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/**
* Copyright (c) 2018-2020 Inria
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* 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;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "mem/cache/replacement_policies/mru_rp.hh"
#include <cassert>
#include <memory>
#include "params/MRURP.hh"
#include "sim/cur_tick.hh"
namespace gem5
{
GEM5_DEPRECATED_NAMESPACE(ReplacementPolicy, replacement_policy);
namespace replacement_policy
{
MRU::MRU(const Params &p)
: Base(p)
{
}
void
MRU::invalidate(const std::shared_ptr<ReplacementData>& replacement_data)
{
// Reset last touch timestamp
std::static_pointer_cast<MRUReplData>(
replacement_data)->lastTouchTick = Tick(0);
}
void
MRU::touch(const std::shared_ptr<ReplacementData>& replacement_data) const
{
// Update last touch timestamp
std::static_pointer_cast<MRUReplData>(
replacement_data)->lastTouchTick = curTick();
}
void
MRU::reset(const std::shared_ptr<ReplacementData>& replacement_data) const
{
// Set last touch timestamp
std::static_pointer_cast<MRUReplData>(
replacement_data)->lastTouchTick = curTick();
}
ReplaceableEntry*
MRU::getVictim(const ReplacementCandidates& candidates) const
{
// There must be at least one replacement candidate
assert(candidates.size() > 0);
// Visit all candidates to find victim
ReplaceableEntry* victim = candidates[0];
for (const auto& candidate : candidates) {
std::shared_ptr<MRUReplData> candidate_replacement_data =
std::static_pointer_cast<MRUReplData>(candidate->replacementData);
// Stop searching entry if a cache line that doesn't warm up is found.
if (candidate_replacement_data->lastTouchTick == 0) {
victim = candidate;
break;
} else if (candidate_replacement_data->lastTouchTick >
std::static_pointer_cast<MRUReplData>(
victim->replacementData)->lastTouchTick) {
victim = candidate;
}
}
return victim;
}
std::shared_ptr<ReplacementData>
MRU::instantiateEntry()
{
return std::shared_ptr<ReplacementData>(new MRUReplData());
}
} // namespace replacement_policy
} // namespace gem5