stride.hh revision 13426
1/* 2 * Copyright (c) 2012-2013, 2015 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2005 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Ron Dreslinski 41 */ 42 43/** 44 * @file 45 * Describes a strided prefetcher. 46 */ 47 48#ifndef __MEM_CACHE_PREFETCH_STRIDE_HH__ 49#define __MEM_CACHE_PREFETCH_STRIDE_HH__ 50 51#include <string> 52#include <unordered_map> 53#include <vector> 54 55#include "base/types.hh" 56#include "mem/cache/prefetch/queued.hh" 57#include "mem/packet.hh" 58 59struct StridePrefetcherParams; 60 61class StridePrefetcher : public QueuedPrefetcher 62{ 63 protected: 64 const int maxConf; 65 const int threshConf; 66 const int minConf; 67 const int startConf; 68 69 const int pcTableAssoc; 70 const int pcTableSets; 71 72 const bool useMasterId; 73 74 const int degree; 75 76 struct StrideEntry 77 { 78 /** Default constructor */ 79 StrideEntry(); 80 81 /** Invalidate the entry */ 82 void invalidate(); 83 84 Addr instAddr; 85 Addr lastAddr; 86 bool isSecure; 87 int stride; 88 int confidence; 89 }; 90 91 class PCTable 92 { 93 public: 94 /** 95 * Default constructor. Create a table with given parameters. 96 * 97 * @param assoc Associativity of the table. 98 * @param sets Number of sets in the table. 99 * @param name Name of the prefetcher. 100 */ 101 PCTable(int assoc, int sets, const std::string name); 102 103 /** 104 * Default destructor. 105 */ 106 ~PCTable(); 107 108 /** 109 * Search for an entry in the pc table. 110 * 111 * @param pc The PC to look for. 112 * @param is_secure True if the target memory space is secure. 113 * @return Pointer to the entry. 114 */ 115 StrideEntry* findEntry(Addr pc, bool is_secure); 116 117 /** 118 * Find a replacement victim to make room for given PC. 119 * 120 * @param pc The PC value. 121 * @return The victimized entry. 122 */ 123 StrideEntry* findVictim(Addr pc); 124 125 private: 126 const std::string name() {return _name; } 127 const int pcTableAssoc; 128 const int pcTableSets; 129 const std::string _name; 130 std::vector<std::vector<StrideEntry>> entries; 131 132 /** 133 * PC hashing function to index sets in the table. 134 * 135 * @param pc The PC value. 136 * @return The set to which this PC maps. 137 */ 138 Addr pcHash(Addr pc) const; 139 }; 140 std::unordered_map<int, PCTable> pcTables; 141 142 /** 143 * Try to find a table of entries for the given context. If none is 144 * found, a new table is created. 145 * 146 * @param context The context to be searched for. 147 * @return The table corresponding to the given context. 148 */ 149 PCTable* findTable(int context); 150 151 /** 152 * Create a PC table for the given context. 153 * 154 * @param context The context of the new PC table. 155 * @return The new PC table 156 */ 157 PCTable* allocateNewContext(int context); 158 159 public: 160 StridePrefetcher(const StridePrefetcherParams *p); 161 162 void calculatePrefetch(const PacketPtr &pkt, 163 std::vector<AddrPriority> &addresses) override; 164}; 165 166#endif // __MEM_CACHE_PREFETCH_STRIDE_HH__ 167