base_set_assoc.hh revision 10941
112771Sqtt2@cornell.edu/* 212771Sqtt2@cornell.edu * Copyright (c) 2012-2014 ARM Limited 312771Sqtt2@cornell.edu * All rights reserved. 412771Sqtt2@cornell.edu * 512771Sqtt2@cornell.edu * The license below extends only to copyright in the software and shall 612771Sqtt2@cornell.edu * not be construed as granting a license to any other intellectual 712771Sqtt2@cornell.edu * property including but not limited to intellectual property relating 812771Sqtt2@cornell.edu * to a hardware implementation of the functionality of the software 912771Sqtt2@cornell.edu * licensed hereunder. You may use the software subject to the license 1012771Sqtt2@cornell.edu * terms below provided that you ensure that this notice is replicated 1112771Sqtt2@cornell.edu * unmodified and in its entirety in all distributions of the software, 1212771Sqtt2@cornell.edu * modified or unmodified, in source code or in binary form. 1312771Sqtt2@cornell.edu * 1412771Sqtt2@cornell.edu * Copyright (c) 2003-2005,2014 The Regents of The University of Michigan 1512771Sqtt2@cornell.edu * All rights reserved. 1612771Sqtt2@cornell.edu * 1712771Sqtt2@cornell.edu * Redistribution and use in source and binary forms, with or without 1812771Sqtt2@cornell.edu * modification, are permitted provided that the following conditions are 1912771Sqtt2@cornell.edu * met: redistributions of source code must retain the above copyright 2012771Sqtt2@cornell.edu * notice, this list of conditions and the following disclaimer; 2112771Sqtt2@cornell.edu * redistributions in binary form must reproduce the above copyright 2212771Sqtt2@cornell.edu * notice, this list of conditions and the following disclaimer in the 2312771Sqtt2@cornell.edu * documentation and/or other materials provided with the distribution; 2412771Sqtt2@cornell.edu * neither the name of the copyright holders nor the names of its 2512771Sqtt2@cornell.edu * contributors may be used to endorse or promote products derived from 2612771Sqtt2@cornell.edu * this software without specific prior written permission. 2712771Sqtt2@cornell.edu * 2812771Sqtt2@cornell.edu * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 2912771Sqtt2@cornell.edu * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 3012771Sqtt2@cornell.edu * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 3112771Sqtt2@cornell.edu * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 3212771Sqtt2@cornell.edu * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 3312771Sqtt2@cornell.edu * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 3412771Sqtt2@cornell.edu * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 3512771Sqtt2@cornell.edu * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 3612771Sqtt2@cornell.edu * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 3712771Sqtt2@cornell.edu * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 3812771Sqtt2@cornell.edu * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 3912771Sqtt2@cornell.edu * 4012771Sqtt2@cornell.edu * Authors: Erik Hallnor 4112771Sqtt2@cornell.edu */ 4212771Sqtt2@cornell.edu 4312771Sqtt2@cornell.edu/** 4412771Sqtt2@cornell.edu * @file 4512771Sqtt2@cornell.edu * Declaration of a base set associative tag store. 4612771Sqtt2@cornell.edu */ 4712771Sqtt2@cornell.edu 4812771Sqtt2@cornell.edu#ifndef __MEM_CACHE_TAGS_BASESETASSOC_HH__ 4912771Sqtt2@cornell.edu#define __MEM_CACHE_TAGS_BASESETASSOC_HH__ 5012771Sqtt2@cornell.edu 5112771Sqtt2@cornell.edu#include <cassert> 5212771Sqtt2@cornell.edu#include <cstring> 5312771Sqtt2@cornell.edu#include <list> 5412771Sqtt2@cornell.edu 5512771Sqtt2@cornell.edu#include "mem/cache/tags/base.hh" 5612771Sqtt2@cornell.edu#include "mem/cache/tags/cacheset.hh" 5712771Sqtt2@cornell.edu#include "mem/cache/base.hh" 5812771Sqtt2@cornell.edu#include "mem/cache/blk.hh" 5912771Sqtt2@cornell.edu#include "mem/packet.hh" 6012771Sqtt2@cornell.edu#include "params/BaseSetAssoc.hh" 6112771Sqtt2@cornell.edu 6212771Sqtt2@cornell.edu/** 6312771Sqtt2@cornell.edu * A BaseSetAssoc cache tag store. 6412771Sqtt2@cornell.edu * @sa \ref gem5MemorySystem "gem5 Memory System" 6512771Sqtt2@cornell.edu * 6612771Sqtt2@cornell.edu * The BaseSetAssoc tags provide a base, as well as the functionality 6712771Sqtt2@cornell.edu * common to any set associative tags. Any derived class must implement 6812771Sqtt2@cornell.edu * the methods related to the specifics of the actual replacment policy. 6912771Sqtt2@cornell.edu * These are: 7012771Sqtt2@cornell.edu * 7112771Sqtt2@cornell.edu * BlkType* accessBlock(); 7212771Sqtt2@cornell.edu * BlkType* findVictim(); 7312771Sqtt2@cornell.edu * void insertBlock(); 7412771Sqtt2@cornell.edu * void invalidate(); 7512771Sqtt2@cornell.edu */ 7612771Sqtt2@cornell.educlass BaseSetAssoc : public BaseTags 7712771Sqtt2@cornell.edu{ 7812771Sqtt2@cornell.edu public: 7912771Sqtt2@cornell.edu /** Typedef the block type used in this tag store. */ 8012771Sqtt2@cornell.edu typedef CacheBlk BlkType; 8112771Sqtt2@cornell.edu /** Typedef for a list of pointers to the local block class. */ 8212771Sqtt2@cornell.edu typedef std::list<BlkType*> BlkList; 8312771Sqtt2@cornell.edu /** Typedef the set type used in this tag store. */ 8412771Sqtt2@cornell.edu typedef CacheSet<CacheBlk> SetType; 8512771Sqtt2@cornell.edu 8612771Sqtt2@cornell.edu 8712771Sqtt2@cornell.edu protected: 8812771Sqtt2@cornell.edu /** The associativity of the cache. */ 8912771Sqtt2@cornell.edu const unsigned assoc; 9012771Sqtt2@cornell.edu /** The allocatable associativity of the cache (alloc mask). */ 9112771Sqtt2@cornell.edu unsigned allocAssoc; 9212771Sqtt2@cornell.edu /** The number of sets in the cache. */ 9312771Sqtt2@cornell.edu const unsigned numSets; 9412771Sqtt2@cornell.edu /** Whether tags and data are accessed sequentially. */ 9512771Sqtt2@cornell.edu const bool sequentialAccess; 9612771Sqtt2@cornell.edu 9712771Sqtt2@cornell.edu /** The cache sets. */ 9812771Sqtt2@cornell.edu SetType *sets; 9912771Sqtt2@cornell.edu 10012771Sqtt2@cornell.edu /** The cache blocks. */ 10112771Sqtt2@cornell.edu BlkType *blks; 10212771Sqtt2@cornell.edu /** The data blocks, 1 per cache block. */ 10312771Sqtt2@cornell.edu uint8_t *dataBlks; 10412771Sqtt2@cornell.edu 10512771Sqtt2@cornell.edu /** The amount to shift the address to get the set. */ 10612771Sqtt2@cornell.edu int setShift; 10712771Sqtt2@cornell.edu /** The amount to shift the address to get the tag. */ 10812771Sqtt2@cornell.edu int tagShift; 10912771Sqtt2@cornell.edu /** Mask out all bits that aren't part of the set index. */ 11012771Sqtt2@cornell.edu unsigned setMask; 11112771Sqtt2@cornell.edu /** Mask out all bits that aren't part of the block offset. */ 11212771Sqtt2@cornell.edu unsigned blkMask; 11312771Sqtt2@cornell.edu 114public: 115 116 /** Convenience typedef. */ 117 typedef BaseSetAssocParams Params; 118 119 /** 120 * Construct and initialize this tag store. 121 */ 122 BaseSetAssoc(const Params *p); 123 124 /** 125 * Destructor 126 */ 127 virtual ~BaseSetAssoc(); 128 129 /** 130 * Return the block size. 131 * @return the block size. 132 */ 133 unsigned 134 getBlockSize() const 135 { 136 return blkSize; 137 } 138 139 /** 140 * Return the subblock size. In the case of BaseSetAssoc it is always 141 * the block size. 142 * @return The block size. 143 */ 144 unsigned 145 getSubBlockSize() const 146 { 147 return blkSize; 148 } 149 150 /** 151 * Return the number of sets this cache has 152 * @return The number of sets. 153 */ 154 unsigned 155 getNumSets() const 156 { 157 return numSets; 158 } 159 160 /** 161 * Return the number of ways this cache has 162 * @return The number of ways. 163 */ 164 unsigned 165 getNumWays() const 166 { 167 return assoc; 168 } 169 170 /** 171 * Find the cache block given set and way 172 * @param set The set of the block. 173 * @param way The way of the block. 174 * @return The cache block. 175 */ 176 CacheBlk *findBlockBySetAndWay(int set, int way) const; 177 178 /** 179 * Invalidate the given block. 180 * @param blk The block to invalidate. 181 */ 182 void invalidate(CacheBlk *blk) 183 { 184 assert(blk); 185 assert(blk->isValid()); 186 tagsInUse--; 187 assert(blk->srcMasterId < cache->system->maxMasters()); 188 occupancies[blk->srcMasterId]--; 189 blk->srcMasterId = Request::invldMasterId; 190 blk->task_id = ContextSwitchTaskId::Unknown; 191 blk->tickInserted = curTick(); 192 } 193 194 /** 195 * Access block and update replacement data. May not succeed, in which case 196 * NULL pointer is returned. This has all the implications of a cache 197 * access and should only be used as such. Returns the access latency as a 198 * side effect. 199 * @param addr The address to find. 200 * @param is_secure True if the target memory space is secure. 201 * @param asid The address space ID. 202 * @param lat The access latency. 203 * @return Pointer to the cache block if found. 204 */ 205 CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat, 206 int context_src) 207 { 208 Addr tag = extractTag(addr); 209 int set = extractSet(addr); 210 BlkType *blk = sets[set].findBlk(tag, is_secure); 211 lat = accessLatency;; 212 213 // Access all tags in parallel, hence one in each way. The data side 214 // either accesses all blocks in parallel, or one block sequentially on 215 // a hit. Sequential access with a miss doesn't access data. 216 tagAccesses += allocAssoc; 217 if (sequentialAccess) { 218 if (blk != NULL) { 219 dataAccesses += 1; 220 } 221 } else { 222 dataAccesses += allocAssoc; 223 } 224 225 if (blk != NULL) { 226 if (blk->whenReady > curTick() 227 && cache->ticksToCycles(blk->whenReady - curTick()) 228 > accessLatency) { 229 lat = cache->ticksToCycles(blk->whenReady - curTick()); 230 } 231 blk->refCount += 1; 232 } 233 234 return blk; 235 } 236 237 /** 238 * Finds the given address in the cache, do not update replacement data. 239 * i.e. This is a no-side-effect find of a block. 240 * @param addr The address to find. 241 * @param is_secure True if the target memory space is secure. 242 * @param asid The address space ID. 243 * @return Pointer to the cache block if found. 244 */ 245 CacheBlk* findBlock(Addr addr, bool is_secure) const; 246 247 /** 248 * Find an invalid block to evict for the address provided. 249 * If there are no invalid blocks, this will return the block 250 * in the least-recently-used position. 251 * @param addr The addr to a find a replacement candidate for. 252 * @return The candidate block. 253 */ 254 CacheBlk* findVictim(Addr addr) 255 { 256 BlkType *blk = NULL; 257 int set = extractSet(addr); 258 259 // prefer to evict an invalid block 260 for (int i = 0; i < allocAssoc; ++i) { 261 blk = sets[set].blks[i]; 262 if (!blk->isValid()) 263 break; 264 } 265 266 return blk; 267 } 268 269 /** 270 * Insert the new block into the cache. 271 * @param pkt Packet holding the address to update 272 * @param blk The block to update. 273 */ 274 void insertBlock(PacketPtr pkt, CacheBlk *blk) 275 { 276 Addr addr = pkt->getAddr(); 277 MasterID master_id = pkt->req->masterId(); 278 uint32_t task_id = pkt->req->taskId(); 279 280 if (!blk->isTouched) { 281 tagsInUse++; 282 blk->isTouched = true; 283 if (!warmedUp && tagsInUse.value() >= warmupBound) { 284 warmedUp = true; 285 warmupCycle = curTick(); 286 } 287 } 288 289 // If we're replacing a block that was previously valid update 290 // stats for it. This can't be done in findBlock() because a 291 // found block might not actually be replaced there if the 292 // coherence protocol says it can't be. 293 if (blk->isValid()) { 294 replacements[0]++; 295 totalRefs += blk->refCount; 296 ++sampledRefs; 297 blk->refCount = 0; 298 299 // deal with evicted block 300 assert(blk->srcMasterId < cache->system->maxMasters()); 301 occupancies[blk->srcMasterId]--; 302 303 blk->invalidate(); 304 } 305 306 blk->isTouched = true; 307 308 // Set tag for new block. Caller is responsible for setting status. 309 blk->tag = extractTag(addr); 310 311 // deal with what we are bringing in 312 assert(master_id < cache->system->maxMasters()); 313 occupancies[master_id]++; 314 blk->srcMasterId = master_id; 315 blk->task_id = task_id; 316 blk->tickInserted = curTick(); 317 318 // We only need to write into one tag and one data block. 319 tagAccesses += 1; 320 dataAccesses += 1; 321 } 322 323 /** 324 * Limit the allocation for the cache ways. 325 * @param ways The maximum number of ways available for replacement. 326 */ 327 virtual void setWayAllocationMax(int ways) 328 { 329 fatal_if(ways < 1, "Allocation limit must be greater than zero"); 330 allocAssoc = ways; 331 } 332 333 /** 334 * Get the way allocation mask limit. 335 * @return The maximum number of ways available for replacement. 336 */ 337 virtual int getWayAllocationMax() const 338 { 339 return allocAssoc; 340 } 341 342 /** 343 * Generate the tag from the given address. 344 * @param addr The address to get the tag from. 345 * @return The tag of the address. 346 */ 347 Addr extractTag(Addr addr) const 348 { 349 return (addr >> tagShift); 350 } 351 352 /** 353 * Calculate the set index from the address. 354 * @param addr The address to get the set from. 355 * @return The set index of the address. 356 */ 357 int extractSet(Addr addr) const 358 { 359 return ((addr >> setShift) & setMask); 360 } 361 362 /** 363 * Align an address to the block size. 364 * @param addr the address to align. 365 * @return The block address. 366 */ 367 Addr blkAlign(Addr addr) const 368 { 369 return (addr & ~(Addr)blkMask); 370 } 371 372 /** 373 * Regenerate the block address from the tag. 374 * @param tag The tag of the block. 375 * @param set The set of the block. 376 * @return The block address. 377 */ 378 Addr regenerateBlkAddr(Addr tag, unsigned set) const 379 { 380 return ((tag << tagShift) | ((Addr)set << setShift)); 381 } 382 383 /** 384 *iterated through all blocks and clear all locks 385 *Needed to clear all lock tracking at once 386 */ 387 virtual void clearLocks(); 388 389 /** 390 * Called at end of simulation to complete average block reference stats. 391 */ 392 virtual void cleanupRefs(); 393 394 /** 395 * Print all tags used 396 */ 397 virtual std::string print() const; 398 399 /** 400 * Called prior to dumping stats to compute task occupancy 401 */ 402 virtual void computeStats(); 403 404 /** 405 * Visit each block in the tag store and apply a visitor to the 406 * block. 407 * 408 * The visitor should be a function (or object that behaves like a 409 * function) that takes a cache block reference as its parameter 410 * and returns a bool. A visitor can request the traversal to be 411 * stopped by returning false, returning true causes it to be 412 * called for the next block in the tag store. 413 * 414 * \param visitor Visitor to call on each block. 415 */ 416 void forEachBlk(CacheBlkVisitor &visitor) M5_ATTR_OVERRIDE { 417 for (unsigned i = 0; i < numSets * assoc; ++i) { 418 if (!visitor(blks[i])) 419 return; 420 } 421 } 422}; 423 424#endif // __MEM_CACHE_TAGS_BASESETASSOC_HH__ 425