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