From c2d03ba24f52aec96bf569309a59022e0d4e3c21 Mon Sep 17 00:00:00 2001 From: "Daniel R. Carvalho" Date: Fri, 9 Mar 2018 16:44:23 +0100 Subject: [PATCH] mem-cache: Create LFU replacement policy Implementation of a Least Frequently Used replacement policy. Change-Id: I772afccd3a7955777e53d59341e922718db44e5c Reviewed-on: https://gem5-review.googlesource.com/8890 Reviewed-by: Nikos Nikoleris Maintainer: Nikos Nikoleris --- .../ReplacementPolicies.py | 5 ++ src/mem/cache/replacement_policies/SConscript | 1 + src/mem/cache/replacement_policies/lfu_rp.cc | 69 ++++++++++++++++++ src/mem/cache/replacement_policies/lfu_rp.hh | 70 +++++++++++++++++++ 4 files changed, 145 insertions(+) create mode 100644 src/mem/cache/replacement_policies/lfu_rp.cc create mode 100644 src/mem/cache/replacement_policies/lfu_rp.hh diff --git a/src/mem/cache/replacement_policies/ReplacementPolicies.py b/src/mem/cache/replacement_policies/ReplacementPolicies.py index 5f7ecfc5c..0beb3e60f 100644 --- a/src/mem/cache/replacement_policies/ReplacementPolicies.py +++ b/src/mem/cache/replacement_policies/ReplacementPolicies.py @@ -40,6 +40,11 @@ class FIFORP(BaseReplacementPolicy): cxx_class = 'FIFORP' cxx_header = "mem/cache/replacement_policies/fifo_rp.hh" +class LFURP(BaseReplacementPolicy): + type = 'LFURP' + cxx_class = 'LFURP' + cxx_header = "mem/cache/replacement_policies/lfu_rp.hh" + class LRURP(BaseReplacementPolicy): type = 'LRURP' cxx_class = 'LRURP' diff --git a/src/mem/cache/replacement_policies/SConscript b/src/mem/cache/replacement_policies/SConscript index 4ac8fe8e6..26c450a79 100644 --- a/src/mem/cache/replacement_policies/SConscript +++ b/src/mem/cache/replacement_policies/SConscript @@ -35,6 +35,7 @@ SimObject('ReplacementPolicies.py') Source('base.cc') Source('brrip_rp.cc') Source('fifo_rp.cc') +Source('lfu_rp.cc') Source('lru_rp.cc') Source('mru_rp.cc') Source('random_rp.cc') diff --git a/src/mem/cache/replacement_policies/lfu_rp.cc b/src/mem/cache/replacement_policies/lfu_rp.cc new file mode 100644 index 000000000..90a5ee227 --- /dev/null +++ b/src/mem/cache/replacement_policies/lfu_rp.cc @@ -0,0 +1,69 @@ +/** + * 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/lfu_rp.hh" + +#include "debug/CacheRepl.hh" + +LFURP::LFURP(const Params *p) + : BaseReplacementPolicy(p) +{ +} + +CacheBlk* +LFURP::getVictim(const 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->refCount < blk->refCount) { + blk = candidate; + } + } + + DPRINTF(CacheRepl, "set %x, way %x: selecting blk for replacement\n", + blk->set, blk->way); + + return blk; +} + +LFURP* +LFURPParams::create() +{ + return new LFURP(this); +} diff --git a/src/mem/cache/replacement_policies/lfu_rp.hh b/src/mem/cache/replacement_policies/lfu_rp.hh new file mode 100644 index 000000000..affc849a2 --- /dev/null +++ b/src/mem/cache/replacement_policies/lfu_rp.hh @@ -0,0 +1,70 @@ +/** + * 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 Least Frequently Used replacement policy. + * The victim is chosen using the reference frequency. The least referenced + * block is always chosen to be evicted, regardless of the amount of times + * it has been touched, or how long has passed since its last touch. + */ + +#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_LFU_RP_HH__ +#define __MEM_CACHE_REPLACEMENT_POLICIES_LFU_RP_HH__ + +#include "mem/cache/replacement_policies/base.hh" +#include "params/LFURP.hh" + +class LFURP : public BaseReplacementPolicy +{ + public: + /** Convenience typedef. */ + typedef LFURPParams Params; + + /** + * Construct and initiliaze this replacement policy. + */ + LFURP(const Params *p); + + /** + * Destructor. + */ + ~LFURP() {} + + /** + * Find replacement victim using reference frequency. + * + * @param cands Replacement candidates, selected by indexing policy. + * @return Cache block to be replaced. + */ + CacheBlk* getVictim(const ReplacementCandidates& candidates) override; +}; + +#endif // __MEM_CACHE_REPLACEMENT_POLICIES_LFU_RP_HH__ -- 2.30.2