cache.hh revision 2812
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 declarations 48class Bus; 49 50/** 51 * A template-policy based cache. The behavior of the cache can be altered by 52 * supplying different template policies. TagStore handles all tag and data 53 * storage @sa TagStore. Buffering handles all misses and writes/writebacks 54 * @sa MissQueue. Coherence handles all coherence policy details @sa 55 * UniCoherence, SimpleMultiCoherence. 56 */ 57template <class TagStore, class Buffering, class Coherence> 58class Cache : public BaseCache 59{ 60 public: 61 /** Define the type of cache block to use. */ 62 typedef typename TagStore::BlkType BlkType; 63 64 bool prefetchAccess; 65 protected: 66 67 /** Tag and data Storage */ 68 TagStore *tags; 69 /** Miss and Writeback handler */ 70 Buffering *missQueue; 71 /** Coherence protocol. */ 72 Coherence *coherence; 73 74 /** Prefetcher */ 75 Prefetcher<TagStore, Buffering> *prefetcher; 76 77 /** Do fast copies in this cache. */ 78 bool doCopy; 79 80 /** Block on a delayed copy. */ 81 bool blockOnCopy; 82 83 /** 84 * The clock ratio of the outgoing bus. 85 * Used for calculating critical word first. 86 */ 87 int busRatio; 88 89 /** 90 * The bus width in bytes of the outgoing bus. 91 * Used for calculating critical word first. 92 */ 93 int busWidth; 94 95 /** 96 * A permanent mem req to always be used to cause invalidations. 97 * Used to append to target list, to cause an invalidation. 98 */ 99 Packet * invalidatePkt; 100 101 /** 102 * Temporarily move a block into a MSHR. 103 * @todo Remove this when LSQ/SB are fixed and implemented in memtest. 104 */ 105 void pseudoFill(Addr addr, int asid); 106 107 /** 108 * Temporarily move a block into an existing MSHR. 109 * @todo Remove this when LSQ/SB are fixed and implemented in memtest. 110 */ 111 void pseudoFill(MSHR *mshr); 112 113 public: 114 115 class Params 116 { 117 public: 118 TagStore *tags; 119 Buffering *missQueue; 120 Coherence *coherence; 121 bool doCopy; 122 bool blockOnCopy; 123 BaseCache::Params baseParams; 124 Bus *in; 125 Bus *out; 126 Prefetcher<TagStore, Buffering> *prefetcher; 127 bool prefetchAccess; 128 129 Params(TagStore *_tags, Buffering *mq, Coherence *coh, 130 bool do_copy, BaseCache::Params params, Bus * in_bus, 131 Bus * out_bus, Prefetcher<TagStore, Buffering> *_prefetcher, 132 bool prefetch_access) 133 : tags(_tags), missQueue(mq), coherence(coh), doCopy(do_copy), 134 blockOnCopy(false), baseParams(params), in(in_bus), out(out_bus), 135 prefetcher(_prefetcher), prefetchAccess(prefetch_access) 136 { 137 } 138 }; 139 140 /** Instantiates a basic cache object. */ 141 Cache(const std::string &_name, Params ¶ms); 142 143 void regStats(); 144 145 /** 146 * Performs the access specified by the request. 147 * @param req The request to perform. 148 * @return The result of the access. 149 */ 150 bool access(Packet * &pkt); 151 152 /** 153 * Selects a request to send on the bus. 154 * @return The memory request to service. 155 */ 156 Packet * getPacket(); 157 158 /** 159 * Was the request was sent successfully? 160 * @param req The request. 161 * @param success True if the request was sent successfully. 162 */ 163 void sendResult(Packet * &pkt, bool success); 164 165 /** 166 * Handles a response (cache line fill/write ack) from the bus. 167 * @param req The request being responded to. 168 */ 169 void handleResponse(Packet * &pkt); 170 171 /** 172 * Start handling a copy transaction. 173 * @param req The copy request to perform. 174 */ 175 void startCopy(Packet * &pkt); 176 177 /** 178 * Handle a delayed copy transaction. 179 * @param req The delayed copy request to continue. 180 * @param addr The address being responded to. 181 * @param blk The block of the current response. 182 * @param mshr The mshr being handled. 183 */ 184 void handleCopy(Packet * &pkt, Addr addr, BlkType *blk, MSHR *mshr); 185 186 /** 187 * Selects a coherence message to forward to lower levels of the hierarchy. 188 * @return The coherence message to forward. 189 */ 190 Packet * getCoherenceReq(); 191 192 /** 193 * Snoops bus transactions to maintain coherence. 194 * @param req The current bus transaction. 195 */ 196 void snoop(Packet * &pkt); 197 198 void snoopResponse(Packet * &pkt); 199 200 /** 201 * Invalidates the block containing address if found. 202 * @param addr The address to look for. 203 * @param asid The address space ID of the address. 204 * @todo Is this function necessary? 205 */ 206 void invalidateBlk(Addr addr, int asid); 207 208 /** 209 * Aquash all requests associated with specified thread. 210 * intended for use by I-cache. 211 * @param req->getThreadNum()ber The thread to squash. 212 */ 213 void squash(int threadNum) 214 { 215 missQueue->squash(threadNum); 216 } 217 218 /** 219 * Return the number of outstanding misses in a Cache. 220 * Default returns 0. 221 * 222 * @retval unsigned The number of missing still outstanding. 223 */ 224 unsigned outstandingMisses() const 225 { 226 return missQueue->getMisses(); 227 } 228 229 /** 230 * Send a response to the slave interface. 231 * @param req The request being responded to. 232 * @param time The time the response is ready. 233 */ 234 void respond(Packet * &pkt, Tick time) 235 { 236 //si->respond(pkt,time); 237 cpuSidePort->sendAtomic(pkt); 238 } 239 240 /** 241 * Perform the access specified in the request and return the estimated 242 * time of completion. This function can either update the hierarchy state 243 * or just perform the access wherever the data is found depending on the 244 * state of the update flag. 245 * @param req The memory request to satisfy 246 * @param update If true, update the hierarchy, otherwise just perform the 247 * request. 248 * @return The estimated completion time. 249 */ 250 Tick probe(Packet * &pkt, bool update); 251 252 /** 253 * Snoop for the provided request in the cache and return the estimated 254 * time of completion. 255 * @todo Can a snoop probe not change state? 256 * @param req The memory request to satisfy 257 * @param update If true, update the hierarchy, otherwise just perform the 258 * request. 259 * @return The estimated completion time. 260 */ 261 Tick snoopProbe(Packet * &pkt, bool update); 262}; 263 264#endif // __CACHE_HH__ 265