src/mem/cache/replacement_policies/bip_rp.cc

   1 /**
   2  * Copyright (c) 2018-2020 Inria
   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
  29 #include "mem/cache/replacement_policies/bip_rp.hh"
  30
  31 #include <memory>
  32
  33 #include "base/random.hh"
  34 #include "params/BIPRP.hh"
  35 #include "sim/core.hh"
  36
  37 namespace ReplacementPolicy {
  38
  39 BIP::BIP(const Params &p)
  40   : LRU(p), btp(p.btp)
  41 {
  42 }
  43
  44 void
  45 BIP::reset(const std::shared_ptr<ReplacementData>& replacement_data) const
  46 {
  47     std::shared_ptr<LRUReplData> casted_replacement_data =
  48         std::static_pointer_cast<LRUReplData>(replacement_data);
  49
  50     // Entries are inserted as MRU if lower than btp, LRU otherwise
  51     if (random_mt.random<unsigned>(1, 100) <= btp) {
  52         casted_replacement_data->lastTouchTick = curTick();
  53     } else {
  54         // Make their timestamps as old as possible, so that they become LRU
  55         casted_replacement_data->lastTouchTick = 1;
  56     }
  57 }
  58
  59 } // namespace ReplacementPolicy