From: Daniel R. Carvalho Date: Fri, 9 Mar 2018 15:48:26 +0000 (+0100) Subject: mem-cache: Create MRU replacement policy X-Git-Tag: v19.0.0.0~2218 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=8f1a604ec3ba2c54bbceef8d3ac188aa59d3a78e;p=gem5.git mem-cache: Create MRU replacement policy Implementation of a Most Recently Used replacement policy. Change-Id: Id52cb247ca25d4523dcc53490d113695dac6a3f1 Reviewed-on: https://gem5-review.googlesource.com/8889 Reviewed-by: Jason Lowe-Power Reviewed-by: Nikos Nikoleris Maintainer: Nikos Nikoleris --- diff --git a/src/mem/cache/replacement_policies/ReplacementPolicies.py b/src/mem/cache/replacement_policies/ReplacementPolicies.py index 64743819b..1907c363e 100644 --- a/src/mem/cache/replacement_policies/ReplacementPolicies.py +++ b/src/mem/cache/replacement_policies/ReplacementPolicies.py @@ -40,6 +40,11 @@ class LRURP(BaseReplacementPolicy): cxx_class = 'LRURP' cxx_header = "mem/cache/replacement_policies/lru_rp.hh" +class MRURP(BaseReplacementPolicy): + type = 'MRURP' + cxx_class = 'MRURP' + cxx_header = "mem/cache/replacement_policies/mru_rp.hh" + class RandomRP(BaseReplacementPolicy): type = 'RandomRP' cxx_class = 'RandomRP' diff --git a/src/mem/cache/replacement_policies/SConscript b/src/mem/cache/replacement_policies/SConscript index c3c89923f..6f9911086 100644 --- a/src/mem/cache/replacement_policies/SConscript +++ b/src/mem/cache/replacement_policies/SConscript @@ -34,4 +34,5 @@ SimObject('ReplacementPolicies.py') Source('base.cc') Source('lru_rp.cc') +Source('mru_rp.cc') Source('random_rp.cc') diff --git a/src/mem/cache/replacement_policies/mru_rp.cc b/src/mem/cache/replacement_policies/mru_rp.cc new file mode 100644 index 000000000..0a89d4373 --- /dev/null +++ b/src/mem/cache/replacement_policies/mru_rp.cc @@ -0,0 +1,87 @@ +/** + * 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/mru_rp.hh" + +#include "debug/CacheRepl.hh" + +MRURP::MRURP(const Params *p) + : BaseReplacementPolicy(p) +{ +} + +void +MRURP::touch(CacheBlk *blk) +{ + BaseReplacementPolicy::touch(blk); + + // Update last touch timestamp + blk->lastTouchTick = curTick(); +} + +void +MRURP::reset(CacheBlk *blk) +{ + BaseReplacementPolicy::reset(blk); + + // Set last touch timestamp + blk->lastTouchTick = blk->tickInserted; +} + +CacheBlk* +MRURP::getVictim(ReplacementCandidates& candidates) +{ + // There must be at least one replacement candidate + assert(candidates.size() > 0); + + // Visit all candidates to find victim + CacheBlk* blk = candidates[0]; + for (const auto& candidate : candidates) { + // Stop iteration if found an invalid block + if (!candidate->isValid()) { + blk = candidate; + break; + // Update victim block if necessary + } else if (candidate->lastTouchTick > blk->lastTouchTick) { + blk = candidate; + } + } + + DPRINTF(CacheRepl, "set %x, way %x: selecting blk for replacement\n", + blk->set, blk->way); + + return blk; +} + +MRURP* +MRURPParams::create() +{ + return new MRURP(this); +} diff --git a/src/mem/cache/replacement_policies/mru_rp.hh b/src/mem/cache/replacement_policies/mru_rp.hh new file mode 100644 index 000000000..d9276e689 --- /dev/null +++ b/src/mem/cache/replacement_policies/mru_rp.hh @@ -0,0 +1,83 @@ +/** + * 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 + */ + +/** + * @file + * Declaration of a Most Recently Used replacement policy. + * The victim is chosen using the timestamp. The block that was accessed the + * last is the one chosen to be replaced. + */ + +#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_MRU_RP_HH__ +#define __MEM_CACHE_REPLACEMENT_POLICIES_MRU_RP_HH__ + +#include "mem/cache/replacement_policies/base.hh" +#include "params/MRURP.hh" + +class MRURP : public BaseReplacementPolicy +{ + public: + /** Convenience typedef. */ + typedef MRURPParams Params; + + /** + * Construct and initiliaze this replacement policy. + */ + MRURP(const Params *p); + + /** + * Destructor. + */ + ~MRURP() {} + + /** + * Touch a block to update its last touch tick. + * + * @param blk Cache block to be touched. + */ + void touch(CacheBlk *blk); + + /** + * Reset replacement data for a block. Used when a block is inserted. + * Sets its last touch tick as the current tick. + * + * @param blk Cache block to be reset. + */ + void reset(CacheBlk *blk); + + /** + * Find replacement victim using access timestamps. + * @param cands Replacement candidates, selected by indexing policy. + * @return Cache block to be replaced. + */ + CacheBlk* getVictim(ReplacementCandidates& candidates) override; +}; + +#endif // __MEM_CACHE_REPLACEMENT_POLICIES_MRU_RP_HH__