src/mem/cache/tags/random_repl.cc

   1 /*
   2  * Copyright (c) 2014 The Regents of The University of Michigan
   3  * Copyright (c) 2016 ARM Limited
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are
   8  * met: redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer;
  10  * redistributions in binary form must reproduce the above copyright
  11  * notice, this list of conditions and the following disclaimer in the
  12  * documentation and/or other materials provided with the distribution;
  13  * neither the name of the copyright holders nor the names of its
  14  * contributors may be used to endorse or promote products derived from
  15  * this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  19  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  20  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  21  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  22  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  27  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  *
  29  * Authors: Anthony Gutierrez
  30  */
  31
  32 /**
  33  * @file
  34  * Definitions of a random replacement tag store.
  35  */
  36
  37 #include "mem/cache/tags/random_repl.hh"
  38
  39 #include "base/random.hh"
  40 #include "debug/CacheRepl.hh"
  41 #include "mem/cache/base.hh"
  42
  43 RandomRepl::RandomRepl(const Params *p)
  44     : BaseSetAssoc(p)
  45
  46 {
  47 }
  48
  49 CacheBlk*
  50 RandomRepl::accessBlock(Addr addr, bool is_secure, Cycles &lat)
  51 {
  52     return BaseSetAssoc::accessBlock(addr, is_secure, lat);
  53 }
  54
  55 CacheBlk*
  56 RandomRepl::findVictim(Addr addr)
  57 {
  58     CacheBlk *blk = BaseSetAssoc::findVictim(addr);
  59     unsigned set = extractSet(addr);
  60
  61     // if all blocks are valid, pick a replacement at random
  62     if (blk && blk->isValid()) {
  63         // find a random index within the bounds of the set
  64         int idx = random_mt.random<int>(0, assoc - 1);
  65         blk = sets[set].blks[idx];
  66         // Enforce allocation limit
  67         while (blk->way >= allocAssoc) {
  68             idx = (idx + 1) % assoc;
  69             blk = sets[set].blks[idx];
  70         }
  71
  72         assert(idx < assoc);
  73         assert(idx >= 0);
  74         assert(blk->way < allocAssoc);
  75
  76         DPRINTF(CacheRepl, "set %x: selecting blk %x for replacement\n",
  77                 blk->set, regenerateBlkAddr(blk->tag, blk->set));
  78     }
  79
  80     return blk;
  81 }
  82
  83 void
  84 RandomRepl::insertBlock(PacketPtr pkt, BlkType *blk)
  85 {
  86     BaseSetAssoc::insertBlock(pkt, blk);
  87 }
  88
  89 void
  90 RandomRepl::invalidate(CacheBlk *blk)
  91 {
  92     BaseSetAssoc::invalidate(blk);
  93 }
  94
  95 RandomRepl*
  96 RandomReplParams::create()
  97 {
  98     return new RandomRepl(this);
  99 }