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#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__ 32#define __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__ 33
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34#include "mem/cache/base.hh"
35#include "mem/cache/blk.hh"
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34#include <memory> 35 |
36#include "params/BaseReplacementPolicy.hh" 37#include "sim/sim_object.hh" 38 39/**
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40 * The replacement data needed by the replacement policy. 41 * Each replacement policy should have its own replacement data. 42 */ 43struct ReplacementData {}; 44 45/** 46 * A replaceable entry is used by any table-like structure that needs to 47 * implement replacement functionality. It provides the replacement data 48 * pointer instantiated and needed by the replacement policy used. 49 * @sa Replacement Policies 50 */ 51class ReplaceableEntry 52{ 53 public: 54 /** 55 * Replacement data associated to this entry. 56 * It is instantiated by the replacement policy. 57 */ 58 std::shared_ptr<ReplacementData> replacementData; 59}; 60 61/** |
62 * Replacement candidates as chosen by the indexing policy.
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41 *
42 * The base functions touch() and reset() must be called by all subclasses
43 * that override them.
44 *
45 * @todo
46 * Currently the replacement candidates are simply the cache blocks
47 * derived from the possible placement locations of an address, as
48 * defined by the getPossibleLocations() from BaseTags. In a future
49 * patch it should be an inheritable class to allow the replacement
50 * policies to be used with any table-like structure that needs to
51 * replace its entries.
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63 */
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53typedef std::vector<CacheBlk*> ReplacementCandidates;
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64typedef std::vector<ReplaceableEntry*> ReplacementCandidates; |
65 66/** 67 * A common base class of cache replacement policy objects. 68 */ 69class BaseReplacementPolicy : public SimObject 70{ 71 public: 72 /** 73 * Convenience typedef. 74 */ 75 typedef BaseReplacementPolicyParams Params; 76 77 /** 78 * Construct and initiliaze this replacement policy. 79 */
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69 BaseReplacementPolicy(const Params *p);
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80 BaseReplacementPolicy(const Params *p) : SimObject(p) {} |
81 82 /** 83 * Destructor. 84 */ 85 virtual ~BaseReplacementPolicy() {} 86 87 /**
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77 * Touch a block to update its replacement data.
78 * Updates number of references.
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88 * Invalidate replacement data to set it as the next probable victim. |
89 *
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80 * This base function must be called by all subclasses that override it.
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90 * @param replacement_data Replacement data to be invalidated. 91 */ 92 virtual void invalidate(const std::shared_ptr<ReplacementData>& 93 replacement_data) const = 0; 94 95 /** 96 * Update replacement data. |
97 *
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82 * @param blk Cache block to be touched.
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98 * @param replacement_data Replacement data to be touched. |
99 */
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84 virtual void touch(CacheBlk *blk);
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100 virtual void touch(const std::shared_ptr<ReplacementData>& 101 replacement_data) const = 0; |
102 103 /**
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87 * Reset replacement data for a block. Used when a block is inserted.
88 * Sets the insertion tick, and update number of references.
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104 * Reset replacement data. Used when it's holder is inserted/validated. |
105 *
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90 * This base function must be called by all subclasses that override it.
91 *
92 * @param blk Cache block to be reset.
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106 * @param replacement_data Replacement data to be reset. |
107 */
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94 virtual void reset(CacheBlk *blk);
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108 virtual void reset(const std::shared_ptr<ReplacementData>& 109 replacement_data) const = 0; |
110 111 /** 112 * Find replacement victim among candidates. 113 * 114 * @param candidates Replacement candidates, selected by indexing policy.
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100 * @return Cache block to be replaced.
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115 * @return Replacement entry to be replaced. |
116 */
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102 virtual CacheBlk* getVictim(const ReplacementCandidates& candidates) = 0;
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117 virtual ReplaceableEntry* getVictim( 118 const ReplacementCandidates& candidates) const = 0; 119 120 /** 121 * Instantiate a replacement data entry. 122 * 123 * @return A shared pointer to the new replacement data. 124 */ 125 virtual std::shared_ptr<ReplacementData> instantiateEntry() = 0; |
126}; 127 128#endif // __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__
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