src/cpu/trace/opt_cpu.cc

   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: Erik Hallnor
  29  */
  30
  31 /**
  32  * @file
  33  * Definition of a memory trace CPU object for optimal caches. Uses a memory
  34  * trace to access a fully associative cache with optimal replacement.
  35  */
  36
  37 #include <algorithm> // For heap functions.
  38
  39 #include "cpu/trace/opt_cpu.hh"
  40 #include "cpu/trace/reader/mem_trace_reader.hh"
  41 #include "params/OptCPU.hh"
  42 #include "sim/sim_events.hh"
  43
  44 using namespace std;
  45
  46 OptCPU::OptCPU(const string &name,
  47                MemTraceReader *_trace,
  48                int block_size,
  49                int cache_size,
  50                int _assoc)
  51     : SimObject(name), tickEvent(this), trace(_trace),
  52       numBlks(cache_size/block_size), assoc(_assoc), numSets(numBlks/assoc),
  53       setMask(numSets - 1)
  54 {
  55     int log_block_size = 0;
  56     int tmp_block_size = block_size;
  57     while (tmp_block_size > 1) {
  58         ++log_block_size;
  59         tmp_block_size = tmp_block_size >> 1;
  60     }
  61     assert(1<<log_block_size == block_size);
  62     MemReqPtr req;
  63     trace->getNextReq(req);
  64     refInfo.resize(numSets);
  65     while (req) {
  66         RefInfo temp;
  67         temp.addr = req->paddr >> log_block_size;
  68         int set = temp.addr & setMask;
  69         refInfo[set].push_back(temp);
  70         trace->getNextReq(req);
  71     }
  72
  73     // Initialize top level of lookup table.
  74     lookupTable.resize(16);
  75
  76     // Annotate references with next ref time.
  77     for (int k = 0; k < numSets; ++k) {
  78         for (RefIndex i = refInfo[k].size() - 1; i >= 0; --i) {
  79             Addr addr = refInfo[k][i].addr;
  80             initTable(addr, InfiniteRef);
  81             refInfo[k][i].nextRefTime = lookupValue(addr);
  82             setValue(addr, i);
  83         }
  84     }
  85
  86     // Reset the lookup table
  87     for (int j = 0; j < 16; ++j) {
  88         if (lookupTable[j].size() == (1<<16)) {
  89             for (int k = 0; k < (1<<16); ++k) {
  90                 if (lookupTable[j][k].size() == (1<<16)) {
  91                     for (int l = 0; l < (1<<16); ++l) {
  92                         lookupTable[j][k][l] = -1;
  93                     }
  94                 }
  95             }
  96         }
  97     }
  98
  99     tickEvent.schedule(0);
 100
 101     hits = 0;
 102     misses = 0;
 103 }
 104
 105 void
 106 OptCPU::processSet(int set)
 107 {
 108     // Initialize cache
 109     int blks_in_cache = 0;
 110     RefIndex i = 0;
 111     cacheHeap.clear();
 112     cacheHeap.resize(assoc);
 113
 114     while (blks_in_cache < assoc) {
 115         RefIndex cache_index = lookupValue(refInfo[set][i].addr);
 116         if (cache_index == -1) {
 117             // First reference to this block
 118             misses++;
 119             cache_index = blks_in_cache++;
 120             setValue(refInfo[set][i].addr, cache_index);
 121         } else {
 122             hits++;
 123         }
 124         // update cache heap to most recent reference
 125         cacheHeap[cache_index] = i;
 126         if (++i >= refInfo[set].size()) {
 127             return;
 128         }
 129     }
 130     for (int start = assoc/2; start >= 0; --start) {
 131         heapify(set,start);
 132     }
 133     //verifyHeap(set,0);
 134
 135     for (; i < refInfo[set].size(); ++i) {
 136         RefIndex cache_index = lookupValue(refInfo[set][i].addr);
 137         if (cache_index == -1) {
 138             // miss
 139             misses++;
 140             // replace from cacheHeap[0]
 141             // mark replaced block as absent
 142             setValue(refInfo[set][cacheHeap[0]].addr, -1);
 143             setValue(refInfo[set][i].addr, 0);
 144             cacheHeap[0] = i;
 145             heapify(set, 0);
 146             // Make sure its in the cache
 147             assert(lookupValue(refInfo[set][i].addr) != -1);
 148         } else {
 149             // hit
 150             hits++;
 151             assert(refInfo[set][cacheHeap[cache_index]].addr ==
 152                    refInfo[set][i].addr);
 153             assert(refInfo[set][cacheHeap[cache_index]].nextRefTime == i);
 154             assert(heapLeft(cache_index) >= assoc);
 155
 156             cacheHeap[cache_index] = i;
 157             processRankIncrease(set, cache_index);
 158             assert(lookupValue(refInfo[set][i].addr) != -1);
 159         }
 160     }
 161 }
 162 void
 163 OptCPU::tick()
 164 {
 165     // Do opt simulation
 166
 167     int references = 0;
 168     for (int set = 0; set < numSets; ++set) {
 169         if (!refInfo[set].empty()) {
 170             processSet(set);
 171         }
 172         references += refInfo[set].size();
 173     }
 174     // exit;
 175     fprintf(stderr,"sys.cpu.misses %d #opt cache misses\n",misses);
 176     fprintf(stderr,"sys.cpu.hits %d #opt cache hits\n", hits);
 177     fprintf(stderr,"sys.cpu.accesses %d #opt cache acceses\n", references);
 178     exitSimLoop("end of memory trace reached");
 179 }
 180
 181 void
 182 OptCPU::initTable(Addr addr, RefIndex index)
 183 {
 184     int l1_index = (addr >> 32) & 0x0f;
 185     int l2_index = (addr >> 16) & 0xffff;
 186     assert(l1_index == addr >> 32);
 187     if (lookupTable[l1_index].size() != (1<<16)) {
 188         lookupTable[l1_index].resize(1<<16);
 189     }
 190     if (lookupTable[l1_index][l2_index].size() != (1<<16)) {
 191         lookupTable[l1_index][l2_index].resize(1<<16, index);
 192     }
 193 }
 194
 195 OptCPU::TickEvent::TickEvent(OptCPU *c)
 196     : Event(&mainEventQueue, CPU_Tick_Pri), cpu(c)
 197 {
 198 }
 199
 200 void
 201 OptCPU::TickEvent::process()
 202 {
 203     cpu->tick();
 204 }
 205
 206 const char *
 207 OptCPU::TickEvent::description()
 208 {
 209     return "OptCPU tick event";
 210 }
 211
 212
 213 OptCPU *
 214 OptCPUParams::create()
 215 {
 216     return new OptCPU(name, data_trace, block_size, size, assoc);
 217 }