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 <cstring>
  40 #include <list>
  41
  42 #include "mem/cache/cache_blk.hh" // base class
  43 #include "mem/cache/tags/split_blk.hh"
  44 #include "mem/packet.hh" // for inlined functions
  45 #include <assert.h>
  46 #include "mem/cache/tags/base_tags.hh"
  47 #include "base/hashmap.hh"
  48
  49 class BaseCache;
  50 class SplitLRU;
  51 class SplitLIFO;
  52
  53 /**
  54  * A  cache tag store.
  55  */
  56 class Split : public BaseTags
  57 {
  58   public:
  59     /** Typedef the block type used in this tag store. */
  60     typedef SplitBlk BlkType;
  61     /** Typedef for a list of pointers to the local block class. */
  62     typedef std::list<SplitBlk*> BlkList;
  63   protected:
  64     /** The number of sets in the cache. */
  65     const int numSets;
  66     /** The number of bytes in a block. */
  67     const int blkSize;
  68     /** Whether the 2nd partition (for the nic) is LIFO or not */
  69     const bool lifo;
  70     /** The hit latency. */
  71     const int hitLatency;
  72
  73     Addr blkMask;
  74
  75     /** Number of NIC requests that hit in the NIC partition */
  76     Stats::Scalar<> NR_NP_hits;
  77     /** Number of NIC requests that hit in the CPU partition */
  78     Stats::Scalar<> NR_CP_hits;
  79     /** Number of CPU requests that hit in the NIC partition */
  80     Stats::Scalar<> CR_NP_hits;
  81     /** Number of CPU requests that hit in the CPU partition */
  82     Stats::Scalar<> CR_CP_hits;
  83     /** The number of nic replacements (i.e. misses) */
  84     Stats::Scalar<> nic_repl;
  85     /** The number of cpu replacements (i.e. misses) */
  86     Stats::Scalar<> cpu_repl;
  87
  88     //For latency studies
  89     /** the number of NIC blks that were used before evicted */
  90     Stats::Scalar<> nicUsedWhenEvicted;
  91     /** the total latency of used NIC blocks in the cache */
  92     Stats::Scalar<> nicUsedTotLatency;
  93     /** the total number of used NIC blocks evicted */
  94     Stats::Scalar<> nicUsedTotEvicted;
  95     /** the average number of cycles a used NIC blk is in the cache */
  96     Stats::Formula nicUsedAvgLatency;
  97     /** the Distribution of used NIC blk eviction times */
  98     Stats::Distribution<> usedEvictDist;
  99
 100     /** the number of NIC blks that were unused before evicted */
 101     Stats::Scalar<> nicUnusedWhenEvicted;
 102     /** the total latency of unused NIC blks in the cache */
 103     Stats::Scalar<> nicUnusedTotLatency;
 104     /** the total number of unused NIC blocks evicted */
 105     Stats::Scalar<> nicUnusedTotEvicted;
 106     /** the average number of cycles an unused NIC blk is in the cache */
 107     Stats::Formula nicUnusedAvgLatency;
 108     /** the Distribution of unused NIC blk eviction times */
 109     Stats::Distribution<> unusedEvictDist;
 110
 111     /** The total latency of NIC blocks to 1st usage time by CPU */
 112     Stats::Scalar<> nicUseByCPUCycleTotal;
 113     /** The total number of NIC blocks used */
 114     Stats::Scalar<> nicBlksUsedByCPU;
 115     /** the average number of cycles before a NIC blk that is used gets used by CPU */
 116     Stats::Formula nicAvgUsageByCPULatency;
 117     /** the Distribution of cycles time before a NIC blk is used by CPU*/
 118     Stats::Distribution<> useByCPUCycleDist;
 119
 120     /** the number of CPU blks that were used before evicted */
 121     Stats::Scalar<> cpuUsedBlks;
 122     /** the number of CPU blks that were unused before evicted */
 123     Stats::Scalar<> cpuUnusedBlks;
 124
 125     /** the avg number of cycles before a NIC blk is evicted */
 126     Stats::Formula nicAvgLatency;
 127
 128     typedef m5::hash_map<Addr, int, m5::hash<Addr> > hash_t;
 129     typedef hash_t::const_iterator memIter;
 130     hash_t memHash;
 131
 132
 133   private:
 134     SplitLRU *lru;
 135     SplitLRU *lru_net;
 136     SplitLIFO *lifo_net;
 137
 138   public:
 139     /**
 140      * Construct and initialize this tag store.
 141      * @param _numSets The number of sets in the cache.
 142      * @param _blkSize The number of bytes in a block.
 143      * @param _assoc The associativity of the cache.
 144      * @param _hit_latency The latency in cycles for a hit.
 145      */
 146     Split(int _numSets, int _blkSize, int total_ways, int LRU1_assoc,
 147           bool _lifo, bool _two_queue, int _hit_latency);
 148
 149     /**
 150      * Destructor
 151      */
 152     virtual ~Split();
 153
 154     /**
 155      * Register the stats for this object
 156      * @param name The name to prepend to the stats name.
 157      */
 158     void regStats(const std::string &name);
 159
 160     /**
 161      * Return the block size.
 162      * @return the block size.
 163      */
 164     int getBlockSize()
 165     {
 166         return blkSize;
 167     }
 168
 169     /**
 170      * Return the subblock size. In the case of Split it is always the block
 171      * size.
 172      * @return The block size.
 173      */
 174     int getSubBlockSize()
 175     {
 176         return blkSize;
 177     }
 178
 179     /**
 180      * Search for the address in the cache.
 181      * @param asid The address space ID.
 182      * @param addr The address to find.
 183      * @return True if the address is in the cache.
 184      */
 185     bool probe(Addr addr) const;
 186
 187     /**
 188      * Invalidate the given block.
 189      * @param blk The block to invalidate.
 190      */
 191     void invalidateBlk(BlkType *blk);
 192
 193     /**
 194      * Finds the given address in the cache and update replacement data.
 195      * Returns the access latency as a side effect.
 196      * @param addr The address to find.
 197      * @param asid The address space ID.
 198      * @param lat The access latency.
 199      * @return Pointer to the cache block if found.
 200      */
 201     SplitBlk* findBlock(Addr addr, int &lat);
 202
 203     /**
 204      * Finds the given address in the cache, do not update replacement data.
 205      * @param addr The address to find.
 206      * @param asid The address space ID.
 207      * @return Pointer to the cache block if found.
 208      */
 209     SplitBlk* findBlock(Addr addr) const;
 210
 211     /**
 212      * Find a replacement block for the address provided.
 213      * @param pkt The request to a find a replacement candidate for.
 214      * @param writebacks List for any writebacks to be performed.
 215      * @param compress_blocks List of blocks to compress, for adaptive comp.
 216      * @return The block to place the replacement in.
 217      */
 218     SplitBlk* findReplacement(PacketPtr &pkt, PacketList &writebacks,
 219                             BlkList &compress_blocks);
 220
 221
 222     /**
 223      * Generate the tag from the given address.
 224      * @param addr The address to get the tag from.
 225      * @param blk The block to find the partition it's in
 226      * @return The tag of the address.
 227      */
 228     Addr extractTag(Addr addr, SplitBlk *blk) const;
 229
 230     /**
 231      * Calculate the set index from the address.
 232      * @param addr The address to get the set from.
 233      * @return The set index of the address.
 234      */
 235     int extractSet(Addr addr) const
 236     {
 237         panic("should never call this!\n");
 238         M5_DUMMY_RETURN
 239     }
 240
 241     /**
 242      * Get the block offset from an address.
 243      * @param addr The address to get the offset of.
 244      * @return The block offset.
 245      */
 246     int extractBlkOffset(Addr addr) const
 247     {
 248         return (addr & blkMask);
 249     }
 250
 251     /**
 252      * Align an address to the block size.
 253      * @param addr the address to align.
 254      * @return The block address.
 255      */
 256     Addr blkAlign(Addr addr) const
 257     {
 258         return (addr & ~(Addr) (blkMask));
 259     }
 260
 261     /**
 262      * Regenerate the block address from the tag.
 263      * @param tag The tag of the block.
 264      * @param set The set of the block.
 265      * @return The block address.
 266      */
 267     Addr regenerateBlkAddr(Addr tag, int set) const;
 268
 269     /**
 270      * Return the hit latency.
 271      * @return the hit latency.
 272      */
 273     int getHitLatency() const
 274     {
 275         return hitLatency;
 276     }
 277
 278     /**
 279      * Read the data out of the internal storage of the given cache block.
 280      * @param blk The cache block to read.
 281      * @param data The buffer to read the data into.
 282      * @return The cache block's data.
 283      */
 284     void readData(SplitBlk *blk, uint8_t *data)
 285     {
 286         std::memcpy(data, blk->data, blk->size);
 287     }
 288
 289     /**
 290      * Write data into the internal storage of the given cache block. Since in
 291      * Split does not store data differently this just needs to update the size.
 292      * @param blk The cache block to write.
 293      * @param data The data to write.
 294      * @param size The number of bytes to write.
 295      * @param writebacks A list for any writebacks to be performed. May be
 296      * needed when writing to a compressed block.
 297      */
 298     void writeData(SplitBlk *blk, uint8_t *data, int size,
 299                    PacketList & writebacks)
 300     {
 301         assert(size <= blkSize);
 302         blk->size = size;
 303     }
 304
 305     /**
 306      * Called at end of simulation to complete average block reference stats.
 307      */
 308     virtual void cleanupRefs();
 309 };
 310
 311 #endif