Daniel Carvalho has uploaded this change for review. (
https://gem5-review.googlesource.com/8890
Change subject: mem-cache: Create LFU replacement policy
......................................................................
mem-cache: Create LFU replacement policy
Implementation of a Least Frequently Used replacement policy.
Change-Id: I772afccd3a7955777e53d59341e922718db44e5c
---
M src/mem/cache/replacement_policies/ReplacementPolicies.py
M src/mem/cache/replacement_policies/SConscript
A src/mem/cache/replacement_policies/lfu_rp.cc
A src/mem/cache/replacement_policies/lfu_rp.hh
4 files changed, 179 insertions(+), 0 deletions(-)
diff --git a/src/mem/cache/replacement_policies/ReplacementPolicies.py
b/src/mem/cache/replacement_policies/ReplacementPolicies.py
index 0faa524..8396375 100644
--- a/src/mem/cache/replacement_policies/ReplacementPolicies.py
+++ b/src/mem/cache/replacement_policies/ReplacementPolicies.py
@@ -35,6 +35,11 @@
abstract = True
cxx_header = "mem/cache/replacement_policies/base.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 c3c8992..ca881ec 100644
--- a/src/mem/cache/replacement_policies/SConscript
+++ b/src/mem/cache/replacement_policies/SConscript
@@ -33,5 +33,6 @@
SimObject('ReplacementPolicies.py')
Source('base.cc')
+Source('lfu_rp.cc')
Source('lru_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 0000000..d7859f2
--- /dev/null
+++ b/src/mem/cache/replacement_policies/lfu_rp.cc
@@ -0,0 +1,88 @@
+/**
+ * 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)
+{
+}
+
+void
+LFURP::touch(CacheBlk *blk)
+{
+ BaseReplacementPolicy::touch(blk);
+
+ // Increase reference counter
+ blk->refCount++;
+}
+
+void
+LFURP::reset(CacheBlk *blk)
+{
+ BaseReplacementPolicy::reset(blk);
+
+ // Reset reference counter
+ blk->refCount = 0;
+}
+
+CacheBlk*
+LFURP::getVictim(ReplacementCandidates cands)
+{
+ // There must be at least one replacement candidate
+ assert(cands.size() > 0);
+
+ // Visit all candidates to find victim
+ CacheBlk* blk = cands[0];
+ for (auto it = cands.begin(); it != cands.end(); ++it) {
+ // Stop iteration if found an invalid block
+ if (!(*it)->isValid()) {
+ blk = *it;
+ break;
+ // Update victim block if necessary
+ } else if (!(*it)->isValid() or
+ ((*it)->refCount < blk->refCount)) {
+ blk = *it;
+ }
+ }
+
+ 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 0000000..a4ef783
--- /dev/null
+++ b/src/mem/cache/replacement_policies/lfu_rp.hh
@@ -0,0 +1,85 @@
+/**
+ * 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() {}
+
+ /**
+ * Touch a block to update its reference counter.
+ *
+ * @param blk Cache block to be touched.
+ */
+ void touch(CacheBlk *blk);
+
+ /**
+ * Reset replacement data for a block. Used when a block is inserted.
+ * Reset reference counter.
+ *
+ * @param blk Cache block to be reset.
+ */
+ void reset(CacheBlk *blk);
+
+ /**
+ * Find replacement victim using reference frequency.
+ *
+ * @param cands Replacement candidates, selected by indexing policy.
+ * @return Cache block to be replaced.
+ */
+ CacheBlk* getVictim(ReplacementCandidates cands) override;
+};
+
+#endif // __MEM_CACHE_REPLACEMENT_POLICIES_LFU_RP_HH__
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I772afccd3a7955777e53d59341e922718db44e5c
Gerrit-Change-Number: 8890
Gerrit-PatchSet: 1
Gerrit-Owner: Daniel Carvalho <oda...@yahoo.com.br>
Gerrit-MessageType: newchange
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