fu_pool.hh revision 7813
1/* 2 * Copyright (c) 2006 The Regents of The University of Michigan 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: Kevin Lim 29 */ 30 31#ifndef __CPU_O3_FU_POOL_HH__ 32#define __CPU_O3_FU_POOL_HH__ 33 34#include <bitset> 35#include <list> 36#include <string> 37#include <vector> 38 39#include "cpu/sched_list.hh" 40#include "cpu/op_class.hh" 41#include "params/FUPool.hh" 42#include "sim/sim_object.hh" 43 44class FUDesc; 45class FuncUnit; 46 47/** 48 * Pool of FU's, specific to the new CPU model. The old FU pool had lists of 49 * free units and busy units, and whenever a FU was needed it would iterate 50 * through the free units to find a FU that provided the capability. This pool 51 * has lists of units specific to each of the capabilities, and whenever a FU 52 * is needed, it iterates through that list to find a free unit. The previous 53 * FU pool would have to be ticked each cycle to update which units became 54 * free. This FU pool lets the IEW stage handle freeing units, which frees 55 * them as their scheduled execution events complete. This limits units in this 56 * model to either have identical issue and op latencies, or 1 cycle issue 57 * latencies. 58 */ 59class FUPool : public SimObject 60{ 61 private: 62 /** Maximum op execution latencies, per op class. */ 63 unsigned maxOpLatencies[Num_OpClasses]; 64 /** Maximum issue latencies, per op class. */ 65 unsigned maxIssueLatencies[Num_OpClasses]; 66 67 /** Bitvector listing capabilities of this FU pool. */ 68 std::bitset<Num_OpClasses> capabilityList; 69 70 /** Bitvector listing which FUs are busy. */ 71 std::vector<bool> unitBusy; 72 73 /** List of units to be freed at the end of this cycle. */ 74 std::vector<int> unitsToBeFreed; 75 76 /** 77 * Class that implements a circular queue to hold FU indices. The hope is 78 * that FUs that have been just used will be moved to the end of the queue 79 * by iterating through it, thus leaving free units at the head of the 80 * queue. 81 */ 82 class FUIdxQueue { 83 public: 84 /** Constructs a circular queue of FU indices. */ 85 FUIdxQueue() 86 : idx(0), size(0) 87 { } 88 89 /** Adds a FU to the queue. */ 90 inline void addFU(int fu_idx); 91 92 /** Returns the index of the FU at the head of the queue, and changes 93 * the index to the next element. 94 */ 95 inline int getFU(); 96 97 private: 98 /** Circular queue index. */ 99 int idx; 100 101 /** Size of the queue. */ 102 int size; 103 104 /** Queue of FU indices. */ 105 std::vector<int> funcUnitsIdx; 106 }; 107 108 /** Per op class queues of FUs that provide that capability. */ 109 FUIdxQueue fuPerCapList[Num_OpClasses]; 110 111 /** Number of FUs. */ 112 int numFU; 113 114 /** Functional units. */ 115 std::vector<FuncUnit *> funcUnits; 116 117 typedef std::vector<FuncUnit *>::iterator fuListIterator; 118 119 public: 120 typedef FUPoolParams Params; 121 /** Constructs a FU pool. */ 122 FUPool(const Params *p); 123 ~FUPool(); 124 125 /** Annotates units that provide memory operations. Included only because 126 * old FU pool provided this function. 127 */ 128 void annotateMemoryUnits(unsigned hit_latency); 129 130 /** 131 * Gets a FU providing the requested capability. Will mark the unit as busy, 132 * but leaves the freeing of the unit up to the IEW stage. 133 * @param capability The capability requested. 134 * @return Returns -2 if the FU pool does not have the capability, -1 if 135 * there is no free FU, and the FU's index otherwise. 136 */ 137 int getUnit(OpClass capability); 138 139 /** Frees a FU at the end of this cycle. */ 140 void freeUnitNextCycle(int fu_idx); 141 142 /** Frees all FUs on the list. */ 143 void processFreeUnits(); 144 145 /** Returns the total number of FUs. */ 146 int size() { return numFU; } 147 148 /** Debugging function used to dump FU information. */ 149 void dump(); 150 151 /** Returns the operation execution latency of the given capability. */ 152 unsigned getOpLatency(OpClass capability) { 153 return maxOpLatencies[capability]; 154 } 155 156 /** Returns the issue latency of the given capability. */ 157 unsigned getIssueLatency(OpClass capability) { 158 return maxIssueLatencies[capability]; 159 } 160 161 /** Switches out functional unit pool. */ 162 void switchOut(); 163 164 /** Takes over from another CPU's thread. */ 165 void takeOverFrom(); 166}; 167 168#endif // __CPU_O3_FU_POOL_HH__ 169