xref: /gem5/src/mem/cache/tags/base.cc

/*
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 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
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 * modified or unmodified, in source code or in binary form.
 *
 * Copyright (c) 2003-2005 The Regents of The University of Michigan
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * Authors: Erik Hallnor
 *          Ron Dreslinski
 */

/**
 * @file
 * Definitions of BaseTags.
 */

#include "mem/cache/tags/base.hh"

#include "cpu/smt.hh" //maxThreadsPerCPU
#include "mem/cache/base.hh"
#include "sim/sim_exit.hh"

using namespace std;

BaseTags::BaseTags(const Params *p)
    : ClockedObject(p), blkSize(p->block_size), blkMask(blkSize - 1),
      size(p->size),
      lookupLatency(p->tag_latency),
      accessLatency(p->sequential_access ?
                    p->tag_latency + p->data_latency :
                    std::max(p->tag_latency, p->data_latency)),
      cache(nullptr),
      warmupBound((p->warmup_percentage/100.0) * (p->size / p->block_size)),
      warmedUp(false), numBlocks(p->size / p->block_size),
      dataBlks(new uint8_t[p->size]) // Allocate data storage in one big chunk
{
}

void
BaseTags::setCache(BaseCache *_cache)
{
    assert(!cache);
    cache = _cache;
}

void
BaseTags::insertBlock(PacketPtr pkt, CacheBlk *blk)
{
    // Get address
    Addr addr = pkt->getAddr();

    // Update warmup data
    if (!blk->isTouched) {
        if (!warmedUp && tagsInUse.value() >= warmupBound) {
            warmedUp = true;
            warmupCycle = curTick();
        }
    }

    // If we're replacing a block that was previously valid update
    // stats for it. This can't be done in findBlock() because a
    // found block might not actually be replaced there if the
    // coherence protocol says it can't be.
    if (blk->isValid()) {
        replacements[0]++;
        totalRefs += blk->refCount;
        ++sampledRefs;

        invalidate(blk);
        blk->invalidate();
    }

    // Previous block, if existed, has been removed, and now we have
    // to insert the new one
    tagsInUse++;

    // Set tag for new block.  Caller is responsible for setting status.
    blk->tag = extractTag(addr);

    // Deal with what we are bringing in
    MasterID master_id = pkt->req->masterId();
    assert(master_id < cache->system->maxMasters());
    occupancies[master_id]++;
    blk->srcMasterId = master_id;

    // Set task id
    blk->task_id = pkt->req->taskId();

    // We only need to write into one tag and one data block.
    tagAccesses += 1;
    dataAccesses += 1;
}

void
BaseTags::regStats()
{
    ClockedObject::regStats();

    using namespace Stats;

    replacements
        .init(maxThreadsPerCPU)
        .name(name() + ".replacements")
        .desc("number of replacements")
        .flags(total)
        ;

    tagsInUse
        .name(name() + ".tagsinuse")
        .desc("Cycle average of tags in use")
        ;

    totalRefs
        .name(name() + ".total_refs")
        .desc("Total number of references to valid blocks.")
        ;

    sampledRefs
        .name(name() + ".sampled_refs")
        .desc("Sample count of references to valid blocks.")
        ;

    avgRefs
        .name(name() + ".avg_refs")
        .desc("Average number of references to valid blocks.")
        ;

    avgRefs = totalRefs/sampledRefs;

    warmupCycle
        .name(name() + ".warmup_cycle")
        .desc("Cycle when the warmup percentage was hit.")
        ;

    occupancies
        .init(cache->system->maxMasters())
        .name(name() + ".occ_blocks")
        .desc("Average occupied blocks per requestor")
        .flags(nozero | nonan)
        ;
    for (int i = 0; i < cache->system->maxMasters(); i++) {
        occupancies.subname(i, cache->system->getMasterName(i));
    }

    avgOccs
        .name(name() + ".occ_percent")
        .desc("Average percentage of cache occupancy")
        .flags(nozero | total)
        ;
    for (int i = 0; i < cache->system->maxMasters(); i++) {
        avgOccs.subname(i, cache->system->getMasterName(i));
    }

    avgOccs = occupancies / Stats::constant(numBlocks);

    occupanciesTaskId
        .init(ContextSwitchTaskId::NumTaskId)
        .name(name() + ".occ_task_id_blocks")
        .desc("Occupied blocks per task id")
        .flags(nozero | nonan)
        ;

    ageTaskId
        .init(ContextSwitchTaskId::NumTaskId, 5)
        .name(name() + ".age_task_id_blocks")
        .desc("Occupied blocks per task id")
        .flags(nozero | nonan)
        ;

    percentOccsTaskId
        .name(name() + ".occ_task_id_percent")
        .desc("Percentage of cache occupancy per task id")
        .flags(nozero)
        ;

    percentOccsTaskId = occupanciesTaskId / Stats::constant(numBlocks);

    tagAccesses
        .name(name() + ".tag_accesses")
        .desc("Number of tag accesses")
        ;

    dataAccesses
        .name(name() + ".data_accesses")
        .desc("Number of data accesses")
        ;

    registerDumpCallback(new BaseTagsDumpCallback(this));
    registerExitCallback(new BaseTagsCallback(this));
}