rob.hh revision 13429:a1e199fd8122
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) 2004-2006 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: Kevin Lim 41 * Korey Sewell 42 */ 43 44#ifndef __CPU_O3_ROB_HH__ 45#define __CPU_O3_ROB_HH__ 46 47#include <string> 48#include <utility> 49#include <vector> 50 51#include "arch/registers.hh" 52#include "base/types.hh" 53#include "config/the_isa.hh" 54 55struct DerivO3CPUParams; 56 57/** 58 * ROB class. The ROB is largely what drives squashing. 59 */ 60template <class Impl> 61class ROB 62{ 63 public: 64 //Typedefs from the Impl. 65 typedef typename Impl::O3CPU O3CPU; 66 typedef typename Impl::DynInstPtr DynInstPtr; 67 68 typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo; 69 typedef typename std::list<DynInstPtr>::iterator InstIt; 70 71 /** Possible ROB statuses. */ 72 enum Status { 73 Running, 74 Idle, 75 ROBSquashing 76 }; 77 78 /** SMT ROB Sharing Policy */ 79 enum ROBPolicy{ 80 Dynamic, 81 Partitioned, 82 Threshold 83 }; 84 85 private: 86 /** Per-thread ROB status. */ 87 Status robStatus[Impl::MaxThreads]; 88 89 /** ROB resource sharing policy for SMT mode. */ 90 ROBPolicy robPolicy; 91 92 public: 93 /** ROB constructor. 94 * @param _cpu The cpu object pointer. 95 * @param params The cpu params including several ROB-specific parameters. 96 */ 97 ROB(O3CPU *_cpu, DerivO3CPUParams *params); 98 99 std::string name() const; 100 101 /** Sets pointer to the list of active threads. 102 * @param at_ptr Pointer to the list of active threads. 103 */ 104 void setActiveThreads(std::list<ThreadID> *at_ptr); 105 106 /** Perform sanity checks after a drain. */ 107 void drainSanityCheck() const; 108 109 /** Takes over another CPU's thread. */ 110 void takeOverFrom(); 111 112 /** Function to insert an instruction into the ROB. Note that whatever 113 * calls this function must ensure that there is enough space within the 114 * ROB for the new instruction. 115 * @param inst The instruction being inserted into the ROB. 116 */ 117 void insertInst(const DynInstPtr &inst); 118 119 /** Returns pointer to the head instruction within the ROB. There is 120 * no guarantee as to the return value if the ROB is empty. 121 * @retval Pointer to the DynInst that is at the head of the ROB. 122 */ 123// DynInstPtr readHeadInst(); 124 125 /** Returns a pointer to the head instruction of a specific thread within 126 * the ROB. 127 * @return Pointer to the DynInst that is at the head of the ROB. 128 */ 129 const DynInstPtr &readHeadInst(ThreadID tid); 130 131 /** Returns a pointer to the instruction with the given sequence if it is 132 * in the ROB. 133 */ 134 DynInstPtr findInst(ThreadID tid, InstSeqNum squash_inst); 135 136 /** Returns pointer to the tail instruction within the ROB. There is 137 * no guarantee as to the return value if the ROB is empty. 138 * @retval Pointer to the DynInst that is at the tail of the ROB. 139 */ 140// DynInstPtr readTailInst(); 141 142 /** Returns a pointer to the tail instruction of a specific thread within 143 * the ROB. 144 * @return Pointer to the DynInst that is at the tail of the ROB. 145 */ 146 DynInstPtr readTailInst(ThreadID tid); 147 148 /** Retires the head instruction, removing it from the ROB. */ 149// void retireHead(); 150 151 /** Retires the head instruction of a specific thread, removing it from the 152 * ROB. 153 */ 154 void retireHead(ThreadID tid); 155 156 /** Is the oldest instruction across all threads ready. */ 157// bool isHeadReady(); 158 159 /** Is the oldest instruction across a particular thread ready. */ 160 bool isHeadReady(ThreadID tid); 161 162 /** Is there any commitable head instruction across all threads ready. */ 163 bool canCommit(); 164 165 /** Re-adjust ROB partitioning. */ 166 void resetEntries(); 167 168 /** Number of entries needed For 'num_threads' amount of threads. */ 169 int entryAmount(ThreadID num_threads); 170 171 /** Returns the number of total free entries in the ROB. */ 172 unsigned numFreeEntries(); 173 174 /** Returns the number of free entries in a specific ROB paritition. */ 175 unsigned numFreeEntries(ThreadID tid); 176 177 /** Returns the maximum number of entries for a specific thread. */ 178 unsigned getMaxEntries(ThreadID tid) 179 { return maxEntries[tid]; } 180 181 /** Returns the number of entries being used by a specific thread. */ 182 unsigned getThreadEntries(ThreadID tid) 183 { return threadEntries[tid]; } 184 185 /** Returns if the ROB is full. */ 186 bool isFull() 187 { return numInstsInROB == numEntries; } 188 189 /** Returns if a specific thread's partition is full. */ 190 bool isFull(ThreadID tid) 191 { return threadEntries[tid] == numEntries; } 192 193 /** Returns if the ROB is empty. */ 194 bool isEmpty() const 195 { return numInstsInROB == 0; } 196 197 /** Returns if a specific thread's partition is empty. */ 198 bool isEmpty(ThreadID tid) const 199 { return threadEntries[tid] == 0; } 200 201 /** Executes the squash, marking squashed instructions. */ 202 void doSquash(ThreadID tid); 203 204 /** Squashes all instructions younger than the given sequence number for 205 * the specific thread. 206 */ 207 void squash(InstSeqNum squash_num, ThreadID tid); 208 209 /** Updates the head instruction with the new oldest instruction. */ 210 void updateHead(); 211 212 /** Updates the tail instruction with the new youngest instruction. */ 213 void updateTail(); 214 215 /** Reads the PC of the oldest head instruction. */ 216// uint64_t readHeadPC(); 217 218 /** Reads the PC of the head instruction of a specific thread. */ 219// uint64_t readHeadPC(ThreadID tid); 220 221 /** Reads the next PC of the oldest head instruction. */ 222// uint64_t readHeadNextPC(); 223 224 /** Reads the next PC of the head instruction of a specific thread. */ 225// uint64_t readHeadNextPC(ThreadID tid); 226 227 /** Reads the sequence number of the oldest head instruction. */ 228// InstSeqNum readHeadSeqNum(); 229 230 /** Reads the sequence number of the head instruction of a specific thread. 231 */ 232// InstSeqNum readHeadSeqNum(ThreadID tid); 233 234 /** Reads the PC of the youngest tail instruction. */ 235// uint64_t readTailPC(); 236 237 /** Reads the PC of the tail instruction of a specific thread. */ 238// uint64_t readTailPC(ThreadID tid); 239 240 /** Reads the sequence number of the youngest tail instruction. */ 241// InstSeqNum readTailSeqNum(); 242 243 /** Reads the sequence number of tail instruction of a specific thread. */ 244// InstSeqNum readTailSeqNum(ThreadID tid); 245 246 /** Checks if the ROB is still in the process of squashing instructions. 247 * @retval Whether or not the ROB is done squashing. 248 */ 249 bool isDoneSquashing(ThreadID tid) const 250 { return doneSquashing[tid]; } 251 252 /** Checks if the ROB is still in the process of squashing instructions for 253 * any thread. 254 */ 255 bool isDoneSquashing(); 256 257 /** This is more of a debugging function than anything. Use 258 * numInstsInROB to get the instructions in the ROB unless you are 259 * double checking that variable. 260 */ 261 int countInsts(); 262 263 /** This is more of a debugging function than anything. Use 264 * threadEntries to get the instructions in the ROB unless you are 265 * double checking that variable. 266 */ 267 int countInsts(ThreadID tid); 268 269 /** Registers statistics. */ 270 void regStats(); 271 272 private: 273 /** Reset the ROB state */ 274 void resetState(); 275 276 /** Pointer to the CPU. */ 277 O3CPU *cpu; 278 279 /** Active Threads in CPU */ 280 std::list<ThreadID> *activeThreads; 281 282 /** Number of instructions in the ROB. */ 283 unsigned numEntries; 284 285 /** Entries Per Thread */ 286 unsigned threadEntries[Impl::MaxThreads]; 287 288 /** Max Insts a Thread Can Have in the ROB */ 289 unsigned maxEntries[Impl::MaxThreads]; 290 291 /** ROB List of Instructions */ 292 std::list<DynInstPtr> instList[Impl::MaxThreads]; 293 294 /** Number of instructions that can be squashed in a single cycle. */ 295 unsigned squashWidth; 296 297 public: 298 /** Iterator pointing to the instruction which is the last instruction 299 * in the ROB. This may at times be invalid (ie when the ROB is empty), 300 * however it should never be incorrect. 301 */ 302 InstIt tail; 303 304 /** Iterator pointing to the instruction which is the first instruction in 305 * in the ROB*/ 306 InstIt head; 307 308 private: 309 /** Iterator used for walking through the list of instructions when 310 * squashing. Used so that there is persistent state between cycles; 311 * when squashing, the instructions are marked as squashed but not 312 * immediately removed, meaning the tail iterator remains the same before 313 * and after a squash. 314 * This will always be set to cpu->instList.end() if it is invalid. 315 */ 316 InstIt squashIt[Impl::MaxThreads]; 317 318 public: 319 /** Number of instructions in the ROB. */ 320 int numInstsInROB; 321 322 /** Dummy instruction returned if there are no insts left. */ 323 DynInstPtr dummyInst; 324 325 private: 326 /** The sequence number of the squashed instruction. */ 327 InstSeqNum squashedSeqNum[Impl::MaxThreads]; 328 329 /** Is the ROB done squashing. */ 330 bool doneSquashing[Impl::MaxThreads]; 331 332 /** Number of active threads. */ 333 ThreadID numThreads; 334 335 // The number of rob_reads 336 Stats::Scalar robReads; 337 // The number of rob_writes 338 Stats::Scalar robWrites; 339}; 340 341#endif //__CPU_O3_ROB_HH__ 342