src/mem/cache/tags/random_repl.cc

   1 /*
   2  * Copyright (c) 2014 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Anthony Gutierrez
  29  */
  30
  31 /**
  32  * @file
  33  * Definitions of a random replacement tag store.
  34  */
  35
  36 #include "mem/cache/tags/random_repl.hh"
  37
  38 #include "base/random.hh"
  39 #include "debug/CacheRepl.hh"
  40 #include "mem/cache/base.hh"
  41
  42 RandomRepl::RandomRepl(const Params *p)
  43     : BaseSetAssoc(p)
  44
  45 {
  46 }
  47
  48 CacheBlk*
  49 RandomRepl::accessBlock(Addr addr, bool is_secure, Cycles &lat, int master_id)
  50 {
  51     return BaseSetAssoc::accessBlock(addr, is_secure, lat, master_id);
  52 }
  53
  54 CacheBlk*
  55 RandomRepl::findVictim(Addr addr)
  56 {
  57     CacheBlk *blk = BaseSetAssoc::findVictim(addr);
  58     unsigned set = extractSet(addr);
  59
  60     // if all blocks are valid, pick a replacement at random
  61     if (blk && blk->isValid()) {
  62         // find a random index within the bounds of the set
  63         int idx = random_mt.random<int>(0, assoc - 1);
  64         blk = sets[set].blks[idx];
  65         // Enforce allocation limit
  66         while (blk->way >= allocAssoc) {
  67             idx = (idx + 1) % assoc;
  68             blk = sets[set].blks[idx];
  69         }
  70
  71         assert(idx < assoc);
  72         assert(idx >= 0);
  73         assert(blk->way < allocAssoc);
  74
  75         DPRINTF(CacheRepl, "set %x: selecting blk %x for replacement\n",
  76                 blk->set, regenerateBlkAddr(blk->tag, blk->set));
  77     }
  78
  79     return blk;
  80 }
  81
  82 void
  83 RandomRepl::insertBlock(PacketPtr pkt, BlkType *blk)
  84 {
  85     BaseSetAssoc::insertBlock(pkt, blk);
  86 }
  87
  88 void
  89 RandomRepl::invalidate(CacheBlk *blk)
  90 {
  91     BaseSetAssoc::invalidate(blk);
  92 }
  93
  94 RandomRepl*
  95 RandomReplParams::create()
  96 {
  97     return new RandomRepl(this);
  98 }