rob.hh revision 9954:72a72649a156
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 protected: 64 typedef TheISA::RegIndex RegIndex; 65 public: 66 //Typedefs from the Impl. 67 typedef typename Impl::O3CPU O3CPU; 68 typedef typename Impl::DynInstPtr DynInstPtr; 69 70 typedef std::pair<RegIndex, PhysRegIndex> UnmapInfo; 71 typedef typename std::list<DynInstPtr>::iterator InstIt; 72 73 /** Possible ROB statuses. */ 74 enum Status { 75 Running, 76 Idle, 77 ROBSquashing 78 }; 79 80 /** SMT ROB Sharing Policy */ 81 enum ROBPolicy{ 82 Dynamic, 83 Partitioned, 84 Threshold 85 }; 86 87 private: 88 /** Per-thread ROB status. */ 89 Status robStatus[Impl::MaxThreads]; 90 91 /** ROB resource sharing policy for SMT mode. */ 92 ROBPolicy robPolicy; 93 94 public: 95 /** ROB constructor. 96 * @param _cpu The cpu object pointer. 97 * @param params The cpu params including several ROB-specific parameters. 98 */ 99 ROB(O3CPU *_cpu, DerivO3CPUParams *params); 100 101 std::string name() const; 102 103 /** Sets pointer to the list of active threads. 104 * @param at_ptr Pointer to the list of active threads. 105 */ 106 void setActiveThreads(std::list<ThreadID> *at_ptr); 107 108 /** Perform sanity checks after a drain. */ 109 void drainSanityCheck() const; 110 111 /** Takes over another CPU's thread. */ 112 void takeOverFrom(); 113 114 /** Function to insert an instruction into the ROB. Note that whatever 115 * calls this function must ensure that there is enough space within the 116 * ROB for the new instruction. 117 * @param inst The instruction being inserted into the ROB. 118 */ 119 void insertInst(DynInstPtr &inst); 120 121 /** Returns pointer to the head instruction within the ROB. There is 122 * no guarantee as to the return value if the ROB is empty. 123 * @retval Pointer to the DynInst that is at the head of the ROB. 124 */ 125// DynInstPtr readHeadInst(); 126 127 /** Returns a pointer to the head instruction of a specific thread within 128 * the ROB. 129 * @return Pointer to the DynInst that is at the head of the ROB. 130 */ 131 DynInstPtr readHeadInst(ThreadID tid); 132 133 /** Returns a pointer to the instruction with the given sequence if it is 134 * in the ROB. 135 */ 136 DynInstPtr findInst(ThreadID tid, InstSeqNum squash_inst); 137 138 /** Returns pointer to the tail instruction within the ROB. There is 139 * no guarantee as to the return value if the ROB is empty. 140 * @retval Pointer to the DynInst that is at the tail of the ROB. 141 */ 142// DynInstPtr readTailInst(); 143 144 /** Returns a pointer to the tail instruction of a specific thread within 145 * the ROB. 146 * @return Pointer to the DynInst that is at the tail of the ROB. 147 */ 148 DynInstPtr readTailInst(ThreadID tid); 149 150 /** Retires the head instruction, removing it from the ROB. */ 151// void retireHead(); 152 153 /** Retires the head instruction of a specific thread, removing it from the 154 * ROB. 155 */ 156 void retireHead(ThreadID tid); 157 158 /** Is the oldest instruction across all threads ready. */ 159// bool isHeadReady(); 160 161 /** Is the oldest instruction across a particular thread ready. */ 162 bool isHeadReady(ThreadID tid); 163 164 /** Is there any commitable head instruction across all threads ready. */ 165 bool canCommit(); 166 167 /** Re-adjust ROB partitioning. */ 168 void resetEntries(); 169 170 /** Number of entries needed For 'num_threads' amount of threads. */ 171 int entryAmount(ThreadID num_threads); 172 173 /** Returns the number of total free entries in the ROB. */ 174 unsigned numFreeEntries(); 175 176 /** Returns the number of free entries in a specific ROB paritition. */ 177 unsigned numFreeEntries(ThreadID tid); 178 179 /** Returns the maximum number of entries for a specific thread. */ 180 unsigned getMaxEntries(ThreadID tid) 181 { return maxEntries[tid]; } 182 183 /** Returns the number of entries being used by a specific thread. */ 184 unsigned getThreadEntries(ThreadID tid) 185 { return threadEntries[tid]; } 186 187 /** Returns if the ROB is full. */ 188 bool isFull() 189 { return numInstsInROB == numEntries; } 190 191 /** Returns if a specific thread's partition is full. */ 192 bool isFull(ThreadID tid) 193 { return threadEntries[tid] == numEntries; } 194 195 /** Returns if the ROB is empty. */ 196 bool isEmpty() const 197 { return numInstsInROB == 0; } 198 199 /** Returns if a specific thread's partition is empty. */ 200 bool isEmpty(ThreadID tid) const 201 { return threadEntries[tid] == 0; } 202 203 /** Executes the squash, marking squashed instructions. */ 204 void doSquash(ThreadID tid); 205 206 /** Squashes all instructions younger than the given sequence number for 207 * the specific thread. 208 */ 209 void squash(InstSeqNum squash_num, ThreadID tid); 210 211 /** Updates the head instruction with the new oldest instruction. */ 212 void updateHead(); 213 214 /** Updates the tail instruction with the new youngest instruction. */ 215 void updateTail(); 216 217 /** Reads the PC of the oldest head instruction. */ 218// uint64_t readHeadPC(); 219 220 /** Reads the PC of the head instruction of a specific thread. */ 221// uint64_t readHeadPC(ThreadID tid); 222 223 /** Reads the next PC of the oldest head instruction. */ 224// uint64_t readHeadNextPC(); 225 226 /** Reads the next PC of the head instruction of a specific thread. */ 227// uint64_t readHeadNextPC(ThreadID tid); 228 229 /** Reads the sequence number of the oldest head instruction. */ 230// InstSeqNum readHeadSeqNum(); 231 232 /** Reads the sequence number of the head instruction of a specific thread. 233 */ 234// InstSeqNum readHeadSeqNum(ThreadID tid); 235 236 /** Reads the PC of the youngest tail instruction. */ 237// uint64_t readTailPC(); 238 239 /** Reads the PC of the tail instruction of a specific thread. */ 240// uint64_t readTailPC(ThreadID tid); 241 242 /** Reads the sequence number of the youngest tail instruction. */ 243// InstSeqNum readTailSeqNum(); 244 245 /** Reads the sequence number of tail instruction of a specific thread. */ 246// InstSeqNum readTailSeqNum(ThreadID tid); 247 248 /** Checks if the ROB is still in the process of squashing instructions. 249 * @retval Whether or not the ROB is done squashing. 250 */ 251 bool isDoneSquashing(ThreadID tid) const 252 { return doneSquashing[tid]; } 253 254 /** Checks if the ROB is still in the process of squashing instructions for 255 * any thread. 256 */ 257 bool isDoneSquashing(); 258 259 /** This is more of a debugging function than anything. Use 260 * numInstsInROB to get the instructions in the ROB unless you are 261 * double checking that variable. 262 */ 263 int countInsts(); 264 265 /** This is more of a debugging function than anything. Use 266 * threadEntries to get the instructions in the ROB unless you are 267 * double checking that variable. 268 */ 269 int countInsts(ThreadID tid); 270 271 /** Registers statistics. */ 272 void regStats(); 273 274 private: 275 /** Reset the ROB state */ 276 void resetState(); 277 278 /** Pointer to the CPU. */ 279 O3CPU *cpu; 280 281 /** Active Threads in CPU */ 282 std::list<ThreadID> *activeThreads; 283 284 /** Number of instructions in the ROB. */ 285 unsigned numEntries; 286 287 /** Entries Per Thread */ 288 unsigned threadEntries[Impl::MaxThreads]; 289 290 /** Max Insts a Thread Can Have in the ROB */ 291 unsigned maxEntries[Impl::MaxThreads]; 292 293 /** ROB List of Instructions */ 294 std::list<DynInstPtr> instList[Impl::MaxThreads]; 295 296 /** Number of instructions that can be squashed in a single cycle. */ 297 unsigned squashWidth; 298 299 public: 300 /** Iterator pointing to the instruction which is the last instruction 301 * in the ROB. This may at times be invalid (ie when the ROB is empty), 302 * however it should never be incorrect. 303 */ 304 InstIt tail; 305 306 /** Iterator pointing to the instruction which is the first instruction in 307 * in the ROB*/ 308 InstIt head; 309 310 private: 311 /** Iterator used for walking through the list of instructions when 312 * squashing. Used so that there is persistent state between cycles; 313 * when squashing, the instructions are marked as squashed but not 314 * immediately removed, meaning the tail iterator remains the same before 315 * and after a squash. 316 * This will always be set to cpu->instList.end() if it is invalid. 317 */ 318 InstIt squashIt[Impl::MaxThreads]; 319 320 public: 321 /** Number of instructions in the ROB. */ 322 int numInstsInROB; 323 324 /** Dummy instruction returned if there are no insts left. */ 325 DynInstPtr dummyInst; 326 327 private: 328 /** The sequence number of the squashed instruction. */ 329 InstSeqNum squashedSeqNum[Impl::MaxThreads]; 330 331 /** Is the ROB done squashing. */ 332 bool doneSquashing[Impl::MaxThreads]; 333 334 /** Number of active threads. */ 335 ThreadID numThreads; 336 337 // The number of rob_reads 338 Stats::Scalar robReads; 339 // The number of rob_writes 340 Stats::Scalar robWrites; 341}; 342 343#endif //__CPU_O3_ROB_HH__ 344