cpu/trace/opt_cpu.hh

   1 /*
   2  * Copyright (c) 2004 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
  29 /**
  30  * @file
  31  * Declaration of a memory trace CPU object for optimal caches. Uses a memory
  32  * trace to access a fully associative cache with optimal replacement.
  33  */
  34
  35 #ifndef __OPT_CPU_HH__
  36 #define __OPT_CPU_HH__
  37
  38 #include <vector>
  39
  40 #include "cpu/base_cpu.hh"
  41 #include "mem/mem_req.hh" // for MemReqPtr
  42 #include "sim/eventq.hh" // for Event
  43
  44 // Forward Declaration
  45 class MemTraceReader;
  46
  47 /**
  48  * A CPU object to simulate a fully-associative cache with optimal replacement.
  49  */
  50 class OptCPU : public BaseCPU
  51 {
  52     typedef int RefIndex;
  53
  54     typedef std::vector<RefIndex> L3Table;
  55     typedef std::vector<L3Table> L2Table;
  56     typedef std::vector<L2Table> L1Table;
  57
  58     /**
  59      * Event to call OptCPU::tick
  60      */
  61     class TickEvent : public Event
  62     {
  63       private:
  64         /** The associated CPU */
  65         OptCPU *cpu;
  66
  67       public:
  68         /**
  69          * Construct this event;
  70          */
  71         TickEvent(OptCPU *c);
  72
  73         /**
  74          * Call the tick function.
  75          */
  76         void process();
  77
  78         /**
  79          * Return a string description of this event.
  80          */
  81         const char *description();
  82     };
  83
  84     TickEvent tickEvent;
  85
  86     class RefInfo
  87     {
  88       public:
  89         RefIndex nextRefTime;
  90         Addr addr;
  91     };
  92
  93     /** Reference Information, per set. */
  94     std::vector<std::vector<RefInfo> > refInfo;
  95
  96     /** Lookup table to track blocks in the cache heap */
  97     L1Table lookupTable;
  98
  99     /**
 100      * Return the correct value in the lookup table.
 101      */
 102     RefIndex lookupValue(Addr addr)
 103     {
 104         int l1_index = (addr >> 32) & 0x0f;
 105         int l2_index = (addr >> 16) & 0xffff;
 106         int l3_index = addr & 0xffff;
 107         assert(l1_index == addr >> 32);
 108         return lookupTable[l1_index][l2_index][l3_index];
 109     }
 110
 111     /**
 112      * Set the value in the lookup table.
 113      */
 114     void setValue(Addr addr, RefIndex index)
 115     {
 116         int l1_index = (addr >> 32) & 0x0f;
 117         int l2_index = (addr >> 16) & 0xffff;
 118         int l3_index = addr & 0xffff;
 119         assert(l1_index == addr >> 32);
 120         lookupTable[l1_index][l2_index][l3_index]=index;
 121     }
 122
 123     /**
 124      * Initialize the lookup table to the given value.
 125      */
 126     void initTable(Addr addr, RefIndex index);
 127
 128     void heapSwap(int set, int a, int b) {
 129         RefIndex tmp = cacheHeap[a];
 130         cacheHeap[a] = cacheHeap[b];
 131         cacheHeap[b] = tmp;
 132
 133         setValue(refInfo[set][cacheHeap[a]].addr, a);
 134         setValue(refInfo[set][cacheHeap[b]].addr, b);
 135     }
 136
 137     int heapLeft(int index) { return index + index + 1; }
 138     int heapRight(int index) { return index + index + 2; }
 139     int heapParent(int index) { return (index - 1) >> 1; }
 140
 141     RefIndex heapRank(int set, int index) {
 142         return refInfo[set][cacheHeap[index]].nextRefTime;
 143     }
 144
 145     void heapify(int set, int start){
 146         int left = heapLeft(start);
 147         int right = heapRight(start);
 148         int max = start;
 149         if (left < assoc && heapRank(set, left) > heapRank(set, start)) {
 150             max = left;
 151         }
 152         if (right < assoc && heapRank(set, right) >  heapRank(set, max)) {
 153             max = right;
 154         }
 155
 156         if (max != start) {
 157             heapSwap(set, start, max);
 158             heapify(set, max);
 159         }
 160     }
 161
 162     void verifyHeap(int set, int start) {
 163         int left = heapLeft(start);
 164         int right = heapRight(start);
 165
 166         if (left < assoc) {
 167             assert(heapRank(set, start) >= heapRank(set, left));
 168             verifyHeap(set, left);
 169         }
 170         if (right < assoc) {
 171             assert(heapRank(set, start) >= heapRank(set, right));
 172             verifyHeap(set, right);
 173         }
 174     }
 175
 176     void processRankIncrease(int set, int start) {
 177         int parent = heapParent(start);
 178         while (start > 0 && heapRank(set,parent) < heapRank(set,start)) {
 179             heapSwap(set, parent, start);
 180             start = parent;
 181             parent = heapParent(start);
 182         }
 183     }
 184
 185     void processSet(int set);
 186
 187     static const RefIndex InfiniteRef = 0x7fffffff;
 188
 189     /** Memory reference trace. */
 190     MemTraceReader *trace;
 191
 192     /** Cache heap for replacement. */
 193     std::vector<RefIndex> cacheHeap;
 194
 195     /** The number of blocks in the cache. */
 196     const int numBlks;
 197
 198     const int assoc;
 199     const int numSets;
 200     const int setMask;
 201
 202
 203     int misses;
 204     int hits;
 205
 206   public:
 207     /**
 208      * Construct a OptCPU object.
 209      */
 210     OptCPU(const std::string &name,
 211            MemTraceReader *_trace,
 212            int block_size,
 213            int cache_size,
 214            int assoc);
 215
 216     /**
 217      * Perform the optimal replacement simulation.
 218      */
 219     void tick();
 220 };
 221
 222 #endif