brrip_rp.hh (12626:e161d7725d4b) | brrip_rp.hh (12684:44ebd2bc020f) |
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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; --- 19 unchanged lines hidden (view full) --- 28 * Authors: Daniel Carvalho 29 */ 30 31/** 32 * @file 33 * Declaration of a Re-Reference Interval Prediction replacement policy. 34 * 35 * Not-Recently Used (NRU) is an approximation of LRU that uses a single bit | 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; --- 19 unchanged lines hidden (view full) --- 28 * Authors: Daniel Carvalho 29 */ 30 31/** 32 * @file 33 * Declaration of a Re-Reference Interval Prediction replacement policy. 34 * 35 * Not-Recently Used (NRU) is an approximation of LRU that uses a single bit |
36 * to determine if a block is going to be re-referenced in the near or distant | 36 * to determine if an entry is going to be re-referenced in the near or distant |
37 * future. 38 * 39 * Re-Reference Interval Prediction (RRIP) is an extension of NRU that uses a | 37 * future. 38 * 39 * Re-Reference Interval Prediction (RRIP) is an extension of NRU that uses a |
40 * re-reference prediction value to determine if blocks are going to be re- | 40 * re-reference prediction value to determine if entries are going to be re- |
41 * used in the near future or not. 42 * | 41 * used in the near future or not. 42 * |
43 * The higher the value of the RRPV, the more distant the block is from 44 * its next access. | 43 * The higher the value of the RRPV, the more distant the entry is from its 44 * next access. |
45 * 46 * Bimodal Re-Reference Interval Prediction (BRRIP) is an extension of RRIP | 45 * 46 * Bimodal Re-Reference Interval Prediction (BRRIP) is an extension of RRIP |
47 * that has a probability of not inserting blocks as the LRU. This probability | 47 * that has a probability of not inserting entries as the LRU. This probability |
48 * is controlled by the bimodal throtle parameter (btp). 49 * 50 * From the original paper, this implementation of RRIP is also called | 48 * is controlled by the bimodal throtle parameter (btp). 49 * 50 * From the original paper, this implementation of RRIP is also called |
51 * Static RRIP (SRRIP), as it always inserts blocks with the same RRPV. | 51 * Static RRIP (SRRIP), as it always inserts entries with the same RRPV. |
52 */ 53 54#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_BRRIP_RP_HH__ 55#define __MEM_CACHE_REPLACEMENT_POLICIES_BRRIP_RP_HH__ 56 57#include "mem/cache/replacement_policies/base.hh" 58#include "params/BRRIPRP.hh" 59 60class BRRIPRP : public BaseReplacementPolicy 61{ 62 protected: | 52 */ 53 54#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_BRRIP_RP_HH__ 55#define __MEM_CACHE_REPLACEMENT_POLICIES_BRRIP_RP_HH__ 56 57#include "mem/cache/replacement_policies/base.hh" 58#include "params/BRRIPRP.hh" 59 60class BRRIPRP : public BaseReplacementPolicy 61{ 62 protected: |
63 /** BRRIP-specific implementation of replacement data. */ 64 struct BRRIPReplData : ReplacementData 65 { 66 /** 67 * Re-Reference Interval Prediction Value. 68 * A value equal to max_RRPV + 1 indicates an invalid entry. 69 */ 70 int rrpv; 71 72 /** 73 * Default constructor. Invalidate data. 74 */ 75 BRRIPReplData(const int max_RRPV) : rrpv(max_RRPV + 1) {} 76 }; 77 |
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63 /** | 78 /** |
64 * Maximum Re-Reference Prediction Value possible. A block with this | 79 * Maximum Re-Reference Prediction Value possible. An entry with this |
65 * value as the rrpv has the longest possible re-reference interval, 66 * that is, it is likely not to be used in the near future, and is 67 * among the best eviction candidates. 68 * A maxRRPV of 1 implies in a NRU. 69 */ | 80 * value as the rrpv has the longest possible re-reference interval, 81 * that is, it is likely not to be used in the near future, and is 82 * among the best eviction candidates. 83 * A maxRRPV of 1 implies in a NRU. 84 */ |
70 const unsigned maxRRPV; | 85 const int maxRRPV; |
71 72 /** | 86 87 /** |
73 * The hit priority (HP) policy replaces blocks that do not receive cache 74 * hits over any cache block that receives a hit, while the frequency 75 * priority (FP) policy replaces infrequently re-referenced blocks. | 88 * The hit priority (HP) policy replaces entries that do not receive cache 89 * hits over any cache entry that receives a hit, while the frequency 90 * priority (FP) policy replaces infrequently re-referenced entries. |
76 */ 77 const bool hitPriority; 78 79 /** 80 * Bimodal throtle parameter. Value in the range [0,100] used to decide | 91 */ 92 const bool hitPriority; 93 94 /** 95 * Bimodal throtle parameter. Value in the range [0,100] used to decide |
81 * if a new block is inserted with long or distant re-reference. | 96 * if a new entry is inserted with long or distant re-reference. |
82 */ 83 const unsigned btp; 84 85 public: 86 /** Convenience typedef. */ 87 typedef BRRIPRPParams Params; 88 89 /** 90 * Construct and initiliaze this replacement policy. 91 */ 92 BRRIPRP(const Params *p); 93 94 /** 95 * Destructor. 96 */ 97 ~BRRIPRP() {} 98 99 /** | 97 */ 98 const unsigned btp; 99 100 public: 101 /** Convenience typedef. */ 102 typedef BRRIPRPParams Params; 103 104 /** 105 * Construct and initiliaze this replacement policy. 106 */ 107 BRRIPRP(const Params *p); 108 109 /** 110 * Destructor. 111 */ 112 ~BRRIPRP() {} 113 114 /** |
100 * Touch a block to update its replacement data. | 115 * Invalidate replacement data to set it as the next probable victim. 116 * Set RRPV as the the most distant re-reference. |
101 * | 117 * |
102 * @param blk Cache block to be touched. | 118 * @param replacement_data Replacement data to be invalidated. |
103 */ | 119 */ |
104 void touch(CacheBlk *blk) override; | 120 void invalidate(const std::shared_ptr<ReplacementData>& replacement_data) 121 const override; |
105 106 /** | 122 123 /** |
107 * Reset replacement data for a block. Used when a block is inserted. 108 * Sets the insertion tick, and update correspondent replacement data. | 124 * Touch an entry to update its replacement data. 125 * 126 * @param replacement_data Replacement data to be touched. 127 */ 128 void touch(const std::shared_ptr<ReplacementData>& replacement_data) const 129 override; 130 131 /** 132 * Reset replacement data. Used when an entry is inserted. |
109 * Set RRPV according to the insertion policy used. 110 * | 133 * Set RRPV according to the insertion policy used. 134 * |
111 * @param blk Cache block to be reset. | 135 * @param replacement_data Replacement data to be reset. |
112 */ | 136 */ |
113 void reset(CacheBlk *blk) override; | 137 void reset(const std::shared_ptr<ReplacementData>& replacement_data) const 138 override; |
114 115 /** 116 * Find replacement victim using rrpv. 117 * 118 * @param cands Replacement candidates, selected by indexing policy. | 139 140 /** 141 * Find replacement victim using rrpv. 142 * 143 * @param cands Replacement candidates, selected by indexing policy. |
119 * @return Cache block to be replaced. | 144 * @return Replacement entry to be replaced. |
120 */ | 145 */ |
121 CacheBlk* getVictim(const ReplacementCandidates& candidates) override; | 146 ReplaceableEntry* getVictim(const ReplacementCandidates& candidates) const 147 override; 148 149 /** 150 * Instantiate a replacement data entry. 151 * 152 * @return A shared pointer to the new replacement data. 153 */ 154 std::shared_ptr<ReplacementData> instantiateEntry() override; |
122}; 123 124#endif // __MEM_CACHE_REPLACEMENT_POLICIES_BRRIP_RP_HH__ | 155}; 156 157#endif // __MEM_CACHE_REPLACEMENT_POLICIES_BRRIP_RP_HH__ |