Daniel Carvalho has uploaded this change for review. (
https://gem5-review.googlesource.com/8891
Change subject: mem-cache: Create RRIP replacement policy
......................................................................
mem-cache: Create RRIP replacement policy
Implementation of a Re-Reference Interval Prediction replacement
policy.
Change-Id: I25d4a59a60ef7ac496c66852e394fd6cbaf50912
---
M src/mem/cache/blk.hh
M src/mem/cache/replacement_policies/ReplacementPolicies.py
M src/mem/cache/replacement_policies/SConscript
A src/mem/cache/replacement_policies/rrip_rp.cc
A src/mem/cache/replacement_policies/rrip_rp.hh
5 files changed, 237 insertions(+), 0 deletions(-)
diff --git a/src/mem/cache/blk.hh b/src/mem/cache/blk.hh
index a1e4502..65f32ff 100644
--- a/src/mem/cache/blk.hh
+++ b/src/mem/cache/blk.hh
@@ -129,6 +129,11 @@
*/
Tick lastTouchTick;
+ /**
+ * Re-Reference Interval Prediction Value. Used with RRIP repl policy.
+ */
+ unsigned rrpv;
+
protected:
/**
* Represents that the indicated thread context has a "lock" on
diff --git a/src/mem/cache/replacement_policies/ReplacementPolicies.py
b/src/mem/cache/replacement_policies/ReplacementPolicies.py
index 0faa524..5798ae8 100644
--- a/src/mem/cache/replacement_policies/ReplacementPolicies.py
+++ b/src/mem/cache/replacement_policies/ReplacementPolicies.py
@@ -44,3 +44,11 @@
type = 'RandomRP'
cxx_class = 'RandomRP'
cxx_header = "mem/cache/replacement_policies/random_rp.hh"
+
+class RRIPRP(BaseReplacementPolicy):
+ type = 'RRIPRP'
+ cxx_class = 'RRIPRP'
+ cxx_header = "mem/cache/replacement_policies/rrip_rp.hh"
+ max_RRPV = Param.Unsigned(3, "Maximum RRPV possible")
+ hit_priority = Param.Bool(False,
+ "Prioritize evicting blocks that havent had a hit recently")
diff --git a/src/mem/cache/replacement_policies/SConscript
b/src/mem/cache/replacement_policies/SConscript
index c3c8992..ebe5397 100644
--- a/src/mem/cache/replacement_policies/SConscript
+++ b/src/mem/cache/replacement_policies/SConscript
@@ -35,3 +35,4 @@
Source('base.cc')
Source('lru_rp.cc')
Source('random_rp.cc')
+Source('rrip_rp.cc')
diff --git a/src/mem/cache/replacement_policies/rrip_rp.cc
b/src/mem/cache/replacement_policies/rrip_rp.cc
new file mode 100644
index 0000000..9d7ae83
--- /dev/null
+++ b/src/mem/cache/replacement_policies/rrip_rp.cc
@@ -0,0 +1,105 @@
+/**
+ * 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/rrip_rp.hh"
+
+#include "debug/CacheRepl.hh"
+
+RRIPRP::RRIPRP(const Params *p)
+ : BaseReplacementPolicy(p),
+ maxRRPV(p->max_RRPV), hitPriority(p->hit_priority)
+{
+}
+
+void
+RRIPRP::touch(CacheBlk *blk)
+{
+ BaseReplacementPolicy::touch(blk);
+
+ // Update RRPV if not 0 yet
+ // Every hit in HP mode makes the block the last to be evicted, while
+ // in FP mode a hit makes the block less likely to be evicted
+ if (hitPriority)
+ blk->rrpv = 0;
+ else if (blk->rrpv)
+ blk->rrpv--;
+}
+
+void
+RRIPRP::reset(CacheBlk *blk)
+{
+ BaseReplacementPolicy::reset(blk);
+
+ // Reset RRPV
+ // Blocks are inserted as having a distant re-reference interval
+ blk->rrpv = maxRRPV;
+}
+
+CacheBlk*
+RRIPRP::getVictim(ReplacementCandidates cands)
+{
+ // There must be at least one replacement candidate
+ assert(cands.size() > 0);
+
+ // Use visitor to search for the 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)->rrpv > blk->rrpv)) {
+ blk = *it;
+ }
+ }
+
+ // Get difference of block's RRPV to the highest possible RRPV in
+ // order to update the RRPV of all the other blocks accordingly
+ uint32_t diff = maxRRPV - blk->rrpv;
+
+ // Update RRPV of all candidates
+ for (auto it = cands.begin(); it != cands.end(); ++it){
+ // Update the block's RPPV with the new value
+ (*it)->rrpv += diff;
+ }
+
+ DPRINTF(CacheRepl, "set %x, way %x: selecting blk for replacement\n",
+ blk->set, blk->way);
+
+ return blk;
+}
+
+RRIPRP*
+RRIPRPParams::create()
+{
+ return new RRIPRP(this);
+}
diff --git a/src/mem/cache/replacement_policies/rrip_rp.hh
b/src/mem/cache/replacement_policies/rrip_rp.hh
new file mode 100644
index 0000000..0fe67aa
--- /dev/null
+++ b/src/mem/cache/replacement_policies/rrip_rp.hh
@@ -0,0 +1,118 @@
+/**
+ * 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 Re-Reference Interval Prediction replacement policy.
+ * RRIP is an extension of NRU that uses a re-reference prediction value
+ * to determine if blocks are going to be re-used in the near future or
not.
+ *
+ * The higher the value of the RRPV, the more distant the block is from
+ * its next access.
+ */
+
+#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_RRIP_RP_HH__
+#define __MEM_CACHE_REPLACEMENT_POLICIES_RRIP_RP_HH__
+
+#include "mem/cache/replacement_policies/base.hh"
+#include "params/RRIPRP.hh"
+
+class RRIPRP : public BaseReplacementPolicy
+{
+ protected:
+ /**
+ * Maximum Re-Reference Prediction Value possible. A block with this
+ * value as the rrpv has the longest possible re-reference interval,
+ * that is, it is likely not to be used in the near future, and is
+ * among the best eviction candidates.
+ * A maxRRPV of 1 implies in a NRU.
+ */
+ unsigned maxRRPV;
+
+ /**
+ * The hit priority (HP) policy replaces blocks that do not receive
cache
+ * hits over any cache block that receives a hit, while the frequency
+ * priority (FP) policy replaces infrequently re-referenced blocks.
+ */
+ const bool hitPriority;
+
+ public:
+ /** Convenience typedef. */
+ typedef RRIPRPParams Params;
+
+ /**
+ * Construct and initiliaze this replacement policy.
+ */
+ RRIPRP(const Params *p);
+
+ /**
+ * Destructor.
+ */
+ ~RRIPRP() {}
+
+ /**
+ * Set maximum Re-Reference Prediction Value.
+ *
+ * @param maxRRPV New maximum RRPV.
+ */
+ void setMaxRRPV(unsigned maxRRPV){ this->maxRRPV = maxRRPV; }
+
+ /**
+ * Touch a block to update its replacement data.
+ *
+ * @param blk Cache block to be touched.
+ */
+ void touch(CacheBlk *blk) override;
+
+ /**
+ * Reset replacement data for a block. Used when a block is inserted.
+ * Sets the insertion tick, and update correspondent replacement data.
+ * Set RRPV according to the insertion policy used.
+ *
+ * @param blk Cache block to be reset.
+ */
+ void reset(CacheBlk *blk) override;
+
+ /**
+ * Find replacement victim using rrpv.
+ *
+ * @param cands Replacement candidates, selected by indexing policy.
+ * @return Cache block to be replaced.
+ */
+ CacheBlk* getVictim(ReplacementCandidates cands) override;
+};
+
+/**
+ * From the original paper, this implementation of RRIP is also called
+ * Static RRIP (SRRIP), as it always inserts blocks with the same RRPV.
+ */
+typedef RRIPRP SRRIPRP;
+
+#endif // __MEM_CACHE_REPLACEMENT_POLICIES_RRIP_RP_HH__
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I25d4a59a60ef7ac496c66852e394fd6cbaf50912
Gerrit-Change-Number: 8891
Gerrit-PatchSet: 1
Gerrit-Owner: Daniel Carvalho <oda...@yahoo.com.br>
Gerrit-MessageType: newchange
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