random_rp.cc revision 12684:44ebd2bc020f
1/** 2 * Copyright (c) 2018 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 * Authors: Daniel Carvalho 29 */ 30 31#include "mem/cache/replacement_policies/random_rp.hh" 32 33#include "base/random.hh" 34#include "mem/cache/blk.hh" 35 36RandomRP::RandomRP(const Params *p) 37 : BaseReplacementPolicy(p) 38{ 39} 40 41void 42RandomRP::invalidate(const std::shared_ptr<ReplacementData>& replacement_data) 43const 44{ 45 // Unprioritize replacement data victimization 46 std::static_pointer_cast<RandomReplData>( 47 replacement_data)->valid = false; 48} 49 50void 51RandomRP::touch(const std::shared_ptr<ReplacementData>& replacement_data) const 52{ 53} 54 55void 56RandomRP::reset(const std::shared_ptr<ReplacementData>& replacement_data) const 57{ 58 // Unprioritize replacement data victimization 59 std::static_pointer_cast<RandomReplData>( 60 replacement_data)->valid = true; 61} 62 63ReplaceableEntry* 64RandomRP::getVictim(const ReplacementCandidates& candidates) const 65{ 66 // There must be at least one replacement candidate 67 assert(candidates.size() > 0); 68 69 // Choose one candidate at random 70 ReplaceableEntry* victim = candidates[random_mt.random<unsigned>(0, 71 candidates.size() - 1)]; 72 73 // Visit all candidates to search for an invalid entry. If one is found, 74 // its eviction is prioritized 75 for (const auto& candidate : candidates) { 76 if (!std::static_pointer_cast<RandomReplData>( 77 candidate->replacementData)->valid) { 78 victim = candidate; 79 break; 80 } 81 } 82 83 return victim; 84} 85 86std::shared_ptr<ReplacementData> 87RandomRP::instantiateEntry() 88{ 89 return std::shared_ptr<ReplacementData>(new ReplacementData()); 90} 91 92RandomRP* 93RandomRPParams::create() 94{ 95 return new RandomRP(this); 96} 97