fa_lru.cc revision 11055:54071fd5c397
1/* 2 * Copyright (c) 2013 ARM Limited 3 * All rights reserved. 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2003-2005 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Erik Hallnor 41 */ 42 43/** 44 * @file 45 * Definitions a fully associative LRU tagstore. 46 */ 47 48#include <cassert> 49#include <sstream> 50 51#include "base/intmath.hh" 52#include "base/misc.hh" 53#include "mem/cache/tags/fa_lru.hh" 54 55using namespace std; 56 57FALRU::FALRU(const Params *p) 58 : BaseTags(p), cacheBoundaries(nullptr) 59{ 60 if (!isPowerOf2(blkSize)) 61 fatal("cache block size (in bytes) `%d' must be a power of two", 62 blkSize); 63 if (!isPowerOf2(size)) 64 fatal("Cache Size must be power of 2 for now"); 65 66 // Track all cache sizes from 128K up by powers of 2 67 numCaches = floorLog2(size) - 17; 68 if (numCaches >0){ 69 cacheBoundaries = new FALRUBlk *[numCaches]; 70 cacheMask = (1 << numCaches) - 1; 71 } else { 72 cacheMask = 0; 73 } 74 75 warmupBound = size/blkSize; 76 numBlocks = size/blkSize; 77 78 blks = new FALRUBlk[numBlocks]; 79 head = &(blks[0]); 80 tail = &(blks[numBlocks-1]); 81 82 head->prev = NULL; 83 head->next = &(blks[1]); 84 head->inCache = cacheMask; 85 86 tail->prev = &(blks[numBlocks-2]); 87 tail->next = NULL; 88 tail->inCache = 0; 89 90 unsigned index = (1 << 17) / blkSize; 91 unsigned j = 0; 92 int flags = cacheMask; 93 for (unsigned i = 1; i < numBlocks - 1; i++) { 94 blks[i].inCache = flags; 95 if (i == index - 1){ 96 cacheBoundaries[j] = &(blks[i]); 97 flags &= ~ (1<<j); 98 ++j; 99 index = index << 1; 100 } 101 blks[i].prev = &(blks[i-1]); 102 blks[i].next = &(blks[i+1]); 103 blks[i].isTouched = false; 104 blks[i].set = 0; 105 blks[i].way = i; 106 } 107 assert(j == numCaches); 108 assert(index == numBlocks); 109 //assert(check()); 110} 111 112FALRU::~FALRU() 113{ 114 if (numCaches) 115 delete[] cacheBoundaries; 116 117 delete[] blks; 118} 119 120void 121FALRU::regStats() 122{ 123 using namespace Stats; 124 BaseTags::regStats(); 125 hits 126 .init(numCaches+1) 127 .name(name() + ".falru_hits") 128 .desc("The number of hits in each cache size.") 129 ; 130 misses 131 .init(numCaches+1) 132 .name(name() + ".falru_misses") 133 .desc("The number of misses in each cache size.") 134 ; 135 accesses 136 .name(name() + ".falru_accesses") 137 .desc("The number of accesses to the FA LRU cache.") 138 ; 139 140 for (unsigned i = 0; i <= numCaches; ++i) { 141 stringstream size_str; 142 if (i < 3){ 143 size_str << (1<<(i+7)) <<"K"; 144 } else { 145 size_str << (1<<(i-3)) <<"M"; 146 } 147 148 hits.subname(i, size_str.str()); 149 hits.subdesc(i, "Hits in a " + size_str.str() +" cache"); 150 misses.subname(i, size_str.str()); 151 misses.subdesc(i, "Misses in a " + size_str.str() +" cache"); 152 } 153} 154 155FALRUBlk * 156FALRU::hashLookup(Addr addr) const 157{ 158 tagIterator iter = tagHash.find(addr); 159 if (iter != tagHash.end()) { 160 return (*iter).second; 161 } 162 return NULL; 163} 164 165void 166FALRU::invalidate(CacheBlk *blk) 167{ 168 assert(blk); 169 tagsInUse--; 170} 171 172CacheBlk* 173FALRU::accessBlock(Addr addr, bool is_secure, Cycles &lat, int context_src) 174{ 175 return accessBlock(addr, is_secure, lat, context_src, 0); 176} 177 178CacheBlk* 179FALRU::accessBlock(Addr addr, bool is_secure, Cycles &lat, int context_src, 180 int *inCache) 181{ 182 accesses++; 183 int tmp_in_cache = 0; 184 Addr blkAddr = blkAlign(addr); 185 FALRUBlk* blk = hashLookup(blkAddr); 186 187 if (blk && blk->isValid()) { 188 assert(blk->tag == blkAddr); 189 tmp_in_cache = blk->inCache; 190 for (unsigned i = 0; i < numCaches; i++) { 191 if (1<<i & blk->inCache) { 192 hits[i]++; 193 } else { 194 misses[i]++; 195 } 196 } 197 hits[numCaches]++; 198 if (blk != head){ 199 moveToHead(blk); 200 } 201 } else { 202 blk = NULL; 203 for (unsigned i = 0; i <= numCaches; ++i) { 204 misses[i]++; 205 } 206 } 207 if (inCache) { 208 *inCache = tmp_in_cache; 209 } 210 211 lat = accessLatency; 212 //assert(check()); 213 return blk; 214} 215 216 217CacheBlk* 218FALRU::findBlock(Addr addr, bool is_secure) const 219{ 220 Addr blkAddr = blkAlign(addr); 221 FALRUBlk* blk = hashLookup(blkAddr); 222 223 if (blk && blk->isValid()) { 224 assert(blk->tag == blkAddr); 225 } else { 226 blk = NULL; 227 } 228 return blk; 229} 230 231CacheBlk* 232FALRU::findBlockBySetAndWay(int set, int way) const 233{ 234 assert(set == 0); 235 return &blks[way]; 236} 237 238CacheBlk* 239FALRU::findVictim(Addr addr) 240{ 241 FALRUBlk * blk = tail; 242 assert(blk->inCache == 0); 243 moveToHead(blk); 244 tagHash.erase(blk->tag); 245 tagHash[blkAlign(addr)] = blk; 246 if (blk->isValid()) { 247 replacements[0]++; 248 } else { 249 tagsInUse++; 250 blk->isTouched = true; 251 if (!warmedUp && tagsInUse.value() >= warmupBound) { 252 warmedUp = true; 253 warmupCycle = curTick(); 254 } 255 } 256 //assert(check()); 257 return blk; 258} 259 260void 261FALRU::insertBlock(PacketPtr pkt, CacheBlk *blk) 262{ 263} 264 265void 266FALRU::moveToHead(FALRUBlk *blk) 267{ 268 int updateMask = blk->inCache ^ cacheMask; 269 for (unsigned i = 0; i < numCaches; i++){ 270 if ((1<<i) & updateMask) { 271 cacheBoundaries[i]->inCache &= ~(1<<i); 272 cacheBoundaries[i] = cacheBoundaries[i]->prev; 273 } else if (cacheBoundaries[i] == blk) { 274 cacheBoundaries[i] = blk->prev; 275 } 276 } 277 blk->inCache = cacheMask; 278 if (blk != head) { 279 if (blk == tail){ 280 assert(blk->next == NULL); 281 tail = blk->prev; 282 tail->next = NULL; 283 } else { 284 blk->prev->next = blk->next; 285 blk->next->prev = blk->prev; 286 } 287 blk->next = head; 288 blk->prev = NULL; 289 head->prev = blk; 290 head = blk; 291 } 292} 293 294bool 295FALRU::check() 296{ 297 FALRUBlk* blk = head; 298 int tot_size = 0; 299 int boundary = 1<<17; 300 int j = 0; 301 int flags = cacheMask; 302 while (blk) { 303 tot_size += blkSize; 304 if (blk->inCache != flags) { 305 return false; 306 } 307 if (tot_size == boundary && blk != tail) { 308 if (cacheBoundaries[j] != blk) { 309 return false; 310 } 311 flags &=~(1 << j); 312 boundary = boundary<<1; 313 ++j; 314 } 315 blk = blk->next; 316 } 317 return true; 318} 319 320FALRU * 321FALRUParams::create() 322{ 323 return new FALRU(this); 324} 325 326