Implementation of a Most Recently Used replacement policy.
Change-Id: Id52cb247ca25d4523dcc53490d113695dac6a3f1
Reviewed-on: https://gem5-review.googlesource.com/8889
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
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'
Source('base.cc')
Source('lru_rp.cc')
+Source('mru_rp.cc')
Source('random_rp.cc')
--- /dev/null
+/**
+ * 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);
+}
--- /dev/null
+/**
+ * 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__