gem5/src/mem/cache/tags/base_set_assoc.cc

/*
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 * Copyright (c) 2003-2005,2014 The Regents of The University of Michigan
 * All rights reserved.
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 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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 * Authors: Erik Hallnor
 */

/**
 * @file
 * Definitions of a base set associative tag store.
 */

#include <string>

#include "base/intmath.hh"
#include "mem/cache/tags/base_set_assoc.hh"
#include "sim/core.hh"

using namespace std;

BaseSetAssoc::BaseSetAssoc(const Params *p)
    :BaseTags(p), assoc(p->assoc), allocAssoc(p->assoc),
     numSets(p->size / (p->block_size * p->assoc)),
     sequentialAccess(p->sequential_access)
{
    // Check parameters
    if (blkSize < 4 || !isPowerOf2(blkSize)) {
        fatal("Block size must be at least 4 and a power of 2");
    }
    if (numSets <= 0 || !isPowerOf2(numSets)) {
        fatal("# of sets must be non-zero and a power of 2");
    }
    if (assoc <= 0) {
        fatal("associativity must be greater than zero");
    }

    blkMask = blkSize - 1;
    setShift = floorLog2(blkSize);
    setMask = numSets - 1;
    tagShift = setShift + floorLog2(numSets);
    /** @todo Make warmup percentage a parameter. */
    warmupBound = numSets * assoc;

    sets = new SetType[numSets];
    blks = new BlkType[numSets * assoc];
    // allocate data storage in one big chunk
    numBlocks = numSets * assoc;
    dataBlks = new uint8_t[numBlocks * blkSize];

    unsigned blkIndex = 0;       // index into blks array
    for (unsigned i = 0; i < numSets; ++i) {
        sets[i].assoc = assoc;

        sets[i].blks = new BlkType*[assoc];

        // link in the data blocks
        for (unsigned j = 0; j < assoc; ++j) {
            // locate next cache block
            BlkType *blk = &blks[blkIndex];
            blk->data = &dataBlks[blkSize*blkIndex];
            ++blkIndex;

            // invalidate new cache block
            blk->invalidate();

            //EGH Fix Me : do we need to initialize blk?

            // Setting the tag to j is just to prevent long chains in the hash
            // table; won't matter because the block is invalid
            blk->tag = j;
            blk->whenReady = 0;
            blk->isTouched = false;
            blk->size = blkSize;
            sets[i].blks[j]=blk;
            blk->set = i;
            blk->way = j;
        }
    }
}

BaseSetAssoc::~BaseSetAssoc()
{
    delete [] dataBlks;
    delete [] blks;
    delete [] sets;
}

CacheBlk*
BaseSetAssoc::findBlock(Addr addr, bool is_secure) const
{
    Addr tag = extractTag(addr);
    unsigned set = extractSet(addr);
    BlkType *blk = sets[set].findBlk(tag, is_secure);
    return blk;
}

CacheBlk*
BaseSetAssoc::findBlockBySetAndWay(int set, int way) const
{
    return sets[set].blks[way];
}

void
BaseSetAssoc::clearLocks()
{
    for (int i = 0; i < numBlocks; i++){
        blks[i].clearLoadLocks();
    }
}

std::string
BaseSetAssoc::print() const {
    std::string cache_state;
    for (unsigned i = 0; i < numSets; ++i) {
        // link in the data blocks
        for (unsigned j = 0; j < assoc; ++j) {
            BlkType *blk = sets[i].blks[j];
            if (blk->isValid())
                cache_state += csprintf("\tset: %d block: %d %s\n", i, j,
                        blk->print());
        }
    }
    if (cache_state.empty())
        cache_state = "no valid tags\n";
    return cache_state;
}

void
BaseSetAssoc::cleanupRefs()
{
    for (unsigned i = 0; i < numSets*assoc; ++i) {
        if (blks[i].isValid()) {
            totalRefs += blks[i].refCount;
            ++sampledRefs;
        }
    }
}

void
BaseSetAssoc::computeStats()
{
    for (unsigned i = 0; i < ContextSwitchTaskId::NumTaskId; ++i) {
        occupanciesTaskId[i] = 0;
        for (unsigned j = 0; j < 5; ++j) {
            ageTaskId[i][j] = 0;
        }
    }

    for (unsigned i = 0; i < numSets * assoc; ++i) {
        if (blks[i].isValid()) {
            assert(blks[i].task_id < ContextSwitchTaskId::NumTaskId);
            occupanciesTaskId[blks[i].task_id]++;
            assert(blks[i].tickInserted <= curTick());
            Tick age = curTick() - blks[i].tickInserted;

            int age_index;
            if (age / SimClock::Int::us < 10) { // <10us
                age_index = 0;
            } else if (age / SimClock::Int::us < 100) { // <100us
                age_index = 1;
            } else if (age / SimClock::Int::ms < 1) { // <1ms
                age_index = 2;
            } else if (age / SimClock::Int::ms < 10) { // <10ms
                age_index = 3;
            } else
                age_index = 4; // >10ms

            ageTaskId[blks[i].task_id][age_index]++;
        }
    }
}