 142 { 143 } 144 }; 145 146 /** Instantiates a basic cache object. */ 147 Cache(const std::string &_name, Params ¶ms); 148 149 virtual bool doTimingAccess(Packet *pkt, CachePort *cachePort, 150 bool isCpuSide); 151 152 virtual Tick doAtomicAccess(Packet *pkt, bool isCpuSide); 153 154 virtual void doFunctionalAccess(Packet *pkt, bool isCpuSide); 155 156 virtual void recvStatusChange(Port::Status status, bool isCpuSide); 157 158 void regStats(); 159 160 /** 161 * Performs the access specified by the request. 162 * @param pkt The request to perform. 163 * @return The result of the access. 164 */ 165 bool access(Packet * &pkt); 166 167 /** 168 * Selects a request to send on the bus. 169 * @return The memory request to service. 170 */ 171 virtual Packet * getPacket(); 172 173 /** 174 * Was the request was sent successfully? 175 * @param pkt The request. 176 * @param success True if the request was sent successfully. 177 */ 178 virtual void sendResult(Packet * &pkt, bool success); 179 180 /** 181 * Handles a response (cache line fill/write ack) from the bus. 182 * @param pkt The request being responded to. 183 */ 184 void handleResponse(Packet * &pkt); 185 186 /** 187 * Start handling a copy transaction. 188 * @param pkt The copy request to perform. 189 */ 190 void startCopy(Packet * &pkt); 191 192 /** 193 * Handle a delayed copy transaction. 194 * @param pkt The delayed copy request to continue. 195 * @param addr The address being responded to. 196 * @param blk The block of the current response. 197 * @param mshr The mshr being handled. 198 */ 199 void handleCopy(Packet * &pkt, Addr addr, BlkType *blk, MSHR *mshr); 200 201 /** 202 * Selects a coherence message to forward to lower levels of the hierarchy. 203 * @return The coherence message to forward. 204 */ 205 virtual Packet * getCoherencePacket(); 206 207 /** 208 * Snoops bus transactions to maintain coherence. 209 * @param pkt The current bus transaction. 210 */ 211 void snoop(Packet * &pkt); 212 213 void snoopResponse(Packet * &pkt); 214 215 /** 216 * Invalidates the block containing address if found. 217 * @param addr The address to look for. 218 * @param asid The address space ID of the address. 219 * @todo Is this function necessary? 220 */ 221 void invalidateBlk(Addr addr); 222 223 /** 224 * Squash all requests associated with specified thread. 225 * intended for use by I-cache. 226 * @param threadNum The thread to squash. 227 */ 228 void squash(int threadNum) 229 { 230 missQueue->squash(threadNum); 231 } 232 233 /** 234 * Return the number of outstanding misses in a Cache. 235 * Default returns 0. 236 * 237 * @retval unsigned The number of missing still outstanding. 238 */ 239 unsigned outstandingMisses() const 240 { 241 return missQueue->getMisses(); 242 } 243 244 /** 245 * Perform the access specified in the request and return the estimated 246 * time of completion. This function can either update the hierarchy state 247 * or just perform the access wherever the data is found depending on the 248 * state of the update flag. 249 * @param pkt The memory request to satisfy 250 * @param update If true, update the hierarchy, otherwise just perform the 251 * request. 252 * @return The estimated completion time. 253 */ 254 Tick probe(Packet * &pkt, bool update, CachePort * otherSidePort); 255 256 /** 257 * Snoop for the provided request in the cache and return the estimated 258 * time of completion. 259 * @todo Can a snoop probe not change state? 260 * @param pkt The memory request to satisfy 261 * @param update If true, update the hierarchy, otherwise just perform the 262 * request. 263 * @return The estimated completion time. 264 */ 265 Tick snoopProbe(Packet * &pkt); 266}; 267 268#endif // __CACHE_HH__ 269