src/mem/cache/tags/split.hh

   1 /*
   2  * Copyright (c) 2004-2005 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: Lisa Hsu
  29  */
  30
  31 /**
  32  * @file
  33  * Declaration of a split/partitioned tag store.
  34  */
  35
  36 #ifndef __SPLIT_HH__
  37 #define __SPLIT_HH__
  38
  39 #include <list>
  40
  41 #include "mem/cache/cache_blk.hh" // base class
  42 #include "mem/cache/tags/split_blk.hh"
  43 #include "mem/packet.hh" // for inlined functions
  44 #include <assert.h>
  45 #include "mem/cache/tags/base_tags.hh"
  46 #include "base/hashmap.hh"
  47
  48 class BaseCache;
  49 class SplitLRU;
  50 class SplitLIFO;
  51
  52 /**
  53  * A  cache tag store.
  54  */
  55 class Split : public BaseTags
  56 {
  57   public:
  58     /** Typedef the block type used in this tag store. */
  59     typedef SplitBlk BlkType;
  60     /** Typedef for a list of pointers to the local block class. */
  61     typedef std::list<SplitBlk*> BlkList;
  62   protected:
  63     /** The number of sets in the cache. */
  64     const int numSets;
  65     /** The number of bytes in a block. */
  66     const int blkSize;
  67     /** Whether the 2nd partition (for the nic) is LIFO or not */
  68     const bool lifo;
  69     /** The hit latency. */
  70     const int hitLatency;
  71
  72     Addr blkMask;
  73
  74     /** Number of NIC requests that hit in the NIC partition */
  75     Stats::Scalar<> NR_NP_hits;
  76     /** Number of NIC requests that hit in the CPU partition */
  77     Stats::Scalar<> NR_CP_hits;
  78     /** Number of CPU requests that hit in the NIC partition */
  79     Stats::Scalar<> CR_NP_hits;
  80     /** Number of CPU requests that hit in the CPU partition */
  81     Stats::Scalar<> CR_CP_hits;
  82     /** The number of nic replacements (i.e. misses) */
  83     Stats::Scalar<> nic_repl;
  84     /** The number of cpu replacements (i.e. misses) */
  85     Stats::Scalar<> cpu_repl;
  86
  87     //For latency studies
  88     /** the number of NIC blks that were used before evicted */
  89     Stats::Scalar<> nicUsedWhenEvicted;
  90     /** the total latency of used NIC blocks in the cache */
  91     Stats::Scalar<> nicUsedTotLatency;
  92     /** the total number of used NIC blocks evicted */
  93     Stats::Scalar<> nicUsedTotEvicted;
  94     /** the average number of cycles a used NIC blk is in the cache */
  95     Stats::Formula nicUsedAvgLatency;
  96     /** the Distribution of used NIC blk eviction times */
  97     Stats::Distribution<> usedEvictDist;
  98
  99     /** the number of NIC blks that were unused before evicted */
 100     Stats::Scalar<> nicUnusedWhenEvicted;
 101     /** the total latency of unused NIC blks in the cache */
 102     Stats::Scalar<> nicUnusedTotLatency;
 103     /** the total number of unused NIC blocks evicted */
 104     Stats::Scalar<> nicUnusedTotEvicted;
 105     /** the average number of cycles an unused NIC blk is in the cache */
 106     Stats::Formula nicUnusedAvgLatency;
 107     /** the Distribution of unused NIC blk eviction times */
 108     Stats::Distribution<> unusedEvictDist;
 109
 110     /** The total latency of NIC blocks to 1st usage time by CPU */
 111     Stats::Scalar<> nicUseByCPUCycleTotal;
 112     /** The total number of NIC blocks used */
 113     Stats::Scalar<> nicBlksUsedByCPU;
 114     /** the average number of cycles before a NIC blk that is used gets used by CPU */
 115     Stats::Formula nicAvgUsageByCPULatency;
 116     /** the Distribution of cycles time before a NIC blk is used by CPU*/
 117     Stats::Distribution<> useByCPUCycleDist;
 118
 119     /** the number of CPU blks that were used before evicted */
 120     Stats::Scalar<> cpuUsedBlks;
 121     /** the number of CPU blks that were unused before evicted */
 122     Stats::Scalar<> cpuUnusedBlks;
 123
 124     /** the avg number of cycles before a NIC blk is evicted */
 125     Stats::Formula nicAvgLatency;
 126
 127     typedef m5::hash_map<Addr, int, m5::hash<Addr> > hash_t;
 128     typedef hash_t::const_iterator memIter;
 129     hash_t memHash;
 130
 131
 132   private:
 133     SplitLRU *lru;
 134     SplitLRU *lru_net;
 135     SplitLIFO *lifo_net;
 136
 137   public:
 138     /**
 139      * Construct and initialize this tag store.
 140      * @param _numSets The number of sets in the cache.
 141      * @param _blkSize The number of bytes in a block.
 142      * @param _assoc The associativity of the cache.
 143      * @param _hit_latency The latency in cycles for a hit.
 144      */
 145     Split(int _numSets, int _blkSize, int total_ways, int LRU1_assoc,
 146           bool _lifo, bool _two_queue, int _hit_latency);
 147
 148     /**
 149      * Destructor
 150      */
 151     virtual ~Split();
 152
 153     /**
 154      * Register the stats for this object
 155      * @param name The name to prepend to the stats name.
 156      */
 157     void regStats(const std::string &name);
 158
 159     /**
 160      * Return the block size.
 161      * @return the block size.
 162      */
 163     int getBlockSize()
 164     {
 165         return blkSize;
 166     }
 167
 168     /**
 169      * Return the subblock size. In the case of Split it is always the block
 170      * size.
 171      * @return The block size.
 172      */
 173     int getSubBlockSize()
 174     {
 175         return blkSize;
 176     }
 177
 178     /**
 179      * Search for the address in the cache.
 180      * @param asid The address space ID.
 181      * @param addr The address to find.
 182      * @return True if the address is in the cache.
 183      */
 184     bool probe(Addr addr) const;
 185
 186     /**
 187      * Invalidate the given block.
 188      * @param blk The block to invalidate.
 189      */
 190     void invalidateBlk(BlkType *blk);
 191
 192     /**
 193      * Finds the given address in the cache and update replacement data.
 194      * Returns the access latency as a side effect.
 195      * @param addr The address to find.
 196      * @param asid The address space ID.
 197      * @param lat The access latency.
 198      * @return Pointer to the cache block if found.
 199      */
 200     SplitBlk* findBlock(Addr addr, int &lat);
 201
 202     /**
 203      * Finds the given address in the cache, do not update replacement data.
 204      * @param addr The address to find.
 205      * @param asid The address space ID.
 206      * @return Pointer to the cache block if found.
 207      */
 208     SplitBlk* findBlock(Addr addr) const;
 209
 210     /**
 211      * Find a replacement block for the address provided.
 212      * @param pkt The request to a find a replacement candidate for.
 213      * @param writebacks List for any writebacks to be performed.
 214      * @param compress_blocks List of blocks to compress, for adaptive comp.
 215      * @return The block to place the replacement in.
 216      */
 217     SplitBlk* findReplacement(PacketPtr &pkt, PacketList &writebacks,
 218                             BlkList &compress_blocks);
 219
 220
 221     /**
 222      * Generate the tag from the given address.
 223      * @param addr The address to get the tag from.
 224      * @param blk The block to find the partition it's in
 225      * @return The tag of the address.
 226      */
 227     Addr extractTag(Addr addr, SplitBlk *blk) const;
 228
 229     /**
 230      * Calculate the set index from the address.
 231      * @param addr The address to get the set from.
 232      * @return The set index of the address.
 233      */
 234     int extractSet(Addr addr) const
 235     {
 236         panic("should never call this!\n");
 237     }
 238
 239     /**
 240      * Get the block offset from an address.
 241      * @param addr The address to get the offset of.
 242      * @return The block offset.
 243      */
 244     int extractBlkOffset(Addr addr) const
 245     {
 246         return (addr & blkMask);
 247     }
 248
 249     /**
 250      * Align an address to the block size.
 251      * @param addr the address to align.
 252      * @return The block address.
 253      */
 254     Addr blkAlign(Addr addr) const
 255     {
 256         return (addr & ~(Addr) (blkMask));
 257     }
 258
 259     /**
 260      * Regenerate the block address from the tag.
 261      * @param tag The tag of the block.
 262      * @param set The set of the block.
 263      * @return The block address.
 264      */
 265     Addr regenerateBlkAddr(Addr tag, int set) const;
 266
 267     /**
 268      * Return the hit latency.
 269      * @return the hit latency.
 270      */
 271     int getHitLatency() const
 272     {
 273         return hitLatency;
 274     }
 275
 276     /**
 277      * Read the data out of the internal storage of the given cache block.
 278      * @param blk The cache block to read.
 279      * @param data The buffer to read the data into.
 280      * @return The cache block's data.
 281      */
 282     void readData(SplitBlk *blk, uint8_t *data)
 283     {
 284         memcpy(data, blk->data, blk->size);
 285     }
 286
 287     /**
 288      * Write data into the internal storage of the given cache block. Since in
 289      * Split does not store data differently this just needs to update the size.
 290      * @param blk The cache block to write.
 291      * @param data The data to write.
 292      * @param size The number of bytes to write.
 293      * @param writebacks A list for any writebacks to be performed. May be
 294      * needed when writing to a compressed block.
 295      */
 296     void writeData(SplitBlk *blk, uint8_t *data, int size,
 297                    PacketList & writebacks)
 298     {
 299         assert(size <= blkSize);
 300         blk->size = size;
 301     }
 302
 303     /**
 304      * Called at end of simulation to complete average block reference stats.
 305      */
 306     virtual void cleanupRefs();
 307 };
 308
 309 #endif