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/**
* Copyright (c) 2018 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.
*
* Authors: Daniel Carvalho
*/
#include "mem/cache/replacement_policies/random_rp.hh"
#include "base/random.hh"
#include "debug/CacheRepl.hh"
RandomRP::RandomRP(const Params *p)
: BaseReplacementPolicy(p)
{
}
CacheBlk*
RandomRP::getVictim(const ReplacementCandidates& candidates)
{
// There must be at least one replacement candidate
assert(candidates.size() > 0);
// Choose one candidate at random
CacheBlk* blk = candidates[random_mt.random<unsigned>(0,
candidates.size() - 1)];
// Visit all candidates to find an invalid entry
for (const auto& candidate : candidates) {
// Give priority to victimise invalid entries
if (!candidate->isValid()){
blk = candidate;
break;
}
}
// If no invalid blocks were found, choose one of the candidates randomly
DPRINTF(CacheRepl, "set %x, way %x: selecting blk for replacement\n",
blk->set, blk->way);
return blk;
}
RandomRP*
RandomRPParams::create()
{
return new RandomRP(this);
}
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