mshr_queue.hh revision 9347:b02075171b57
1/* 2 * Copyright (c) 2012 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) 2003-2005 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: Erik Hallnor 41 * Andreas Sandberg 42 */ 43 44/** @file 45 * Declaration of a structure to manage MSHRs. 46 */ 47 48#ifndef __MEM__CACHE__MISS__MSHR_QUEUE_HH__ 49#define __MEM__CACHE__MISS__MSHR_QUEUE_HH__ 50 51#include <vector> 52 53#include "mem/cache/mshr.hh" 54#include "mem/packet.hh" 55#include "sim/drain.hh" 56 57/** 58 * A Class for maintaining a list of pending and allocated memory requests. 59 */ 60class MSHRQueue : public Drainable 61{ 62 private: 63 /** Local label (for functional print requests) */ 64 const std::string label; 65 66 /** MSHR storage. */ 67 MSHR *registers; 68 /** Holds pointers to all allocated entries. */ 69 MSHR::List allocatedList; 70 /** Holds pointers to entries that haven't been sent to the bus. */ 71 MSHR::List readyList; 72 /** Holds non allocated entries. */ 73 MSHR::List freeList; 74 75 // Parameters 76 /** 77 * The total number of entries in this queue. This number is set as the 78 * number of entries requested plus (numReserve - 1). This allows for 79 * the same number of effective entries while still maintaining the reserve. 80 */ 81 const int numEntries; 82 83 /** 84 * The number of entries to hold in reserve. This is needed because copy 85 * operations can allocate upto 4 entries at one time. 86 */ 87 const int numReserve; 88 89 /** Drain manager to inform of a completed drain */ 90 DrainManager *drainManager; 91 92 MSHR::Iterator addToReadyList(MSHR *mshr); 93 94 95 public: 96 /** The number of allocated entries. */ 97 int allocated; 98 /** The number of entries that have been forwarded to the bus. */ 99 int inServiceEntries; 100 /** The index of this queue within the cache (MSHR queue vs. write 101 * buffer). */ 102 const int index; 103 104 /** 105 * Create a queue with a given number of entries. 106 * @param num_entrys The number of entries in this queue. 107 * @param reserve The minimum number of entries needed to satisfy 108 * any access. 109 */ 110 MSHRQueue(const std::string &_label, int num_entries, int reserve, 111 int index); 112 113 /** Destructor */ 114 ~MSHRQueue(); 115 116 /** 117 * Find the first MSHR that matches the provided address. 118 * @param addr The address to find. 119 * @return Pointer to the matching MSHR, null if not found. 120 */ 121 MSHR *findMatch(Addr addr) const; 122 123 /** 124 * Find and return all the matching entries in the provided vector. 125 * @param addr The address to find. 126 * @param matches The vector to return pointers to the matching entries. 127 * @return True if any matches are found, false otherwise. 128 * @todo Typedef the vector?? 129 */ 130 bool findMatches(Addr addr, std::vector<MSHR*>& matches) const; 131 132 /** 133 * Find any pending requests that overlap the given request. 134 * @param pkt The request to find. 135 * @return A pointer to the earliest matching MSHR. 136 */ 137 MSHR *findPending(Addr addr, int size) const; 138 139 bool checkFunctional(PacketPtr pkt, Addr blk_addr); 140 141 /** 142 * Allocates a new MSHR for the request and size. This places the request 143 * as the first target in the MSHR. 144 * @param pkt The request to handle. 145 * @param size The number in bytes to fetch from memory. 146 * @return The a pointer to the MSHR allocated. 147 * 148 * @pre There are free entries. 149 */ 150 MSHR *allocate(Addr addr, int size, PacketPtr &pkt, 151 Tick when, Counter order); 152 153 /** 154 * Removes the given MSHR from the queue. This places the MSHR on the 155 * free list. 156 * @param mshr 157 */ 158 void deallocate(MSHR *mshr); 159 160 /** 161 * Remove a MSHR from the queue. Returns an iterator into the 162 * allocatedList for faster squash implementation. 163 * @param mshr The MSHR to remove. 164 * @return An iterator to the next entry in the allocatedList. 165 */ 166 MSHR::Iterator deallocateOne(MSHR *mshr); 167 168 /** 169 * Moves the MSHR to the front of the pending list if it is not 170 * in service. 171 * @param mshr The entry to move. 172 */ 173 void moveToFront(MSHR *mshr); 174 175 /** 176 * Mark the given MSHR as in service. This removes the MSHR from the 177 * readyList. Deallocates the MSHR if it does not expect a response. 178 * @param mshr The MSHR to mark in service. 179 */ 180 void markInService(MSHR *mshr, PacketPtr pkt); 181 182 /** 183 * Mark an in service entry as pending, used to resend a request. 184 * @param mshr The MSHR to resend. 185 */ 186 void markPending(MSHR *mshr); 187 188 /** 189 * Squash outstanding requests with the given thread number. If a request 190 * is in service, just squashes the targets. 191 * @param threadNum The thread to squash. 192 */ 193 void squash(int threadNum); 194 195 /** 196 * Returns true if the pending list is not empty. 197 * @return True if there are outstanding requests. 198 */ 199 bool havePending() const 200 { 201 return !readyList.empty(); 202 } 203 204 /** 205 * Returns true if there are no free entries. 206 * @return True if this queue is full. 207 */ 208 bool isFull() const 209 { 210 return (allocated > numEntries - numReserve); 211 } 212 213 /** 214 * Returns the MSHR at the head of the readyList. 215 * @return The next request to service. 216 */ 217 MSHR *getNextMSHR() const 218 { 219 if (readyList.empty() || readyList.front()->readyTime > curTick()) { 220 return NULL; 221 } 222 return readyList.front(); 223 } 224 225 Tick nextMSHRReadyTime() const 226 { 227 return readyList.empty() ? MaxTick : readyList.front()->readyTime; 228 } 229 230 unsigned int drain(DrainManager *dm); 231}; 232 233#endif //__MEM__CACHE__MISS__MSHR_QUEUE_HH__ 234