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author | Anthony Gutierrez <atgutier@umich.edu> | 2014-07-28 12:23:23 -0400 |
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committer | Anthony Gutierrez <atgutier@umich.edu> | 2014-07-28 12:23:23 -0400 |
commit | a628afedade8d7b7cab108a81e714fc2755b4af3 (patch) | |
tree | 82ed5c90e74e3e3e0038e418c1281517ea55f62e /src/mem/cache/tags/random_repl.cc | |
parent | 0ac462459522771c7836f5f53e82c6a679c256ca (diff) | |
download | gem5-a628afedade8d7b7cab108a81e714fc2755b4af3.tar.xz |
mem: refactor LRU cache tags and add random replacement tags
this patch implements a new tags class that uses a random replacement policy.
these tags prefer to evict invalid blocks first, if none are available a
replacement candidate is chosen at random.
this patch factors out the common code in the LRU class and creates a new
abstract class: the BaseSetAssoc class. any set associative tag class must
implement the functionality related to the actual replacement policy in the
following methods:
accessBlock()
findVictim()
insertBlock()
invalidate()
Diffstat (limited to 'src/mem/cache/tags/random_repl.cc')
-rw-r--r-- | src/mem/cache/tags/random_repl.cc | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/src/mem/cache/tags/random_repl.cc b/src/mem/cache/tags/random_repl.cc new file mode 100644 index 000000000..77b379135 --- /dev/null +++ b/src/mem/cache/tags/random_repl.cc @@ -0,0 +1,89 @@ +/* + * Copyright (c) 2014 The Regents of The University of Michigan + * 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: Anthony Gutierrez + */ + +/** + * @file + * Definitions of a random replacement tag store. + */ + +#include "base/random.hh" +#include "debug/CacheRepl.hh" +#include "mem/cache/tags/random_repl.hh" +#include "mem/cache/base.hh" + +RandomRepl::RandomRepl(const Params *p) + : BaseSetAssoc(p) + +{ +} + +BaseSetAssoc::BlkType* +RandomRepl::accessBlock(Addr addr, bool is_secure, Cycles &lat, int master_id) +{ + return BaseSetAssoc::accessBlock(addr, is_secure, lat, master_id); +} + +BaseSetAssoc::BlkType* +RandomRepl::findVictim(Addr addr) const +{ + BlkType *blk = BaseSetAssoc::findVictim(addr); + + // if all blocks are valid, pick a replacement at random + if (blk->isValid()) { + // find a random index within the bounds of the set + int idx = random_mt.random<int>(0, assoc - 1); + assert(idx < assoc); + assert(idx >= 0); + blk = sets[extractSet(addr)].blks[idx]; + + DPRINTF(CacheRepl, "set %x: selecting blk %x for replacement\n", + blk->set, regenerateBlkAddr(blk->tag, blk->set)); + } + + return blk; +} + +void +RandomRepl::insertBlock(PacketPtr pkt, BlkType *blk) +{ + BaseSetAssoc::insertBlock(pkt, blk); +} + +void +RandomRepl::invalidate(BlkType *blk) +{ + BaseSetAssoc::invalidate(blk); +} + +RandomRepl* +RandomReplParams::create() +{ + return new RandomRepl(this); +} |