1/* 2 * Copyright (c) 2010-2014 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) 2013 Amin Farmahini-Farahani 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: Andreas Hansson 41 * Ani Udipi 42 * Neha Agarwal 43 */ 44 45#include "base/bitfield.hh" 46#include "base/trace.hh" 47#include "debug/DRAM.hh"
| 1/* 2 * Copyright (c) 2010-2014 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) 2013 Amin Farmahini-Farahani 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: Andreas Hansson 41 * Ani Udipi 42 * Neha Agarwal 43 */ 44 45#include "base/bitfield.hh" 46#include "base/trace.hh" 47#include "debug/DRAM.hh"
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| 48#include "debug/DRAMState.hh"
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48#include "debug/Drain.hh" 49#include "mem/dram_ctrl.hh" 50#include "sim/system.hh" 51 52using namespace std; 53 54DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) : 55 AbstractMemory(p), 56 port(name() + ".port", *this), 57 retryRdReq(false), retryWrReq(false), 58 rowHitFlag(false), busState(READ),
| 49#include "debug/Drain.hh" 50#include "mem/dram_ctrl.hh" 51#include "sim/system.hh" 52 53using namespace std; 54 55DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) : 56 AbstractMemory(p), 57 port(name() + ".port", *this), 58 retryRdReq(false), retryWrReq(false), 59 rowHitFlag(false), busState(READ),
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59 respondEvent(this), refreshEvent(this), 60 nextReqEvent(this), drainManager(NULL),
| 60 nextReqEvent(this), respondEvent(this), activateEvent(this), 61 prechargeEvent(this), refreshEvent(this), powerEvent(this), 62 drainManager(NULL),
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61 deviceBusWidth(p->device_bus_width), burstLength(p->burst_length), 62 deviceRowBufferSize(p->device_rowbuffer_size), 63 devicesPerRank(p->devices_per_rank), 64 burstSize((devicesPerRank * burstLength * deviceBusWidth) / 8), 65 rowBufferSize(devicesPerRank * deviceRowBufferSize), 66 columnsPerRowBuffer(rowBufferSize / burstSize), 67 ranksPerChannel(p->ranks_per_channel), 68 banksPerRank(p->banks_per_rank), channels(p->channels), rowsPerBank(0), 69 readBufferSize(p->read_buffer_size), 70 writeBufferSize(p->write_buffer_size), 71 writeHighThreshold(writeBufferSize * p->write_high_thresh_perc / 100.0), 72 writeLowThreshold(writeBufferSize * p->write_low_thresh_perc / 100.0), 73 minWritesPerSwitch(p->min_writes_per_switch), 74 writesThisTime(0), readsThisTime(0), 75 tWTR(p->tWTR), tRTW(p->tRTW), tBURST(p->tBURST), 76 tRCD(p->tRCD), tCL(p->tCL), tRP(p->tRP), tRAS(p->tRAS), 77 tRFC(p->tRFC), tREFI(p->tREFI), tRRD(p->tRRD), 78 tXAW(p->tXAW), activationLimit(p->activation_limit), 79 memSchedPolicy(p->mem_sched_policy), addrMapping(p->addr_mapping), 80 pageMgmt(p->page_policy), 81 maxAccessesPerRow(p->max_accesses_per_row), 82 frontendLatency(p->static_frontend_latency), 83 backendLatency(p->static_backend_latency),
| 63 deviceBusWidth(p->device_bus_width), burstLength(p->burst_length), 64 deviceRowBufferSize(p->device_rowbuffer_size), 65 devicesPerRank(p->devices_per_rank), 66 burstSize((devicesPerRank * burstLength * deviceBusWidth) / 8), 67 rowBufferSize(devicesPerRank * deviceRowBufferSize), 68 columnsPerRowBuffer(rowBufferSize / burstSize), 69 ranksPerChannel(p->ranks_per_channel), 70 banksPerRank(p->banks_per_rank), channels(p->channels), rowsPerBank(0), 71 readBufferSize(p->read_buffer_size), 72 writeBufferSize(p->write_buffer_size), 73 writeHighThreshold(writeBufferSize * p->write_high_thresh_perc / 100.0), 74 writeLowThreshold(writeBufferSize * p->write_low_thresh_perc / 100.0), 75 minWritesPerSwitch(p->min_writes_per_switch), 76 writesThisTime(0), readsThisTime(0), 77 tWTR(p->tWTR), tRTW(p->tRTW), tBURST(p->tBURST), 78 tRCD(p->tRCD), tCL(p->tCL), tRP(p->tRP), tRAS(p->tRAS), 79 tRFC(p->tRFC), tREFI(p->tREFI), tRRD(p->tRRD), 80 tXAW(p->tXAW), activationLimit(p->activation_limit), 81 memSchedPolicy(p->mem_sched_policy), addrMapping(p->addr_mapping), 82 pageMgmt(p->page_policy), 83 maxAccessesPerRow(p->max_accesses_per_row), 84 frontendLatency(p->static_frontend_latency), 85 backendLatency(p->static_backend_latency),
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84 busBusyUntil(0), refreshDueAt(0), refreshState(REF_IDLE), prevArrival(0), 85 nextReqTime(0), idleStartTick(0), numBanksActive(0)
| 86 busBusyUntil(0), refreshDueAt(0), refreshState(REF_IDLE), 87 pwrStateTrans(PWR_IDLE), pwrState(PWR_IDLE), prevArrival(0), 88 nextReqTime(0), pwrStateTick(0), numBanksActive(0)
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86{ 87 // create the bank states based on the dimensions of the ranks and 88 // banks 89 banks.resize(ranksPerChannel); 90 actTicks.resize(ranksPerChannel); 91 for (size_t c = 0; c < ranksPerChannel; ++c) { 92 banks[c].resize(banksPerRank); 93 actTicks[c].resize(activationLimit, 0); 94 } 95 96 // perform a basic check of the write thresholds 97 if (p->write_low_thresh_perc >= p->write_high_thresh_perc) 98 fatal("Write buffer low threshold %d must be smaller than the " 99 "high threshold %d\n", p->write_low_thresh_perc, 100 p->write_high_thresh_perc); 101 102 // determine the rows per bank by looking at the total capacity 103 uint64_t capacity = ULL(1) << ceilLog2(AbstractMemory::size()); 104 105 DPRINTF(DRAM, "Memory capacity %lld (%lld) bytes\n", capacity, 106 AbstractMemory::size()); 107 108 DPRINTF(DRAM, "Row buffer size %d bytes with %d columns per row buffer\n", 109 rowBufferSize, columnsPerRowBuffer); 110 111 rowsPerBank = capacity / (rowBufferSize * banksPerRank * ranksPerChannel); 112 113 if (range.interleaved()) { 114 if (channels != range.stripes()) 115 fatal("%s has %d interleaved address stripes but %d channel(s)\n", 116 name(), range.stripes(), channels); 117 118 if (addrMapping == Enums::RoRaBaChCo) { 119 if (rowBufferSize != range.granularity()) { 120 fatal("Interleaving of %s doesn't match RoRaBaChCo " 121 "address map\n", name()); 122 } 123 } else if (addrMapping == Enums::RoRaBaCoCh) { 124 if (system()->cacheLineSize() != range.granularity()) { 125 fatal("Interleaving of %s doesn't match RoRaBaCoCh " 126 "address map\n", name()); 127 } 128 } else if (addrMapping == Enums::RoCoRaBaCh) { 129 if (system()->cacheLineSize() != range.granularity()) 130 fatal("Interleaving of %s doesn't match RoCoRaBaCh " 131 "address map\n", name()); 132 } 133 } 134 135 // some basic sanity checks 136 if (tREFI <= tRP || tREFI <= tRFC) { 137 fatal("tREFI (%d) must be larger than tRP (%d) and tRFC (%d)\n", 138 tREFI, tRP, tRFC); 139 } 140} 141 142void 143DRAMCtrl::init() 144{ 145 if (!port.isConnected()) { 146 fatal("DRAMCtrl %s is unconnected!\n", name()); 147 } else { 148 port.sendRangeChange(); 149 } 150} 151 152void 153DRAMCtrl::startup() 154{ 155 // update the start tick for the precharge accounting to the 156 // current tick
| 89{ 90 // create the bank states based on the dimensions of the ranks and 91 // banks 92 banks.resize(ranksPerChannel); 93 actTicks.resize(ranksPerChannel); 94 for (size_t c = 0; c < ranksPerChannel; ++c) { 95 banks[c].resize(banksPerRank); 96 actTicks[c].resize(activationLimit, 0); 97 } 98 99 // perform a basic check of the write thresholds 100 if (p->write_low_thresh_perc >= p->write_high_thresh_perc) 101 fatal("Write buffer low threshold %d must be smaller than the " 102 "high threshold %d\n", p->write_low_thresh_perc, 103 p->write_high_thresh_perc); 104 105 // determine the rows per bank by looking at the total capacity 106 uint64_t capacity = ULL(1) << ceilLog2(AbstractMemory::size()); 107 108 DPRINTF(DRAM, "Memory capacity %lld (%lld) bytes\n", capacity, 109 AbstractMemory::size()); 110 111 DPRINTF(DRAM, "Row buffer size %d bytes with %d columns per row buffer\n", 112 rowBufferSize, columnsPerRowBuffer); 113 114 rowsPerBank = capacity / (rowBufferSize * banksPerRank * ranksPerChannel); 115 116 if (range.interleaved()) { 117 if (channels != range.stripes()) 118 fatal("%s has %d interleaved address stripes but %d channel(s)\n", 119 name(), range.stripes(), channels); 120 121 if (addrMapping == Enums::RoRaBaChCo) { 122 if (rowBufferSize != range.granularity()) { 123 fatal("Interleaving of %s doesn't match RoRaBaChCo " 124 "address map\n", name()); 125 } 126 } else if (addrMapping == Enums::RoRaBaCoCh) { 127 if (system()->cacheLineSize() != range.granularity()) { 128 fatal("Interleaving of %s doesn't match RoRaBaCoCh " 129 "address map\n", name()); 130 } 131 } else if (addrMapping == Enums::RoCoRaBaCh) { 132 if (system()->cacheLineSize() != range.granularity()) 133 fatal("Interleaving of %s doesn't match RoCoRaBaCh " 134 "address map\n", name()); 135 } 136 } 137 138 // some basic sanity checks 139 if (tREFI <= tRP || tREFI <= tRFC) { 140 fatal("tREFI (%d) must be larger than tRP (%d) and tRFC (%d)\n", 141 tREFI, tRP, tRFC); 142 } 143} 144 145void 146DRAMCtrl::init() 147{ 148 if (!port.isConnected()) { 149 fatal("DRAMCtrl %s is unconnected!\n", name()); 150 } else { 151 port.sendRangeChange(); 152 } 153} 154 155void 156DRAMCtrl::startup() 157{ 158 // update the start tick for the precharge accounting to the 159 // current tick
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157 idleStartTick = curTick();
| 160 pwrStateTick = curTick();
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158 159 // shift the bus busy time sufficiently far ahead that we never 160 // have to worry about negative values when computing the time for 161 // the next request, this will add an insignificant bubble at the 162 // start of simulation 163 busBusyUntil = curTick() + tRP + tRCD + tCL; 164 165 // print the configuration of the controller 166 printParams(); 167 168 // kick off the refresh, and give ourselves enough time to 169 // precharge 170 schedule(refreshEvent, curTick() + tREFI - tRP); 171} 172 173Tick 174DRAMCtrl::recvAtomic(PacketPtr pkt) 175{ 176 DPRINTF(DRAM, "recvAtomic: %s 0x%x\n", pkt->cmdString(), pkt->getAddr()); 177 178 // do the actual memory access and turn the packet into a response 179 access(pkt); 180 181 Tick latency = 0; 182 if (!pkt->memInhibitAsserted() && pkt->hasData()) { 183 // this value is not supposed to be accurate, just enough to 184 // keep things going, mimic a closed page 185 latency = tRP + tRCD + tCL; 186 } 187 return latency; 188} 189 190bool 191DRAMCtrl::readQueueFull(unsigned int neededEntries) const 192{ 193 DPRINTF(DRAM, "Read queue limit %d, current size %d, entries needed %d\n", 194 readBufferSize, readQueue.size() + respQueue.size(), 195 neededEntries); 196 197 return 198 (readQueue.size() + respQueue.size() + neededEntries) > readBufferSize; 199} 200 201bool 202DRAMCtrl::writeQueueFull(unsigned int neededEntries) const 203{ 204 DPRINTF(DRAM, "Write queue limit %d, current size %d, entries needed %d\n", 205 writeBufferSize, writeQueue.size(), neededEntries); 206 return (writeQueue.size() + neededEntries) > writeBufferSize; 207} 208 209DRAMCtrl::DRAMPacket* 210DRAMCtrl::decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned size, 211 bool isRead) 212{ 213 // decode the address based on the address mapping scheme, with 214 // Ro, Ra, Co, Ba and Ch denoting row, rank, column, bank and 215 // channel, respectively 216 uint8_t rank; 217 uint8_t bank; 218 uint16_t row; 219 220 // truncate the address to the access granularity 221 Addr addr = dramPktAddr / burstSize; 222 223 // we have removed the lowest order address bits that denote the 224 // position within the column 225 if (addrMapping == Enums::RoRaBaChCo) { 226 // the lowest order bits denote the column to ensure that 227 // sequential cache lines occupy the same row 228 addr = addr / columnsPerRowBuffer; 229 230 // take out the channel part of the address 231 addr = addr / channels; 232 233 // after the channel bits, get the bank bits to interleave 234 // over the banks 235 bank = addr % banksPerRank; 236 addr = addr / banksPerRank; 237 238 // after the bank, we get the rank bits which thus interleaves 239 // over the ranks 240 rank = addr % ranksPerChannel; 241 addr = addr / ranksPerChannel; 242 243 // lastly, get the row bits 244 row = addr % rowsPerBank; 245 addr = addr / rowsPerBank; 246 } else if (addrMapping == Enums::RoRaBaCoCh) { 247 // take out the channel part of the address 248 addr = addr / channels; 249 250 // next, the column 251 addr = addr / columnsPerRowBuffer; 252 253 // after the column bits, we get the bank bits to interleave 254 // over the banks 255 bank = addr % banksPerRank; 256 addr = addr / banksPerRank; 257 258 // after the bank, we get the rank bits which thus interleaves 259 // over the ranks 260 rank = addr % ranksPerChannel; 261 addr = addr / ranksPerChannel; 262 263 // lastly, get the row bits 264 row = addr % rowsPerBank; 265 addr = addr / rowsPerBank; 266 } else if (addrMapping == Enums::RoCoRaBaCh) { 267 // optimise for closed page mode and utilise maximum 268 // parallelism of the DRAM (at the cost of power) 269 270 // take out the channel part of the address, not that this has 271 // to match with how accesses are interleaved between the 272 // controllers in the address mapping 273 addr = addr / channels; 274 275 // start with the bank bits, as this provides the maximum 276 // opportunity for parallelism between requests 277 bank = addr % banksPerRank; 278 addr = addr / banksPerRank; 279 280 // next get the rank bits 281 rank = addr % ranksPerChannel; 282 addr = addr / ranksPerChannel; 283 284 // next the column bits which we do not need to keep track of 285 // and simply skip past 286 addr = addr / columnsPerRowBuffer; 287 288 // lastly, get the row bits 289 row = addr % rowsPerBank; 290 addr = addr / rowsPerBank; 291 } else 292 panic("Unknown address mapping policy chosen!"); 293 294 assert(rank < ranksPerChannel); 295 assert(bank < banksPerRank); 296 assert(row < rowsPerBank); 297 298 DPRINTF(DRAM, "Address: %lld Rank %d Bank %d Row %d\n", 299 dramPktAddr, rank, bank, row); 300 301 // create the corresponding DRAM packet with the entry time and 302 // ready time set to the current tick, the latter will be updated 303 // later 304 uint16_t bank_id = banksPerRank * rank + bank; 305 return new DRAMPacket(pkt, isRead, rank, bank, row, bank_id, dramPktAddr, 306 size, banks[rank][bank]); 307} 308 309void 310DRAMCtrl::addToReadQueue(PacketPtr pkt, unsigned int pktCount) 311{ 312 // only add to the read queue here. whenever the request is 313 // eventually done, set the readyTime, and call schedule() 314 assert(!pkt->isWrite()); 315 316 assert(pktCount != 0); 317 318 // if the request size is larger than burst size, the pkt is split into 319 // multiple DRAM packets 320 // Note if the pkt starting address is not aligened to burst size, the 321 // address of first DRAM packet is kept unaliged. Subsequent DRAM packets 322 // are aligned to burst size boundaries. This is to ensure we accurately 323 // check read packets against packets in write queue. 324 Addr addr = pkt->getAddr(); 325 unsigned pktsServicedByWrQ = 0; 326 BurstHelper* burst_helper = NULL; 327 for (int cnt = 0; cnt < pktCount; ++cnt) { 328 unsigned size = std::min((addr | (burstSize - 1)) + 1, 329 pkt->getAddr() + pkt->getSize()) - addr; 330 readPktSize[ceilLog2(size)]++; 331 readBursts++; 332 333 // First check write buffer to see if the data is already at 334 // the controller 335 bool foundInWrQ = false; 336 for (auto i = writeQueue.begin(); i != writeQueue.end(); ++i) { 337 // check if the read is subsumed in the write entry we are 338 // looking at 339 if ((*i)->addr <= addr && 340 (addr + size) <= ((*i)->addr + (*i)->size)) { 341 foundInWrQ = true; 342 servicedByWrQ++; 343 pktsServicedByWrQ++; 344 DPRINTF(DRAM, "Read to addr %lld with size %d serviced by " 345 "write queue\n", addr, size); 346 bytesReadWrQ += burstSize; 347 break; 348 } 349 } 350 351 // If not found in the write q, make a DRAM packet and 352 // push it onto the read queue 353 if (!foundInWrQ) { 354 355 // Make the burst helper for split packets 356 if (pktCount > 1 && burst_helper == NULL) { 357 DPRINTF(DRAM, "Read to addr %lld translates to %d " 358 "dram requests\n", pkt->getAddr(), pktCount); 359 burst_helper = new BurstHelper(pktCount); 360 } 361 362 DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, true); 363 dram_pkt->burstHelper = burst_helper; 364 365 assert(!readQueueFull(1)); 366 rdQLenPdf[readQueue.size() + respQueue.size()]++; 367 368 DPRINTF(DRAM, "Adding to read queue\n"); 369 370 readQueue.push_back(dram_pkt); 371 372 // Update stats 373 avgRdQLen = readQueue.size() + respQueue.size(); 374 } 375 376 // Starting address of next dram pkt (aligend to burstSize boundary) 377 addr = (addr | (burstSize - 1)) + 1; 378 } 379 380 // If all packets are serviced by write queue, we send the repsonse back 381 if (pktsServicedByWrQ == pktCount) { 382 accessAndRespond(pkt, frontendLatency); 383 return; 384 } 385 386 // Update how many split packets are serviced by write queue 387 if (burst_helper != NULL) 388 burst_helper->burstsServiced = pktsServicedByWrQ; 389 390 // If we are not already scheduled to get a request out of the 391 // queue, do so now 392 if (!nextReqEvent.scheduled()) { 393 DPRINTF(DRAM, "Request scheduled immediately\n"); 394 schedule(nextReqEvent, curTick()); 395 } 396} 397 398void 399DRAMCtrl::addToWriteQueue(PacketPtr pkt, unsigned int pktCount) 400{ 401 // only add to the write queue here. whenever the request is 402 // eventually done, set the readyTime, and call schedule() 403 assert(pkt->isWrite()); 404 405 // if the request size is larger than burst size, the pkt is split into 406 // multiple DRAM packets 407 Addr addr = pkt->getAddr(); 408 for (int cnt = 0; cnt < pktCount; ++cnt) { 409 unsigned size = std::min((addr | (burstSize - 1)) + 1, 410 pkt->getAddr() + pkt->getSize()) - addr; 411 writePktSize[ceilLog2(size)]++; 412 writeBursts++; 413 414 // see if we can merge with an existing item in the write 415 // queue and keep track of whether we have merged or not so we 416 // can stop at that point and also avoid enqueueing a new 417 // request 418 bool merged = false; 419 auto w = writeQueue.begin(); 420 421 while(!merged && w != writeQueue.end()) { 422 // either of the two could be first, if they are the same 423 // it does not matter which way we go 424 if ((*w)->addr >= addr) { 425 // the existing one starts after the new one, figure 426 // out where the new one ends with respect to the 427 // existing one 428 if ((addr + size) >= ((*w)->addr + (*w)->size)) { 429 // check if the existing one is completely 430 // subsumed in the new one 431 DPRINTF(DRAM, "Merging write covering existing burst\n"); 432 merged = true; 433 // update both the address and the size 434 (*w)->addr = addr; 435 (*w)->size = size; 436 } else if ((addr + size) >= (*w)->addr && 437 ((*w)->addr + (*w)->size - addr) <= burstSize) { 438 // the new one is just before or partially 439 // overlapping with the existing one, and together 440 // they fit within a burst 441 DPRINTF(DRAM, "Merging write before existing burst\n"); 442 merged = true; 443 // the existing queue item needs to be adjusted with 444 // respect to both address and size 445 (*w)->size = (*w)->addr + (*w)->size - addr; 446 (*w)->addr = addr; 447 } 448 } else { 449 // the new one starts after the current one, figure 450 // out where the existing one ends with respect to the 451 // new one 452 if (((*w)->addr + (*w)->size) >= (addr + size)) { 453 // check if the new one is completely subsumed in the 454 // existing one 455 DPRINTF(DRAM, "Merging write into existing burst\n"); 456 merged = true; 457 // no adjustments necessary 458 } else if (((*w)->addr + (*w)->size) >= addr && 459 (addr + size - (*w)->addr) <= burstSize) { 460 // the existing one is just before or partially 461 // overlapping with the new one, and together 462 // they fit within a burst 463 DPRINTF(DRAM, "Merging write after existing burst\n"); 464 merged = true; 465 // the address is right, and only the size has 466 // to be adjusted 467 (*w)->size = addr + size - (*w)->addr; 468 } 469 } 470 ++w; 471 } 472 473 // if the item was not merged we need to create a new write 474 // and enqueue it 475 if (!merged) { 476 DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, false); 477 478 assert(writeQueue.size() < writeBufferSize); 479 wrQLenPdf[writeQueue.size()]++; 480 481 DPRINTF(DRAM, "Adding to write queue\n"); 482 483 writeQueue.push_back(dram_pkt); 484 485 // Update stats 486 avgWrQLen = writeQueue.size(); 487 } else { 488 // keep track of the fact that this burst effectively 489 // disappeared as it was merged with an existing one 490 mergedWrBursts++; 491 } 492 493 // Starting address of next dram pkt (aligend to burstSize boundary) 494 addr = (addr | (burstSize - 1)) + 1; 495 } 496 497 // we do not wait for the writes to be send to the actual memory, 498 // but instead take responsibility for the consistency here and 499 // snoop the write queue for any upcoming reads 500 // @todo, if a pkt size is larger than burst size, we might need a 501 // different front end latency 502 accessAndRespond(pkt, frontendLatency); 503 504 // If we are not already scheduled to get a request out of the 505 // queue, do so now 506 if (!nextReqEvent.scheduled()) { 507 DPRINTF(DRAM, "Request scheduled immediately\n"); 508 schedule(nextReqEvent, curTick()); 509 } 510} 511 512void 513DRAMCtrl::printParams() const 514{ 515 // Sanity check print of important parameters 516 DPRINTF(DRAM, 517 "Memory controller %s physical organization\n" \ 518 "Number of devices per rank %d\n" \ 519 "Device bus width (in bits) %d\n" \ 520 "DRAM data bus burst (bytes) %d\n" \ 521 "Row buffer size (bytes) %d\n" \ 522 "Columns per row buffer %d\n" \ 523 "Rows per bank %d\n" \ 524 "Banks per rank %d\n" \ 525 "Ranks per channel %d\n" \ 526 "Total mem capacity (bytes) %u\n", 527 name(), devicesPerRank, deviceBusWidth, burstSize, rowBufferSize, 528 columnsPerRowBuffer, rowsPerBank, banksPerRank, ranksPerChannel, 529 rowBufferSize * rowsPerBank * banksPerRank * ranksPerChannel); 530 531 string scheduler = memSchedPolicy == Enums::fcfs ? "FCFS" : "FR-FCFS"; 532 string address_mapping = addrMapping == Enums::RoRaBaChCo ? "RoRaBaChCo" : 533 (addrMapping == Enums::RoRaBaCoCh ? "RoRaBaCoCh" : "RoCoRaBaCh"); 534 string page_policy = pageMgmt == Enums::open ? "OPEN" : 535 (pageMgmt == Enums::open_adaptive ? "OPEN (adaptive)" : 536 (pageMgmt == Enums::close_adaptive ? "CLOSE (adaptive)" : "CLOSE")); 537 538 DPRINTF(DRAM, 539 "Memory controller %s characteristics\n" \ 540 "Read buffer size %d\n" \ 541 "Write buffer size %d\n" \ 542 "Write high thresh %d\n" \ 543 "Write low thresh %d\n" \ 544 "Scheduler %s\n" \ 545 "Address mapping %s\n" \ 546 "Page policy %s\n", 547 name(), readBufferSize, writeBufferSize, writeHighThreshold, 548 writeLowThreshold, scheduler, address_mapping, page_policy); 549 550 DPRINTF(DRAM, "Memory controller %s timing specs\n" \ 551 "tRCD %d ticks\n" \ 552 "tCL %d ticks\n" \ 553 "tRP %d ticks\n" \ 554 "tBURST %d ticks\n" \ 555 "tRFC %d ticks\n" \ 556 "tREFI %d ticks\n" \ 557 "tWTR %d ticks\n" \ 558 "tRTW %d ticks\n" \ 559 "tXAW (%d) %d ticks\n", 560 name(), tRCD, tCL, tRP, tBURST, tRFC, tREFI, tWTR, 561 tRTW, activationLimit, tXAW); 562} 563 564void 565DRAMCtrl::printQs() const { 566 DPRINTF(DRAM, "===READ QUEUE===\n\n"); 567 for (auto i = readQueue.begin() ; i != readQueue.end() ; ++i) { 568 DPRINTF(DRAM, "Read %lu\n", (*i)->addr); 569 } 570 DPRINTF(DRAM, "\n===RESP QUEUE===\n\n"); 571 for (auto i = respQueue.begin() ; i != respQueue.end() ; ++i) { 572 DPRINTF(DRAM, "Response %lu\n", (*i)->addr); 573 } 574 DPRINTF(DRAM, "\n===WRITE QUEUE===\n\n"); 575 for (auto i = writeQueue.begin() ; i != writeQueue.end() ; ++i) { 576 DPRINTF(DRAM, "Write %lu\n", (*i)->addr); 577 } 578} 579 580bool 581DRAMCtrl::recvTimingReq(PacketPtr pkt) 582{ 583 /// @todo temporary hack to deal with memory corruption issues until 584 /// 4-phase transactions are complete 585 for (int x = 0; x < pendingDelete.size(); x++) 586 delete pendingDelete[x]; 587 pendingDelete.clear(); 588 589 // This is where we enter from the outside world 590 DPRINTF(DRAM, "recvTimingReq: request %s addr %lld size %d\n", 591 pkt->cmdString(), pkt->getAddr(), pkt->getSize()); 592 593 // simply drop inhibited packets for now 594 if (pkt->memInhibitAsserted()) { 595 DPRINTF(DRAM, "Inhibited packet -- Dropping it now\n"); 596 pendingDelete.push_back(pkt); 597 return true; 598 } 599 600 // Calc avg gap between requests 601 if (prevArrival != 0) { 602 totGap += curTick() - prevArrival; 603 } 604 prevArrival = curTick(); 605 606 607 // Find out how many dram packets a pkt translates to 608 // If the burst size is equal or larger than the pkt size, then a pkt 609 // translates to only one dram packet. Otherwise, a pkt translates to 610 // multiple dram packets 611 unsigned size = pkt->getSize(); 612 unsigned offset = pkt->getAddr() & (burstSize - 1); 613 unsigned int dram_pkt_count = divCeil(offset + size, burstSize); 614 615 // check local buffers and do not accept if full 616 if (pkt->isRead()) { 617 assert(size != 0); 618 if (readQueueFull(dram_pkt_count)) { 619 DPRINTF(DRAM, "Read queue full, not accepting\n"); 620 // remember that we have to retry this port 621 retryRdReq = true; 622 numRdRetry++; 623 return false; 624 } else { 625 addToReadQueue(pkt, dram_pkt_count); 626 readReqs++; 627 bytesReadSys += size; 628 } 629 } else if (pkt->isWrite()) { 630 assert(size != 0); 631 if (writeQueueFull(dram_pkt_count)) { 632 DPRINTF(DRAM, "Write queue full, not accepting\n"); 633 // remember that we have to retry this port 634 retryWrReq = true; 635 numWrRetry++; 636 return false; 637 } else { 638 addToWriteQueue(pkt, dram_pkt_count); 639 writeReqs++; 640 bytesWrittenSys += size; 641 } 642 } else { 643 DPRINTF(DRAM,"Neither read nor write, ignore timing\n"); 644 neitherReadNorWrite++; 645 accessAndRespond(pkt, 1); 646 } 647 648 return true; 649} 650 651void 652DRAMCtrl::processRespondEvent() 653{ 654 DPRINTF(DRAM, 655 "processRespondEvent(): Some req has reached its readyTime\n"); 656 657 DRAMPacket* dram_pkt = respQueue.front(); 658 659 if (dram_pkt->burstHelper) { 660 // it is a split packet 661 dram_pkt->burstHelper->burstsServiced++; 662 if (dram_pkt->burstHelper->burstsServiced == 663 dram_pkt->burstHelper->burstCount) { 664 // we have now serviced all children packets of a system packet 665 // so we can now respond to the requester 666 // @todo we probably want to have a different front end and back 667 // end latency for split packets 668 accessAndRespond(dram_pkt->pkt, frontendLatency + backendLatency); 669 delete dram_pkt->burstHelper; 670 dram_pkt->burstHelper = NULL; 671 } 672 } else { 673 // it is not a split packet 674 accessAndRespond(dram_pkt->pkt, frontendLatency + backendLatency); 675 } 676 677 delete respQueue.front(); 678 respQueue.pop_front(); 679 680 if (!respQueue.empty()) { 681 assert(respQueue.front()->readyTime >= curTick()); 682 assert(!respondEvent.scheduled()); 683 schedule(respondEvent, respQueue.front()->readyTime); 684 } else { 685 // if there is nothing left in any queue, signal a drain 686 if (writeQueue.empty() && readQueue.empty() && 687 drainManager) { 688 drainManager->signalDrainDone(); 689 drainManager = NULL; 690 } 691 } 692 693 // We have made a location in the queue available at this point, 694 // so if there is a read that was forced to wait, retry now 695 if (retryRdReq) { 696 retryRdReq = false; 697 port.sendRetry(); 698 } 699} 700 701void 702DRAMCtrl::chooseNext(std::deque<DRAMPacket*>& queue) 703{ 704 // This method does the arbitration between requests. The chosen 705 // packet is simply moved to the head of the queue. The other 706 // methods know that this is the place to look. For example, with 707 // FCFS, this method does nothing 708 assert(!queue.empty()); 709 710 if (queue.size() == 1) { 711 DPRINTF(DRAM, "Single request, nothing to do\n"); 712 return; 713 } 714 715 if (memSchedPolicy == Enums::fcfs) { 716 // Do nothing, since the correct request is already head 717 } else if (memSchedPolicy == Enums::frfcfs) { 718 reorderQueue(queue); 719 } else 720 panic("No scheduling policy chosen\n"); 721} 722 723void 724DRAMCtrl::reorderQueue(std::deque<DRAMPacket*>& queue) 725{ 726 // Only determine this when needed 727 uint64_t earliest_banks = 0; 728 729 // Search for row hits first, if no row hit is found then schedule the 730 // packet to one of the earliest banks available 731 bool found_earliest_pkt = false; 732 auto selected_pkt_it = queue.begin(); 733 734 for (auto i = queue.begin(); i != queue.end() ; ++i) { 735 DRAMPacket* dram_pkt = *i; 736 const Bank& bank = dram_pkt->bankRef; 737 // Check if it is a row hit 738 if (bank.openRow == dram_pkt->row) { 739 DPRINTF(DRAM, "Row buffer hit\n"); 740 selected_pkt_it = i; 741 break; 742 } else if (!found_earliest_pkt) { 743 // No row hit, go for first ready 744 if (earliest_banks == 0) 745 earliest_banks = minBankFreeAt(queue); 746 747 // Bank is ready or is the first available bank 748 if (bank.freeAt <= curTick() || 749 bits(earliest_banks, dram_pkt->bankId, dram_pkt->bankId)) { 750 // Remember the packet to be scheduled to one of the earliest 751 // banks available 752 selected_pkt_it = i; 753 found_earliest_pkt = true; 754 } 755 } 756 } 757 758 DRAMPacket* selected_pkt = *selected_pkt_it; 759 queue.erase(selected_pkt_it); 760 queue.push_front(selected_pkt); 761} 762 763void 764DRAMCtrl::accessAndRespond(PacketPtr pkt, Tick static_latency) 765{ 766 DPRINTF(DRAM, "Responding to Address %lld.. ",pkt->getAddr()); 767 768 bool needsResponse = pkt->needsResponse(); 769 // do the actual memory access which also turns the packet into a 770 // response 771 access(pkt); 772 773 // turn packet around to go back to requester if response expected 774 if (needsResponse) { 775 // access already turned the packet into a response 776 assert(pkt->isResponse()); 777 778 // @todo someone should pay for this 779 pkt->busFirstWordDelay = pkt->busLastWordDelay = 0; 780 781 // queue the packet in the response queue to be sent out after 782 // the static latency has passed 783 port.schedTimingResp(pkt, curTick() + static_latency); 784 } else { 785 // @todo the packet is going to be deleted, and the DRAMPacket 786 // is still having a pointer to it 787 pendingDelete.push_back(pkt); 788 } 789 790 DPRINTF(DRAM, "Done\n"); 791 792 return; 793} 794 795pair<Tick, Tick> 796DRAMCtrl::estimateLatency(DRAMPacket* dram_pkt, Tick inTime) 797{ 798 // If a request reaches a bank at tick 'inTime', how much time 799 // *after* that does it take to finish the request, depending 800 // on bank status and page open policy. Note that this method 801 // considers only the time taken for the actual read or write 802 // to complete, NOT any additional time thereafter for tRAS or 803 // tRP. 804 Tick accLat = 0; 805 Tick bankLat = 0; 806 rowHitFlag = false; 807 Tick potentialActTick; 808 809 const Bank& bank = dram_pkt->bankRef; 810 // open-page policy or close_adaptive policy 811 if (pageMgmt == Enums::open || pageMgmt == Enums::open_adaptive || 812 pageMgmt == Enums::close_adaptive) { 813 if (bank.openRow == dram_pkt->row) { 814 // When we have a row-buffer hit, 815 // we don't care about tRAS having expired or not, 816 // but do care about bank being free for access 817 rowHitFlag = true; 818 819 // When a series of requests arrive to the same row, 820 // DDR systems are capable of streaming data continuously 821 // at maximum bandwidth (subject to tCCD). Here, we approximate 822 // this condition, and assume that if whenever a bank is already 823 // busy and a new request comes in, it can be completed with no 824 // penalty beyond waiting for the existing read to complete. 825 if (bank.freeAt > inTime) { 826 accLat += bank.freeAt - inTime; 827 bankLat += 0; 828 } else { 829 // CAS latency only 830 accLat += tCL; 831 bankLat += tCL; 832 } 833 834 } else { 835 // Row-buffer miss, need to close existing row 836 // once tRAS has expired, then open the new one, 837 // then add cas latency. 838 Tick freeTime = std::max(bank.tRASDoneAt, bank.freeAt); 839 840 if (freeTime > inTime) 841 accLat += freeTime - inTime; 842 843 // If the there is no open row (open adaptive), then there 844 // is no precharge delay, otherwise go with tRP 845 Tick precharge_delay = bank.openRow == Bank::NO_ROW ? 0 : tRP; 846 847 //The bank is free, and you may be able to activate 848 potentialActTick = inTime + accLat + precharge_delay; 849 if (potentialActTick < bank.actAllowedAt) 850 accLat += bank.actAllowedAt - potentialActTick; 851 852 accLat += precharge_delay + tRCD + tCL; 853 bankLat += precharge_delay + tRCD + tCL; 854 } 855 } else if (pageMgmt == Enums::close) { 856 // With a close page policy, no notion of 857 // bank.tRASDoneAt 858 if (bank.freeAt > inTime) 859 accLat += bank.freeAt - inTime; 860 861 //The bank is free, and you may be able to activate 862 potentialActTick = inTime + accLat; 863 if (potentialActTick < bank.actAllowedAt) 864 accLat += bank.actAllowedAt - potentialActTick; 865 866 // page already closed, simply open the row, and 867 // add cas latency 868 accLat += tRCD + tCL; 869 bankLat += tRCD + tCL; 870 } else 871 panic("No page management policy chosen\n"); 872 873 DPRINTF(DRAM, "Returning < %lld, %lld > from estimateLatency()\n", 874 bankLat, accLat); 875 876 return make_pair(bankLat, accLat); 877} 878 879void 880DRAMCtrl::recordActivate(Tick act_tick, uint8_t rank, uint8_t bank, 881 uint16_t row) 882{ 883 assert(0 <= rank && rank < ranksPerChannel); 884 assert(actTicks[rank].size() == activationLimit); 885 886 DPRINTF(DRAM, "Activate at tick %d\n", act_tick); 887
| 161 162 // shift the bus busy time sufficiently far ahead that we never 163 // have to worry about negative values when computing the time for 164 // the next request, this will add an insignificant bubble at the 165 // start of simulation 166 busBusyUntil = curTick() + tRP + tRCD + tCL; 167 168 // print the configuration of the controller 169 printParams(); 170 171 // kick off the refresh, and give ourselves enough time to 172 // precharge 173 schedule(refreshEvent, curTick() + tREFI - tRP); 174} 175 176Tick 177DRAMCtrl::recvAtomic(PacketPtr pkt) 178{ 179 DPRINTF(DRAM, "recvAtomic: %s 0x%x\n", pkt->cmdString(), pkt->getAddr()); 180 181 // do the actual memory access and turn the packet into a response 182 access(pkt); 183 184 Tick latency = 0; 185 if (!pkt->memInhibitAsserted() && pkt->hasData()) { 186 // this value is not supposed to be accurate, just enough to 187 // keep things going, mimic a closed page 188 latency = tRP + tRCD + tCL; 189 } 190 return latency; 191} 192 193bool 194DRAMCtrl::readQueueFull(unsigned int neededEntries) const 195{ 196 DPRINTF(DRAM, "Read queue limit %d, current size %d, entries needed %d\n", 197 readBufferSize, readQueue.size() + respQueue.size(), 198 neededEntries); 199 200 return 201 (readQueue.size() + respQueue.size() + neededEntries) > readBufferSize; 202} 203 204bool 205DRAMCtrl::writeQueueFull(unsigned int neededEntries) const 206{ 207 DPRINTF(DRAM, "Write queue limit %d, current size %d, entries needed %d\n", 208 writeBufferSize, writeQueue.size(), neededEntries); 209 return (writeQueue.size() + neededEntries) > writeBufferSize; 210} 211 212DRAMCtrl::DRAMPacket* 213DRAMCtrl::decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned size, 214 bool isRead) 215{ 216 // decode the address based on the address mapping scheme, with 217 // Ro, Ra, Co, Ba and Ch denoting row, rank, column, bank and 218 // channel, respectively 219 uint8_t rank; 220 uint8_t bank; 221 uint16_t row; 222 223 // truncate the address to the access granularity 224 Addr addr = dramPktAddr / burstSize; 225 226 // we have removed the lowest order address bits that denote the 227 // position within the column 228 if (addrMapping == Enums::RoRaBaChCo) { 229 // the lowest order bits denote the column to ensure that 230 // sequential cache lines occupy the same row 231 addr = addr / columnsPerRowBuffer; 232 233 // take out the channel part of the address 234 addr = addr / channels; 235 236 // after the channel bits, get the bank bits to interleave 237 // over the banks 238 bank = addr % banksPerRank; 239 addr = addr / banksPerRank; 240 241 // after the bank, we get the rank bits which thus interleaves 242 // over the ranks 243 rank = addr % ranksPerChannel; 244 addr = addr / ranksPerChannel; 245 246 // lastly, get the row bits 247 row = addr % rowsPerBank; 248 addr = addr / rowsPerBank; 249 } else if (addrMapping == Enums::RoRaBaCoCh) { 250 // take out the channel part of the address 251 addr = addr / channels; 252 253 // next, the column 254 addr = addr / columnsPerRowBuffer; 255 256 // after the column bits, we get the bank bits to interleave 257 // over the banks 258 bank = addr % banksPerRank; 259 addr = addr / banksPerRank; 260 261 // after the bank, we get the rank bits which thus interleaves 262 // over the ranks 263 rank = addr % ranksPerChannel; 264 addr = addr / ranksPerChannel; 265 266 // lastly, get the row bits 267 row = addr % rowsPerBank; 268 addr = addr / rowsPerBank; 269 } else if (addrMapping == Enums::RoCoRaBaCh) { 270 // optimise for closed page mode and utilise maximum 271 // parallelism of the DRAM (at the cost of power) 272 273 // take out the channel part of the address, not that this has 274 // to match with how accesses are interleaved between the 275 // controllers in the address mapping 276 addr = addr / channels; 277 278 // start with the bank bits, as this provides the maximum 279 // opportunity for parallelism between requests 280 bank = addr % banksPerRank; 281 addr = addr / banksPerRank; 282 283 // next get the rank bits 284 rank = addr % ranksPerChannel; 285 addr = addr / ranksPerChannel; 286 287 // next the column bits which we do not need to keep track of 288 // and simply skip past 289 addr = addr / columnsPerRowBuffer; 290 291 // lastly, get the row bits 292 row = addr % rowsPerBank; 293 addr = addr / rowsPerBank; 294 } else 295 panic("Unknown address mapping policy chosen!"); 296 297 assert(rank < ranksPerChannel); 298 assert(bank < banksPerRank); 299 assert(row < rowsPerBank); 300 301 DPRINTF(DRAM, "Address: %lld Rank %d Bank %d Row %d\n", 302 dramPktAddr, rank, bank, row); 303 304 // create the corresponding DRAM packet with the entry time and 305 // ready time set to the current tick, the latter will be updated 306 // later 307 uint16_t bank_id = banksPerRank * rank + bank; 308 return new DRAMPacket(pkt, isRead, rank, bank, row, bank_id, dramPktAddr, 309 size, banks[rank][bank]); 310} 311 312void 313DRAMCtrl::addToReadQueue(PacketPtr pkt, unsigned int pktCount) 314{ 315 // only add to the read queue here. whenever the request is 316 // eventually done, set the readyTime, and call schedule() 317 assert(!pkt->isWrite()); 318 319 assert(pktCount != 0); 320 321 // if the request size is larger than burst size, the pkt is split into 322 // multiple DRAM packets 323 // Note if the pkt starting address is not aligened to burst size, the 324 // address of first DRAM packet is kept unaliged. Subsequent DRAM packets 325 // are aligned to burst size boundaries. This is to ensure we accurately 326 // check read packets against packets in write queue. 327 Addr addr = pkt->getAddr(); 328 unsigned pktsServicedByWrQ = 0; 329 BurstHelper* burst_helper = NULL; 330 for (int cnt = 0; cnt < pktCount; ++cnt) { 331 unsigned size = std::min((addr | (burstSize - 1)) + 1, 332 pkt->getAddr() + pkt->getSize()) - addr; 333 readPktSize[ceilLog2(size)]++; 334 readBursts++; 335 336 // First check write buffer to see if the data is already at 337 // the controller 338 bool foundInWrQ = false; 339 for (auto i = writeQueue.begin(); i != writeQueue.end(); ++i) { 340 // check if the read is subsumed in the write entry we are 341 // looking at 342 if ((*i)->addr <= addr && 343 (addr + size) <= ((*i)->addr + (*i)->size)) { 344 foundInWrQ = true; 345 servicedByWrQ++; 346 pktsServicedByWrQ++; 347 DPRINTF(DRAM, "Read to addr %lld with size %d serviced by " 348 "write queue\n", addr, size); 349 bytesReadWrQ += burstSize; 350 break; 351 } 352 } 353 354 // If not found in the write q, make a DRAM packet and 355 // push it onto the read queue 356 if (!foundInWrQ) { 357 358 // Make the burst helper for split packets 359 if (pktCount > 1 && burst_helper == NULL) { 360 DPRINTF(DRAM, "Read to addr %lld translates to %d " 361 "dram requests\n", pkt->getAddr(), pktCount); 362 burst_helper = new BurstHelper(pktCount); 363 } 364 365 DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, true); 366 dram_pkt->burstHelper = burst_helper; 367 368 assert(!readQueueFull(1)); 369 rdQLenPdf[readQueue.size() + respQueue.size()]++; 370 371 DPRINTF(DRAM, "Adding to read queue\n"); 372 373 readQueue.push_back(dram_pkt); 374 375 // Update stats 376 avgRdQLen = readQueue.size() + respQueue.size(); 377 } 378 379 // Starting address of next dram pkt (aligend to burstSize boundary) 380 addr = (addr | (burstSize - 1)) + 1; 381 } 382 383 // If all packets are serviced by write queue, we send the repsonse back 384 if (pktsServicedByWrQ == pktCount) { 385 accessAndRespond(pkt, frontendLatency); 386 return; 387 } 388 389 // Update how many split packets are serviced by write queue 390 if (burst_helper != NULL) 391 burst_helper->burstsServiced = pktsServicedByWrQ; 392 393 // If we are not already scheduled to get a request out of the 394 // queue, do so now 395 if (!nextReqEvent.scheduled()) { 396 DPRINTF(DRAM, "Request scheduled immediately\n"); 397 schedule(nextReqEvent, curTick()); 398 } 399} 400 401void 402DRAMCtrl::addToWriteQueue(PacketPtr pkt, unsigned int pktCount) 403{ 404 // only add to the write queue here. whenever the request is 405 // eventually done, set the readyTime, and call schedule() 406 assert(pkt->isWrite()); 407 408 // if the request size is larger than burst size, the pkt is split into 409 // multiple DRAM packets 410 Addr addr = pkt->getAddr(); 411 for (int cnt = 0; cnt < pktCount; ++cnt) { 412 unsigned size = std::min((addr | (burstSize - 1)) + 1, 413 pkt->getAddr() + pkt->getSize()) - addr; 414 writePktSize[ceilLog2(size)]++; 415 writeBursts++; 416 417 // see if we can merge with an existing item in the write 418 // queue and keep track of whether we have merged or not so we 419 // can stop at that point and also avoid enqueueing a new 420 // request 421 bool merged = false; 422 auto w = writeQueue.begin(); 423 424 while(!merged && w != writeQueue.end()) { 425 // either of the two could be first, if they are the same 426 // it does not matter which way we go 427 if ((*w)->addr >= addr) { 428 // the existing one starts after the new one, figure 429 // out where the new one ends with respect to the 430 // existing one 431 if ((addr + size) >= ((*w)->addr + (*w)->size)) { 432 // check if the existing one is completely 433 // subsumed in the new one 434 DPRINTF(DRAM, "Merging write covering existing burst\n"); 435 merged = true; 436 // update both the address and the size 437 (*w)->addr = addr; 438 (*w)->size = size; 439 } else if ((addr + size) >= (*w)->addr && 440 ((*w)->addr + (*w)->size - addr) <= burstSize) { 441 // the new one is just before or partially 442 // overlapping with the existing one, and together 443 // they fit within a burst 444 DPRINTF(DRAM, "Merging write before existing burst\n"); 445 merged = true; 446 // the existing queue item needs to be adjusted with 447 // respect to both address and size 448 (*w)->size = (*w)->addr + (*w)->size - addr; 449 (*w)->addr = addr; 450 } 451 } else { 452 // the new one starts after the current one, figure 453 // out where the existing one ends with respect to the 454 // new one 455 if (((*w)->addr + (*w)->size) >= (addr + size)) { 456 // check if the new one is completely subsumed in the 457 // existing one 458 DPRINTF(DRAM, "Merging write into existing burst\n"); 459 merged = true; 460 // no adjustments necessary 461 } else if (((*w)->addr + (*w)->size) >= addr && 462 (addr + size - (*w)->addr) <= burstSize) { 463 // the existing one is just before or partially 464 // overlapping with the new one, and together 465 // they fit within a burst 466 DPRINTF(DRAM, "Merging write after existing burst\n"); 467 merged = true; 468 // the address is right, and only the size has 469 // to be adjusted 470 (*w)->size = addr + size - (*w)->addr; 471 } 472 } 473 ++w; 474 } 475 476 // if the item was not merged we need to create a new write 477 // and enqueue it 478 if (!merged) { 479 DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, false); 480 481 assert(writeQueue.size() < writeBufferSize); 482 wrQLenPdf[writeQueue.size()]++; 483 484 DPRINTF(DRAM, "Adding to write queue\n"); 485 486 writeQueue.push_back(dram_pkt); 487 488 // Update stats 489 avgWrQLen = writeQueue.size(); 490 } else { 491 // keep track of the fact that this burst effectively 492 // disappeared as it was merged with an existing one 493 mergedWrBursts++; 494 } 495 496 // Starting address of next dram pkt (aligend to burstSize boundary) 497 addr = (addr | (burstSize - 1)) + 1; 498 } 499 500 // we do not wait for the writes to be send to the actual memory, 501 // but instead take responsibility for the consistency here and 502 // snoop the write queue for any upcoming reads 503 // @todo, if a pkt size is larger than burst size, we might need a 504 // different front end latency 505 accessAndRespond(pkt, frontendLatency); 506 507 // If we are not already scheduled to get a request out of the 508 // queue, do so now 509 if (!nextReqEvent.scheduled()) { 510 DPRINTF(DRAM, "Request scheduled immediately\n"); 511 schedule(nextReqEvent, curTick()); 512 } 513} 514 515void 516DRAMCtrl::printParams() const 517{ 518 // Sanity check print of important parameters 519 DPRINTF(DRAM, 520 "Memory controller %s physical organization\n" \ 521 "Number of devices per rank %d\n" \ 522 "Device bus width (in bits) %d\n" \ 523 "DRAM data bus burst (bytes) %d\n" \ 524 "Row buffer size (bytes) %d\n" \ 525 "Columns per row buffer %d\n" \ 526 "Rows per bank %d\n" \ 527 "Banks per rank %d\n" \ 528 "Ranks per channel %d\n" \ 529 "Total mem capacity (bytes) %u\n", 530 name(), devicesPerRank, deviceBusWidth, burstSize, rowBufferSize, 531 columnsPerRowBuffer, rowsPerBank, banksPerRank, ranksPerChannel, 532 rowBufferSize * rowsPerBank * banksPerRank * ranksPerChannel); 533 534 string scheduler = memSchedPolicy == Enums::fcfs ? "FCFS" : "FR-FCFS"; 535 string address_mapping = addrMapping == Enums::RoRaBaChCo ? "RoRaBaChCo" : 536 (addrMapping == Enums::RoRaBaCoCh ? "RoRaBaCoCh" : "RoCoRaBaCh"); 537 string page_policy = pageMgmt == Enums::open ? "OPEN" : 538 (pageMgmt == Enums::open_adaptive ? "OPEN (adaptive)" : 539 (pageMgmt == Enums::close_adaptive ? "CLOSE (adaptive)" : "CLOSE")); 540 541 DPRINTF(DRAM, 542 "Memory controller %s characteristics\n" \ 543 "Read buffer size %d\n" \ 544 "Write buffer size %d\n" \ 545 "Write high thresh %d\n" \ 546 "Write low thresh %d\n" \ 547 "Scheduler %s\n" \ 548 "Address mapping %s\n" \ 549 "Page policy %s\n", 550 name(), readBufferSize, writeBufferSize, writeHighThreshold, 551 writeLowThreshold, scheduler, address_mapping, page_policy); 552 553 DPRINTF(DRAM, "Memory controller %s timing specs\n" \ 554 "tRCD %d ticks\n" \ 555 "tCL %d ticks\n" \ 556 "tRP %d ticks\n" \ 557 "tBURST %d ticks\n" \ 558 "tRFC %d ticks\n" \ 559 "tREFI %d ticks\n" \ 560 "tWTR %d ticks\n" \ 561 "tRTW %d ticks\n" \ 562 "tXAW (%d) %d ticks\n", 563 name(), tRCD, tCL, tRP, tBURST, tRFC, tREFI, tWTR, 564 tRTW, activationLimit, tXAW); 565} 566 567void 568DRAMCtrl::printQs() const { 569 DPRINTF(DRAM, "===READ QUEUE===\n\n"); 570 for (auto i = readQueue.begin() ; i != readQueue.end() ; ++i) { 571 DPRINTF(DRAM, "Read %lu\n", (*i)->addr); 572 } 573 DPRINTF(DRAM, "\n===RESP QUEUE===\n\n"); 574 for (auto i = respQueue.begin() ; i != respQueue.end() ; ++i) { 575 DPRINTF(DRAM, "Response %lu\n", (*i)->addr); 576 } 577 DPRINTF(DRAM, "\n===WRITE QUEUE===\n\n"); 578 for (auto i = writeQueue.begin() ; i != writeQueue.end() ; ++i) { 579 DPRINTF(DRAM, "Write %lu\n", (*i)->addr); 580 } 581} 582 583bool 584DRAMCtrl::recvTimingReq(PacketPtr pkt) 585{ 586 /// @todo temporary hack to deal with memory corruption issues until 587 /// 4-phase transactions are complete 588 for (int x = 0; x < pendingDelete.size(); x++) 589 delete pendingDelete[x]; 590 pendingDelete.clear(); 591 592 // This is where we enter from the outside world 593 DPRINTF(DRAM, "recvTimingReq: request %s addr %lld size %d\n", 594 pkt->cmdString(), pkt->getAddr(), pkt->getSize()); 595 596 // simply drop inhibited packets for now 597 if (pkt->memInhibitAsserted()) { 598 DPRINTF(DRAM, "Inhibited packet -- Dropping it now\n"); 599 pendingDelete.push_back(pkt); 600 return true; 601 } 602 603 // Calc avg gap between requests 604 if (prevArrival != 0) { 605 totGap += curTick() - prevArrival; 606 } 607 prevArrival = curTick(); 608 609 610 // Find out how many dram packets a pkt translates to 611 // If the burst size is equal or larger than the pkt size, then a pkt 612 // translates to only one dram packet. Otherwise, a pkt translates to 613 // multiple dram packets 614 unsigned size = pkt->getSize(); 615 unsigned offset = pkt->getAddr() & (burstSize - 1); 616 unsigned int dram_pkt_count = divCeil(offset + size, burstSize); 617 618 // check local buffers and do not accept if full 619 if (pkt->isRead()) { 620 assert(size != 0); 621 if (readQueueFull(dram_pkt_count)) { 622 DPRINTF(DRAM, "Read queue full, not accepting\n"); 623 // remember that we have to retry this port 624 retryRdReq = true; 625 numRdRetry++; 626 return false; 627 } else { 628 addToReadQueue(pkt, dram_pkt_count); 629 readReqs++; 630 bytesReadSys += size; 631 } 632 } else if (pkt->isWrite()) { 633 assert(size != 0); 634 if (writeQueueFull(dram_pkt_count)) { 635 DPRINTF(DRAM, "Write queue full, not accepting\n"); 636 // remember that we have to retry this port 637 retryWrReq = true; 638 numWrRetry++; 639 return false; 640 } else { 641 addToWriteQueue(pkt, dram_pkt_count); 642 writeReqs++; 643 bytesWrittenSys += size; 644 } 645 } else { 646 DPRINTF(DRAM,"Neither read nor write, ignore timing\n"); 647 neitherReadNorWrite++; 648 accessAndRespond(pkt, 1); 649 } 650 651 return true; 652} 653 654void 655DRAMCtrl::processRespondEvent() 656{ 657 DPRINTF(DRAM, 658 "processRespondEvent(): Some req has reached its readyTime\n"); 659 660 DRAMPacket* dram_pkt = respQueue.front(); 661 662 if (dram_pkt->burstHelper) { 663 // it is a split packet 664 dram_pkt->burstHelper->burstsServiced++; 665 if (dram_pkt->burstHelper->burstsServiced == 666 dram_pkt->burstHelper->burstCount) { 667 // we have now serviced all children packets of a system packet 668 // so we can now respond to the requester 669 // @todo we probably want to have a different front end and back 670 // end latency for split packets 671 accessAndRespond(dram_pkt->pkt, frontendLatency + backendLatency); 672 delete dram_pkt->burstHelper; 673 dram_pkt->burstHelper = NULL; 674 } 675 } else { 676 // it is not a split packet 677 accessAndRespond(dram_pkt->pkt, frontendLatency + backendLatency); 678 } 679 680 delete respQueue.front(); 681 respQueue.pop_front(); 682 683 if (!respQueue.empty()) { 684 assert(respQueue.front()->readyTime >= curTick()); 685 assert(!respondEvent.scheduled()); 686 schedule(respondEvent, respQueue.front()->readyTime); 687 } else { 688 // if there is nothing left in any queue, signal a drain 689 if (writeQueue.empty() && readQueue.empty() && 690 drainManager) { 691 drainManager->signalDrainDone(); 692 drainManager = NULL; 693 } 694 } 695 696 // We have made a location in the queue available at this point, 697 // so if there is a read that was forced to wait, retry now 698 if (retryRdReq) { 699 retryRdReq = false; 700 port.sendRetry(); 701 } 702} 703 704void 705DRAMCtrl::chooseNext(std::deque<DRAMPacket*>& queue) 706{ 707 // This method does the arbitration between requests. The chosen 708 // packet is simply moved to the head of the queue. The other 709 // methods know that this is the place to look. For example, with 710 // FCFS, this method does nothing 711 assert(!queue.empty()); 712 713 if (queue.size() == 1) { 714 DPRINTF(DRAM, "Single request, nothing to do\n"); 715 return; 716 } 717 718 if (memSchedPolicy == Enums::fcfs) { 719 // Do nothing, since the correct request is already head 720 } else if (memSchedPolicy == Enums::frfcfs) { 721 reorderQueue(queue); 722 } else 723 panic("No scheduling policy chosen\n"); 724} 725 726void 727DRAMCtrl::reorderQueue(std::deque<DRAMPacket*>& queue) 728{ 729 // Only determine this when needed 730 uint64_t earliest_banks = 0; 731 732 // Search for row hits first, if no row hit is found then schedule the 733 // packet to one of the earliest banks available 734 bool found_earliest_pkt = false; 735 auto selected_pkt_it = queue.begin(); 736 737 for (auto i = queue.begin(); i != queue.end() ; ++i) { 738 DRAMPacket* dram_pkt = *i; 739 const Bank& bank = dram_pkt->bankRef; 740 // Check if it is a row hit 741 if (bank.openRow == dram_pkt->row) { 742 DPRINTF(DRAM, "Row buffer hit\n"); 743 selected_pkt_it = i; 744 break; 745 } else if (!found_earliest_pkt) { 746 // No row hit, go for first ready 747 if (earliest_banks == 0) 748 earliest_banks = minBankFreeAt(queue); 749 750 // Bank is ready or is the first available bank 751 if (bank.freeAt <= curTick() || 752 bits(earliest_banks, dram_pkt->bankId, dram_pkt->bankId)) { 753 // Remember the packet to be scheduled to one of the earliest 754 // banks available 755 selected_pkt_it = i; 756 found_earliest_pkt = true; 757 } 758 } 759 } 760 761 DRAMPacket* selected_pkt = *selected_pkt_it; 762 queue.erase(selected_pkt_it); 763 queue.push_front(selected_pkt); 764} 765 766void 767DRAMCtrl::accessAndRespond(PacketPtr pkt, Tick static_latency) 768{ 769 DPRINTF(DRAM, "Responding to Address %lld.. ",pkt->getAddr()); 770 771 bool needsResponse = pkt->needsResponse(); 772 // do the actual memory access which also turns the packet into a 773 // response 774 access(pkt); 775 776 // turn packet around to go back to requester if response expected 777 if (needsResponse) { 778 // access already turned the packet into a response 779 assert(pkt->isResponse()); 780 781 // @todo someone should pay for this 782 pkt->busFirstWordDelay = pkt->busLastWordDelay = 0; 783 784 // queue the packet in the response queue to be sent out after 785 // the static latency has passed 786 port.schedTimingResp(pkt, curTick() + static_latency); 787 } else { 788 // @todo the packet is going to be deleted, and the DRAMPacket 789 // is still having a pointer to it 790 pendingDelete.push_back(pkt); 791 } 792 793 DPRINTF(DRAM, "Done\n"); 794 795 return; 796} 797 798pair<Tick, Tick> 799DRAMCtrl::estimateLatency(DRAMPacket* dram_pkt, Tick inTime) 800{ 801 // If a request reaches a bank at tick 'inTime', how much time 802 // *after* that does it take to finish the request, depending 803 // on bank status and page open policy. Note that this method 804 // considers only the time taken for the actual read or write 805 // to complete, NOT any additional time thereafter for tRAS or 806 // tRP. 807 Tick accLat = 0; 808 Tick bankLat = 0; 809 rowHitFlag = false; 810 Tick potentialActTick; 811 812 const Bank& bank = dram_pkt->bankRef; 813 // open-page policy or close_adaptive policy 814 if (pageMgmt == Enums::open || pageMgmt == Enums::open_adaptive || 815 pageMgmt == Enums::close_adaptive) { 816 if (bank.openRow == dram_pkt->row) { 817 // When we have a row-buffer hit, 818 // we don't care about tRAS having expired or not, 819 // but do care about bank being free for access 820 rowHitFlag = true; 821 822 // When a series of requests arrive to the same row, 823 // DDR systems are capable of streaming data continuously 824 // at maximum bandwidth (subject to tCCD). Here, we approximate 825 // this condition, and assume that if whenever a bank is already 826 // busy and a new request comes in, it can be completed with no 827 // penalty beyond waiting for the existing read to complete. 828 if (bank.freeAt > inTime) { 829 accLat += bank.freeAt - inTime; 830 bankLat += 0; 831 } else { 832 // CAS latency only 833 accLat += tCL; 834 bankLat += tCL; 835 } 836 837 } else { 838 // Row-buffer miss, need to close existing row 839 // once tRAS has expired, then open the new one, 840 // then add cas latency. 841 Tick freeTime = std::max(bank.tRASDoneAt, bank.freeAt); 842 843 if (freeTime > inTime) 844 accLat += freeTime - inTime; 845 846 // If the there is no open row (open adaptive), then there 847 // is no precharge delay, otherwise go with tRP 848 Tick precharge_delay = bank.openRow == Bank::NO_ROW ? 0 : tRP; 849 850 //The bank is free, and you may be able to activate 851 potentialActTick = inTime + accLat + precharge_delay; 852 if (potentialActTick < bank.actAllowedAt) 853 accLat += bank.actAllowedAt - potentialActTick; 854 855 accLat += precharge_delay + tRCD + tCL; 856 bankLat += precharge_delay + tRCD + tCL; 857 } 858 } else if (pageMgmt == Enums::close) { 859 // With a close page policy, no notion of 860 // bank.tRASDoneAt 861 if (bank.freeAt > inTime) 862 accLat += bank.freeAt - inTime; 863 864 //The bank is free, and you may be able to activate 865 potentialActTick = inTime + accLat; 866 if (potentialActTick < bank.actAllowedAt) 867 accLat += bank.actAllowedAt - potentialActTick; 868 869 // page already closed, simply open the row, and 870 // add cas latency 871 accLat += tRCD + tCL; 872 bankLat += tRCD + tCL; 873 } else 874 panic("No page management policy chosen\n"); 875 876 DPRINTF(DRAM, "Returning < %lld, %lld > from estimateLatency()\n", 877 bankLat, accLat); 878 879 return make_pair(bankLat, accLat); 880} 881 882void 883DRAMCtrl::recordActivate(Tick act_tick, uint8_t rank, uint8_t bank, 884 uint16_t row) 885{ 886 assert(0 <= rank && rank < ranksPerChannel); 887 assert(actTicks[rank].size() == activationLimit); 888 889 DPRINTF(DRAM, "Activate at tick %d\n", act_tick); 890
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888 // idleStartTick is the tick when all the banks were 889 // precharged. Thus, the difference between act_tick and 890 // idleStartTick gives the time for which the DRAM is in an idle 891 // state with all banks precharged. Note that we may end up 892 // "changing history" by scheduling an activation before an 893 // already scheduled precharge, effectively canceling it out. 894 if (numBanksActive == 0 && act_tick > idleStartTick) { 895 prechargeAllTime += act_tick - idleStartTick; 896 } 897
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898 // update the open row 899 assert(banks[rank][bank].openRow == Bank::NO_ROW); 900 banks[rank][bank].openRow = row; 901 902 // start counting anew, this covers both the case when we 903 // auto-precharged, and when this access is forced to 904 // precharge 905 banks[rank][bank].bytesAccessed = 0; 906 banks[rank][bank].rowAccesses = 0; 907 908 ++numBanksActive; 909 assert(numBanksActive <= banksPerRank * ranksPerChannel); 910 911 DPRINTF(DRAM, "Activate bank at tick %lld, now got %d active\n", 912 act_tick, numBanksActive); 913 914 // start by enforcing tRRD 915 for(int i = 0; i < banksPerRank; i++) { 916 // next activate must not happen before tRRD 917 banks[rank][i].actAllowedAt = act_tick + tRRD; 918 }
| 891 // update the open row 892 assert(banks[rank][bank].openRow == Bank::NO_ROW); 893 banks[rank][bank].openRow = row; 894 895 // start counting anew, this covers both the case when we 896 // auto-precharged, and when this access is forced to 897 // precharge 898 banks[rank][bank].bytesAccessed = 0; 899 banks[rank][bank].rowAccesses = 0; 900 901 ++numBanksActive; 902 assert(numBanksActive <= banksPerRank * ranksPerChannel); 903 904 DPRINTF(DRAM, "Activate bank at tick %lld, now got %d active\n", 905 act_tick, numBanksActive); 906 907 // start by enforcing tRRD 908 for(int i = 0; i < banksPerRank; i++) { 909 // next activate must not happen before tRRD 910 banks[rank][i].actAllowedAt = act_tick + tRRD; 911 }
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| 912
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919 // tRC should be added to activation tick of the bank currently accessed, 920 // where tRC = tRAS + tRP, this is just for a check as actAllowedAt for same 921 // bank is already captured by bank.freeAt and bank.tRASDoneAt 922 banks[rank][bank].actAllowedAt = act_tick + tRAS + tRP; 923 924 // next, we deal with tXAW, if the activation limit is disabled 925 // then we are done 926 if (actTicks[rank].empty()) 927 return; 928 929 // sanity check 930 if (actTicks[rank].back() && (act_tick - actTicks[rank].back()) < tXAW) { 931 // @todo For now, stick with a warning 932 warn("Got %d activates in window %d (%d - %d) which is smaller " 933 "than %d\n", activationLimit, act_tick - actTicks[rank].back(), 934 act_tick, actTicks[rank].back(), tXAW); 935 } 936 937 // shift the times used for the book keeping, the last element 938 // (highest index) is the oldest one and hence the lowest value 939 actTicks[rank].pop_back(); 940 941 // record an new activation (in the future) 942 actTicks[rank].push_front(act_tick); 943 944 // cannot activate more than X times in time window tXAW, push the 945 // next one (the X + 1'st activate) to be tXAW away from the 946 // oldest in our window of X 947 if (actTicks[rank].back() && (act_tick - actTicks[rank].back()) < tXAW) { 948 DPRINTF(DRAM, "Enforcing tXAW with X = %d, next activate no earlier " 949 "than %d\n", activationLimit, actTicks[rank].back() + tXAW); 950 for(int j = 0; j < banksPerRank; j++) 951 // next activate must not happen before end of window 952 banks[rank][j].actAllowedAt = actTicks[rank].back() + tXAW; 953 }
| 913 // tRC should be added to activation tick of the bank currently accessed, 914 // where tRC = tRAS + tRP, this is just for a check as actAllowedAt for same 915 // bank is already captured by bank.freeAt and bank.tRASDoneAt 916 banks[rank][bank].actAllowedAt = act_tick + tRAS + tRP; 917 918 // next, we deal with tXAW, if the activation limit is disabled 919 // then we are done 920 if (actTicks[rank].empty()) 921 return; 922 923 // sanity check 924 if (actTicks[rank].back() && (act_tick - actTicks[rank].back()) < tXAW) { 925 // @todo For now, stick with a warning 926 warn("Got %d activates in window %d (%d - %d) which is smaller " 927 "than %d\n", activationLimit, act_tick - actTicks[rank].back(), 928 act_tick, actTicks[rank].back(), tXAW); 929 } 930 931 // shift the times used for the book keeping, the last element 932 // (highest index) is the oldest one and hence the lowest value 933 actTicks[rank].pop_back(); 934 935 // record an new activation (in the future) 936 actTicks[rank].push_front(act_tick); 937 938 // cannot activate more than X times in time window tXAW, push the 939 // next one (the X + 1'st activate) to be tXAW away from the 940 // oldest in our window of X 941 if (actTicks[rank].back() && (act_tick - actTicks[rank].back()) < tXAW) { 942 DPRINTF(DRAM, "Enforcing tXAW with X = %d, next activate no earlier " 943 "than %d\n", activationLimit, actTicks[rank].back() + tXAW); 944 for(int j = 0; j < banksPerRank; j++) 945 // next activate must not happen before end of window 946 banks[rank][j].actAllowedAt = actTicks[rank].back() + tXAW; 947 }
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| 948 949 // at the point when this activate takes place, make sure we 950 // transition to the active power state 951 if (!activateEvent.scheduled()) 952 schedule(activateEvent, act_tick); 953 else if (activateEvent.when() > act_tick) 954 // move it sooner in time 955 reschedule(activateEvent, act_tick);
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954} 955 956void
| 956} 957 958void
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| 959DRAMCtrl::processActivateEvent() 960{ 961 // we should transition to the active state as soon as any bank is active 962 if (pwrState != PWR_ACT) 963 // note that at this point numBanksActive could be back at 964 // zero again due to a precharge scheduled in the future 965 schedulePowerEvent(PWR_ACT, curTick()); 966} 967 968void
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957DRAMCtrl::prechargeBank(Bank& bank, Tick free_at) 958{ 959 // make sure the bank has an open row 960 assert(bank.openRow != Bank::NO_ROW); 961 962 // sample the bytes per activate here since we are closing 963 // the page 964 bytesPerActivate.sample(bank.bytesAccessed); 965 966 bank.openRow = Bank::NO_ROW; 967 968 bank.freeAt = free_at; 969 970 assert(numBanksActive != 0); 971 --numBanksActive; 972 973 DPRINTF(DRAM, "Precharged bank, done at tick %lld, now got %d active\n", 974 bank.freeAt, numBanksActive); 975
| 969DRAMCtrl::prechargeBank(Bank& bank, Tick free_at) 970{ 971 // make sure the bank has an open row 972 assert(bank.openRow != Bank::NO_ROW); 973 974 // sample the bytes per activate here since we are closing 975 // the page 976 bytesPerActivate.sample(bank.bytesAccessed); 977 978 bank.openRow = Bank::NO_ROW; 979 980 bank.freeAt = free_at; 981 982 assert(numBanksActive != 0); 983 --numBanksActive; 984 985 DPRINTF(DRAM, "Precharged bank, done at tick %lld, now got %d active\n", 986 bank.freeAt, numBanksActive); 987
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| 988 // if we look at the current number of active banks we might be 989 // tempted to think the DRAM is now idle, however this can be 990 // undone by an activate that is scheduled to happen before we 991 // would have reached the idle state, so schedule an event and 992 // rather check once we actually make it to the point in time when 993 // the (last) precharge takes place 994 if (!prechargeEvent.scheduled()) 995 schedule(prechargeEvent, free_at); 996 else if (prechargeEvent.when() < free_at) 997 reschedule(prechargeEvent, free_at); 998} 999 1000void 1001DRAMCtrl::processPrechargeEvent() 1002{
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976 // if we reached zero, then special conditions apply as we track 977 // if all banks are precharged for the power models 978 if (numBanksActive == 0) {
| 1003 // if we reached zero, then special conditions apply as we track 1004 // if all banks are precharged for the power models 1005 if (numBanksActive == 0) {
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979 idleStartTick = std::max(idleStartTick, bank.freeAt); 980 DPRINTF(DRAM, "All banks precharged at tick: %ld\n", 981 idleStartTick);
| 1006 // we should transition to the idle state when the last bank 1007 // is precharged 1008 schedulePowerEvent(PWR_IDLE, curTick());
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982 } 983} 984 985void 986DRAMCtrl::doDRAMAccess(DRAMPacket* dram_pkt) 987{ 988 989 DPRINTF(DRAM, "Timing access to addr %lld, rank/bank/row %d %d %d\n", 990 dram_pkt->addr, dram_pkt->rank, dram_pkt->bank, dram_pkt->row); 991 992 // estimate the bank and access latency 993 pair<Tick, Tick> lat = estimateLatency(dram_pkt, curTick()); 994 Tick bankLat = lat.first; 995 Tick accessLat = lat.second; 996 Tick actTick; 997 998 // This request was woken up at this time based on a prior call 999 // to estimateLatency(). However, between then and now, both the 1000 // accessLatency and/or busBusyUntil may have changed. We need 1001 // to correct for that. 1002 1003 Tick addDelay = (curTick() + accessLat < busBusyUntil) ? 1004 busBusyUntil - (curTick() + accessLat) : 0; 1005 1006 Bank& bank = dram_pkt->bankRef; 1007 1008 // Update bank state 1009 if (pageMgmt == Enums::open || pageMgmt == Enums::open_adaptive || 1010 pageMgmt == Enums::close_adaptive) { 1011 1012 if (rowHitFlag) { 1013 bank.freeAt = curTick() + addDelay + accessLat; 1014 } else { 1015 // If there is a page open, precharge it. 1016 if (bank.openRow != Bank::NO_ROW) { 1017 prechargeBank(bank, std::max(std::max(bank.freeAt, 1018 bank.tRASDoneAt), 1019 curTick()) + tRP); 1020 } 1021 1022 // Any precharge is already part of the latency 1023 // estimation, so update the bank free time 1024 bank.freeAt = curTick() + addDelay + accessLat; 1025 1026 // any waiting for banks account for in freeAt 1027 actTick = bank.freeAt - tCL - tRCD; 1028 1029 // If you activated a new row do to this access, the next access 1030 // will have to respect tRAS for this bank 1031 bank.tRASDoneAt = actTick + tRAS; 1032 1033 recordActivate(actTick, dram_pkt->rank, dram_pkt->bank, 1034 dram_pkt->row); 1035 } 1036 1037 // increment the bytes accessed and the accesses per row 1038 bank.bytesAccessed += burstSize; 1039 ++bank.rowAccesses; 1040 1041 // if we reached the max, then issue with an auto-precharge 1042 bool auto_precharge = bank.rowAccesses == maxAccessesPerRow; 1043 1044 // if we did not hit the limit, we might still want to 1045 // auto-precharge 1046 if (!auto_precharge && 1047 (pageMgmt == Enums::open_adaptive || 1048 pageMgmt == Enums::close_adaptive)) { 1049 // a twist on the open and close page policies: 1050 // 1) open_adaptive page policy does not blindly keep the 1051 // page open, but close it if there are no row hits, and there 1052 // are bank conflicts in the queue 1053 // 2) close_adaptive page policy does not blindly close the 1054 // page, but closes it only if there are no row hits in the queue. 1055 // In this case, only force an auto precharge when there 1056 // are no same page hits in the queue 1057 bool got_more_hits = false; 1058 bool got_bank_conflict = false; 1059 1060 // either look at the read queue or write queue 1061 const deque<DRAMPacket*>& queue = dram_pkt->isRead ? readQueue : 1062 writeQueue; 1063 auto p = queue.begin(); 1064 // make sure we are not considering the packet that we are 1065 // currently dealing with (which is the head of the queue) 1066 ++p; 1067 1068 // keep on looking until we have found required condition or 1069 // reached the end 1070 while (!(got_more_hits && 1071 (got_bank_conflict || pageMgmt == Enums::close_adaptive)) && 1072 p != queue.end()) { 1073 bool same_rank_bank = (dram_pkt->rank == (*p)->rank) && 1074 (dram_pkt->bank == (*p)->bank); 1075 bool same_row = dram_pkt->row == (*p)->row; 1076 got_more_hits |= same_rank_bank && same_row; 1077 got_bank_conflict |= same_rank_bank && !same_row; 1078 ++p; 1079 } 1080 1081 // auto pre-charge when either 1082 // 1) open_adaptive policy, we have not got any more hits, and 1083 // have a bank conflict 1084 // 2) close_adaptive policy and we have not got any more hits 1085 auto_precharge = !got_more_hits && 1086 (got_bank_conflict || pageMgmt == Enums::close_adaptive); 1087 } 1088 1089 // if this access should use auto-precharge, then we are 1090 // closing the row 1091 if (auto_precharge) { 1092 prechargeBank(bank, std::max(bank.freeAt, bank.tRASDoneAt) + tRP); 1093 1094 DPRINTF(DRAM, "Auto-precharged bank: %d\n", dram_pkt->bankId); 1095 } 1096 1097 DPRINTF(DRAM, "doDRAMAccess::bank.freeAt is %lld\n", bank.freeAt); 1098 } else if (pageMgmt == Enums::close) { 1099 actTick = curTick() + addDelay + accessLat - tRCD - tCL; 1100 recordActivate(actTick, dram_pkt->rank, dram_pkt->bank, dram_pkt->row); 1101 1102 bank.freeAt = actTick + tRCD + tCL; 1103 bank.tRASDoneAt = actTick + tRAS; 1104 1105 // sample the relevant values when precharging 1106 bank.bytesAccessed = burstSize; 1107 bank.rowAccesses = 1; 1108 1109 prechargeBank(bank, std::max(bank.freeAt, bank.tRASDoneAt) + tRP); 1110 DPRINTF(DRAM, "doDRAMAccess::bank.freeAt is %lld\n", bank.freeAt); 1111 } else 1112 panic("No page management policy chosen\n"); 1113 1114 // Update request parameters 1115 dram_pkt->readyTime = curTick() + addDelay + accessLat + tBURST; 1116 1117 1118 DPRINTF(DRAM, "Req %lld: curtick is %lld accessLat is %d " \ 1119 "readytime is %lld busbusyuntil is %lld. " \ 1120 "Scheduling at readyTime\n", dram_pkt->addr, 1121 curTick(), accessLat, dram_pkt->readyTime, busBusyUntil); 1122 1123 // Make sure requests are not overlapping on the databus 1124 assert(dram_pkt->readyTime - busBusyUntil >= tBURST); 1125 1126 // Update bus state 1127 busBusyUntil = dram_pkt->readyTime; 1128 1129 DPRINTF(DRAM,"Access time is %lld\n", 1130 dram_pkt->readyTime - dram_pkt->entryTime); 1131 1132 // Update the minimum timing between the requests, this is a 1133 // conservative estimate of when we have to schedule the next 1134 // request to not introduce any unecessary bubbles. In most cases 1135 // we will wake up sooner than we have to. 1136 nextReqTime = busBusyUntil - (tRP + tRCD + tCL); 1137 1138 // Update the stats and schedule the next request 1139 if (dram_pkt->isRead) { 1140 ++readsThisTime; 1141 if (rowHitFlag) 1142 readRowHits++; 1143 bytesReadDRAM += burstSize; 1144 perBankRdBursts[dram_pkt->bankId]++; 1145 1146 // Update latency stats 1147 totMemAccLat += dram_pkt->readyTime - dram_pkt->entryTime; 1148 totBankLat += bankLat; 1149 totBusLat += tBURST; 1150 totQLat += dram_pkt->readyTime - dram_pkt->entryTime - bankLat - 1151 tBURST; 1152 } else { 1153 ++writesThisTime; 1154 if (rowHitFlag) 1155 writeRowHits++; 1156 bytesWritten += burstSize; 1157 perBankWrBursts[dram_pkt->bankId]++; 1158 } 1159} 1160 1161void 1162DRAMCtrl::moveToRespQ() 1163{ 1164 // Remove from read queue 1165 DRAMPacket* dram_pkt = readQueue.front(); 1166 readQueue.pop_front(); 1167 1168 // sanity check 1169 assert(dram_pkt->size <= burstSize); 1170 1171 // Insert into response queue sorted by readyTime 1172 // It will be sent back to the requestor at its 1173 // readyTime 1174 if (respQueue.empty()) { 1175 respQueue.push_front(dram_pkt); 1176 assert(!respondEvent.scheduled()); 1177 assert(dram_pkt->readyTime >= curTick()); 1178 schedule(respondEvent, dram_pkt->readyTime); 1179 } else { 1180 bool done = false; 1181 auto i = respQueue.begin(); 1182 while (!done && i != respQueue.end()) { 1183 if ((*i)->readyTime > dram_pkt->readyTime) { 1184 respQueue.insert(i, dram_pkt); 1185 done = true; 1186 } 1187 ++i; 1188 } 1189 1190 if (!done) 1191 respQueue.push_back(dram_pkt); 1192 1193 assert(respondEvent.scheduled()); 1194 1195 if (respQueue.front()->readyTime < respondEvent.when()) { 1196 assert(respQueue.front()->readyTime >= curTick()); 1197 reschedule(respondEvent, respQueue.front()->readyTime); 1198 } 1199 } 1200} 1201 1202void 1203DRAMCtrl::processNextReqEvent() 1204{ 1205 if (busState == READ_TO_WRITE) { 1206 DPRINTF(DRAM, "Switching to writes after %d reads with %d reads " 1207 "waiting\n", readsThisTime, readQueue.size()); 1208 1209 // sample and reset the read-related stats as we are now 1210 // transitioning to writes, and all reads are done 1211 rdPerTurnAround.sample(readsThisTime); 1212 readsThisTime = 0; 1213 1214 // now proceed to do the actual writes 1215 busState = WRITE; 1216 } else if (busState == WRITE_TO_READ) { 1217 DPRINTF(DRAM, "Switching to reads after %d writes with %d writes " 1218 "waiting\n", writesThisTime, writeQueue.size()); 1219 1220 wrPerTurnAround.sample(writesThisTime); 1221 writesThisTime = 0; 1222 1223 busState = READ; 1224 } 1225 1226 if (refreshState != REF_IDLE) { 1227 // if a refresh waiting for this event loop to finish, then hand 1228 // over now, and do not schedule a new nextReqEvent 1229 if (refreshState == REF_DRAIN) { 1230 DPRINTF(DRAM, "Refresh drain done, now precharging\n"); 1231 1232 refreshState = REF_PRE; 1233 1234 // hand control back to the refresh event loop 1235 schedule(refreshEvent, curTick()); 1236 } 1237 1238 // let the refresh finish before issuing any further requests 1239 return; 1240 } 1241 1242 // when we get here it is either a read or a write 1243 if (busState == READ) { 1244 1245 // track if we should switch or not 1246 bool switch_to_writes = false; 1247 1248 if (readQueue.empty()) { 1249 // In the case there is no read request to go next, 1250 // trigger writes if we have passed the low threshold (or 1251 // if we are draining) 1252 if (!writeQueue.empty() && 1253 (drainManager || writeQueue.size() > writeLowThreshold)) { 1254 1255 switch_to_writes = true; 1256 } else { 1257 // check if we are drained 1258 if (respQueue.empty () && drainManager) { 1259 drainManager->signalDrainDone(); 1260 drainManager = NULL; 1261 } 1262 1263 // nothing to do, not even any point in scheduling an 1264 // event for the next request 1265 return; 1266 } 1267 } else { 1268 // Figure out which read request goes next, and move it to the 1269 // front of the read queue 1270 chooseNext(readQueue); 1271 1272 doDRAMAccess(readQueue.front()); 1273 1274 // At this point we're done dealing with the request 1275 // It will be moved to a separate response queue with a 1276 // correct readyTime, and eventually be sent back at that 1277 // time 1278 moveToRespQ(); 1279 1280 // we have so many writes that we have to transition 1281 if (writeQueue.size() > writeHighThreshold) { 1282 switch_to_writes = true; 1283 } 1284 } 1285 1286 // switching to writes, either because the read queue is empty 1287 // and the writes have passed the low threshold (or we are 1288 // draining), or because the writes hit the hight threshold 1289 if (switch_to_writes) { 1290 // transition to writing 1291 busState = READ_TO_WRITE; 1292 1293 // add a bubble to the data bus, as defined by the 1294 // tRTW parameter 1295 busBusyUntil += tRTW; 1296 1297 // update the minimum timing between the requests, 1298 // this shifts us back in time far enough to do any 1299 // bank preparation 1300 nextReqTime = busBusyUntil - (tRP + tRCD + tCL); 1301 } 1302 } else { 1303 chooseNext(writeQueue); 1304 DRAMPacket* dram_pkt = writeQueue.front(); 1305 // sanity check 1306 assert(dram_pkt->size <= burstSize); 1307 doDRAMAccess(dram_pkt); 1308 1309 writeQueue.pop_front(); 1310 delete dram_pkt; 1311 1312 // If we emptied the write queue, or got sufficiently below the 1313 // threshold (using the minWritesPerSwitch as the hysteresis) and 1314 // are not draining, or we have reads waiting and have done enough 1315 // writes, then switch to reads. 1316 if (writeQueue.empty() || 1317 (writeQueue.size() + minWritesPerSwitch < writeLowThreshold && 1318 !drainManager) || 1319 (!readQueue.empty() && writesThisTime >= minWritesPerSwitch)) { 1320 // turn the bus back around for reads again 1321 busState = WRITE_TO_READ; 1322 1323 // note that the we switch back to reads also in the idle 1324 // case, which eventually will check for any draining and 1325 // also pause any further scheduling if there is really 1326 // nothing to do 1327 1328 // here we get a bit creative and shift the bus busy time not 1329 // just the tWTR, but also a CAS latency to capture the fact 1330 // that we are allowed to prepare a new bank, but not issue a 1331 // read command until after tWTR, in essence we capture a 1332 // bubble on the data bus that is tWTR + tCL 1333 busBusyUntil += tWTR + tCL; 1334 1335 // update the minimum timing between the requests, this shifts 1336 // us back in time far enough to do any bank preparation 1337 nextReqTime = busBusyUntil - (tRP + tRCD + tCL); 1338 } 1339 } 1340 1341 schedule(nextReqEvent, std::max(nextReqTime, curTick())); 1342 1343 // If there is space available and we have writes waiting then let 1344 // them retry. This is done here to ensure that the retry does not 1345 // cause a nextReqEvent to be scheduled before we do so as part of 1346 // the next request processing 1347 if (retryWrReq && writeQueue.size() < writeBufferSize) { 1348 retryWrReq = false; 1349 port.sendRetry(); 1350 } 1351} 1352 1353uint64_t 1354DRAMCtrl::minBankFreeAt(const deque<DRAMPacket*>& queue) const 1355{ 1356 uint64_t bank_mask = 0; 1357 Tick freeAt = MaxTick; 1358 1359 // detemrine if we have queued transactions targetting the 1360 // bank in question 1361 vector<bool> got_waiting(ranksPerChannel * banksPerRank, false); 1362 for (auto p = queue.begin(); p != queue.end(); ++p) { 1363 got_waiting[(*p)->bankId] = true; 1364 } 1365 1366 for (int i = 0; i < ranksPerChannel; i++) { 1367 for (int j = 0; j < banksPerRank; j++) { 1368 // if we have waiting requests for the bank, and it is 1369 // amongst the first available, update the mask 1370 if (got_waiting[i * banksPerRank + j] && 1371 banks[i][j].freeAt <= freeAt) { 1372 // reset bank mask if new minimum is found 1373 if (banks[i][j].freeAt < freeAt) 1374 bank_mask = 0; 1375 // set the bit corresponding to the available bank 1376 uint8_t bit_index = i * ranksPerChannel + j; 1377 replaceBits(bank_mask, bit_index, bit_index, 1); 1378 freeAt = banks[i][j].freeAt; 1379 } 1380 } 1381 } 1382 return bank_mask; 1383} 1384 1385void 1386DRAMCtrl::processRefreshEvent() 1387{ 1388 // when first preparing the refresh, remember when it was due 1389 if (refreshState == REF_IDLE) { 1390 // remember when the refresh is due 1391 refreshDueAt = curTick(); 1392 1393 // proceed to drain 1394 refreshState = REF_DRAIN; 1395 1396 DPRINTF(DRAM, "Refresh due\n"); 1397 } 1398 1399 // let any scheduled read or write go ahead, after which it will 1400 // hand control back to this event loop 1401 if (refreshState == REF_DRAIN) { 1402 if (nextReqEvent.scheduled()) { 1403 // hand control over to the request loop until it is 1404 // evaluated next 1405 DPRINTF(DRAM, "Refresh awaiting draining\n"); 1406 1407 return; 1408 } else { 1409 refreshState = REF_PRE; 1410 } 1411 } 1412 1413 // at this point, ensure that all banks are precharged 1414 if (refreshState == REF_PRE) {
| 1009 } 1010} 1011 1012void 1013DRAMCtrl::doDRAMAccess(DRAMPacket* dram_pkt) 1014{ 1015 1016 DPRINTF(DRAM, "Timing access to addr %lld, rank/bank/row %d %d %d\n", 1017 dram_pkt->addr, dram_pkt->rank, dram_pkt->bank, dram_pkt->row); 1018 1019 // estimate the bank and access latency 1020 pair<Tick, Tick> lat = estimateLatency(dram_pkt, curTick()); 1021 Tick bankLat = lat.first; 1022 Tick accessLat = lat.second; 1023 Tick actTick; 1024 1025 // This request was woken up at this time based on a prior call 1026 // to estimateLatency(). However, between then and now, both the 1027 // accessLatency and/or busBusyUntil may have changed. We need 1028 // to correct for that. 1029 1030 Tick addDelay = (curTick() + accessLat < busBusyUntil) ? 1031 busBusyUntil - (curTick() + accessLat) : 0; 1032 1033 Bank& bank = dram_pkt->bankRef; 1034 1035 // Update bank state 1036 if (pageMgmt == Enums::open || pageMgmt == Enums::open_adaptive || 1037 pageMgmt == Enums::close_adaptive) { 1038 1039 if (rowHitFlag) { 1040 bank.freeAt = curTick() + addDelay + accessLat; 1041 } else { 1042 // If there is a page open, precharge it. 1043 if (bank.openRow != Bank::NO_ROW) { 1044 prechargeBank(bank, std::max(std::max(bank.freeAt, 1045 bank.tRASDoneAt), 1046 curTick()) + tRP); 1047 } 1048 1049 // Any precharge is already part of the latency 1050 // estimation, so update the bank free time 1051 bank.freeAt = curTick() + addDelay + accessLat; 1052 1053 // any waiting for banks account for in freeAt 1054 actTick = bank.freeAt - tCL - tRCD; 1055 1056 // If you activated a new row do to this access, the next access 1057 // will have to respect tRAS for this bank 1058 bank.tRASDoneAt = actTick + tRAS; 1059 1060 recordActivate(actTick, dram_pkt->rank, dram_pkt->bank, 1061 dram_pkt->row); 1062 } 1063 1064 // increment the bytes accessed and the accesses per row 1065 bank.bytesAccessed += burstSize; 1066 ++bank.rowAccesses; 1067 1068 // if we reached the max, then issue with an auto-precharge 1069 bool auto_precharge = bank.rowAccesses == maxAccessesPerRow; 1070 1071 // if we did not hit the limit, we might still want to 1072 // auto-precharge 1073 if (!auto_precharge && 1074 (pageMgmt == Enums::open_adaptive || 1075 pageMgmt == Enums::close_adaptive)) { 1076 // a twist on the open and close page policies: 1077 // 1) open_adaptive page policy does not blindly keep the 1078 // page open, but close it if there are no row hits, and there 1079 // are bank conflicts in the queue 1080 // 2) close_adaptive page policy does not blindly close the 1081 // page, but closes it only if there are no row hits in the queue. 1082 // In this case, only force an auto precharge when there 1083 // are no same page hits in the queue 1084 bool got_more_hits = false; 1085 bool got_bank_conflict = false; 1086 1087 // either look at the read queue or write queue 1088 const deque<DRAMPacket*>& queue = dram_pkt->isRead ? readQueue : 1089 writeQueue; 1090 auto p = queue.begin(); 1091 // make sure we are not considering the packet that we are 1092 // currently dealing with (which is the head of the queue) 1093 ++p; 1094 1095 // keep on looking until we have found required condition or 1096 // reached the end 1097 while (!(got_more_hits && 1098 (got_bank_conflict || pageMgmt == Enums::close_adaptive)) && 1099 p != queue.end()) { 1100 bool same_rank_bank = (dram_pkt->rank == (*p)->rank) && 1101 (dram_pkt->bank == (*p)->bank); 1102 bool same_row = dram_pkt->row == (*p)->row; 1103 got_more_hits |= same_rank_bank && same_row; 1104 got_bank_conflict |= same_rank_bank && !same_row; 1105 ++p; 1106 } 1107 1108 // auto pre-charge when either 1109 // 1) open_adaptive policy, we have not got any more hits, and 1110 // have a bank conflict 1111 // 2) close_adaptive policy and we have not got any more hits 1112 auto_precharge = !got_more_hits && 1113 (got_bank_conflict || pageMgmt == Enums::close_adaptive); 1114 } 1115 1116 // if this access should use auto-precharge, then we are 1117 // closing the row 1118 if (auto_precharge) { 1119 prechargeBank(bank, std::max(bank.freeAt, bank.tRASDoneAt) + tRP); 1120 1121 DPRINTF(DRAM, "Auto-precharged bank: %d\n", dram_pkt->bankId); 1122 } 1123 1124 DPRINTF(DRAM, "doDRAMAccess::bank.freeAt is %lld\n", bank.freeAt); 1125 } else if (pageMgmt == Enums::close) { 1126 actTick = curTick() + addDelay + accessLat - tRCD - tCL; 1127 recordActivate(actTick, dram_pkt->rank, dram_pkt->bank, dram_pkt->row); 1128 1129 bank.freeAt = actTick + tRCD + tCL; 1130 bank.tRASDoneAt = actTick + tRAS; 1131 1132 // sample the relevant values when precharging 1133 bank.bytesAccessed = burstSize; 1134 bank.rowAccesses = 1; 1135 1136 prechargeBank(bank, std::max(bank.freeAt, bank.tRASDoneAt) + tRP); 1137 DPRINTF(DRAM, "doDRAMAccess::bank.freeAt is %lld\n", bank.freeAt); 1138 } else 1139 panic("No page management policy chosen\n"); 1140 1141 // Update request parameters 1142 dram_pkt->readyTime = curTick() + addDelay + accessLat + tBURST; 1143 1144 1145 DPRINTF(DRAM, "Req %lld: curtick is %lld accessLat is %d " \ 1146 "readytime is %lld busbusyuntil is %lld. " \ 1147 "Scheduling at readyTime\n", dram_pkt->addr, 1148 curTick(), accessLat, dram_pkt->readyTime, busBusyUntil); 1149 1150 // Make sure requests are not overlapping on the databus 1151 assert(dram_pkt->readyTime - busBusyUntil >= tBURST); 1152 1153 // Update bus state 1154 busBusyUntil = dram_pkt->readyTime; 1155 1156 DPRINTF(DRAM,"Access time is %lld\n", 1157 dram_pkt->readyTime - dram_pkt->entryTime); 1158 1159 // Update the minimum timing between the requests, this is a 1160 // conservative estimate of when we have to schedule the next 1161 // request to not introduce any unecessary bubbles. In most cases 1162 // we will wake up sooner than we have to. 1163 nextReqTime = busBusyUntil - (tRP + tRCD + tCL); 1164 1165 // Update the stats and schedule the next request 1166 if (dram_pkt->isRead) { 1167 ++readsThisTime; 1168 if (rowHitFlag) 1169 readRowHits++; 1170 bytesReadDRAM += burstSize; 1171 perBankRdBursts[dram_pkt->bankId]++; 1172 1173 // Update latency stats 1174 totMemAccLat += dram_pkt->readyTime - dram_pkt->entryTime; 1175 totBankLat += bankLat; 1176 totBusLat += tBURST; 1177 totQLat += dram_pkt->readyTime - dram_pkt->entryTime - bankLat - 1178 tBURST; 1179 } else { 1180 ++writesThisTime; 1181 if (rowHitFlag) 1182 writeRowHits++; 1183 bytesWritten += burstSize; 1184 perBankWrBursts[dram_pkt->bankId]++; 1185 } 1186} 1187 1188void 1189DRAMCtrl::moveToRespQ() 1190{ 1191 // Remove from read queue 1192 DRAMPacket* dram_pkt = readQueue.front(); 1193 readQueue.pop_front(); 1194 1195 // sanity check 1196 assert(dram_pkt->size <= burstSize); 1197 1198 // Insert into response queue sorted by readyTime 1199 // It will be sent back to the requestor at its 1200 // readyTime 1201 if (respQueue.empty()) { 1202 respQueue.push_front(dram_pkt); 1203 assert(!respondEvent.scheduled()); 1204 assert(dram_pkt->readyTime >= curTick()); 1205 schedule(respondEvent, dram_pkt->readyTime); 1206 } else { 1207 bool done = false; 1208 auto i = respQueue.begin(); 1209 while (!done && i != respQueue.end()) { 1210 if ((*i)->readyTime > dram_pkt->readyTime) { 1211 respQueue.insert(i, dram_pkt); 1212 done = true; 1213 } 1214 ++i; 1215 } 1216 1217 if (!done) 1218 respQueue.push_back(dram_pkt); 1219 1220 assert(respondEvent.scheduled()); 1221 1222 if (respQueue.front()->readyTime < respondEvent.when()) { 1223 assert(respQueue.front()->readyTime >= curTick()); 1224 reschedule(respondEvent, respQueue.front()->readyTime); 1225 } 1226 } 1227} 1228 1229void 1230DRAMCtrl::processNextReqEvent() 1231{ 1232 if (busState == READ_TO_WRITE) { 1233 DPRINTF(DRAM, "Switching to writes after %d reads with %d reads " 1234 "waiting\n", readsThisTime, readQueue.size()); 1235 1236 // sample and reset the read-related stats as we are now 1237 // transitioning to writes, and all reads are done 1238 rdPerTurnAround.sample(readsThisTime); 1239 readsThisTime = 0; 1240 1241 // now proceed to do the actual writes 1242 busState = WRITE; 1243 } else if (busState == WRITE_TO_READ) { 1244 DPRINTF(DRAM, "Switching to reads after %d writes with %d writes " 1245 "waiting\n", writesThisTime, writeQueue.size()); 1246 1247 wrPerTurnAround.sample(writesThisTime); 1248 writesThisTime = 0; 1249 1250 busState = READ; 1251 } 1252 1253 if (refreshState != REF_IDLE) { 1254 // if a refresh waiting for this event loop to finish, then hand 1255 // over now, and do not schedule a new nextReqEvent 1256 if (refreshState == REF_DRAIN) { 1257 DPRINTF(DRAM, "Refresh drain done, now precharging\n"); 1258 1259 refreshState = REF_PRE; 1260 1261 // hand control back to the refresh event loop 1262 schedule(refreshEvent, curTick()); 1263 } 1264 1265 // let the refresh finish before issuing any further requests 1266 return; 1267 } 1268 1269 // when we get here it is either a read or a write 1270 if (busState == READ) { 1271 1272 // track if we should switch or not 1273 bool switch_to_writes = false; 1274 1275 if (readQueue.empty()) { 1276 // In the case there is no read request to go next, 1277 // trigger writes if we have passed the low threshold (or 1278 // if we are draining) 1279 if (!writeQueue.empty() && 1280 (drainManager || writeQueue.size() > writeLowThreshold)) { 1281 1282 switch_to_writes = true; 1283 } else { 1284 // check if we are drained 1285 if (respQueue.empty () && drainManager) { 1286 drainManager->signalDrainDone(); 1287 drainManager = NULL; 1288 } 1289 1290 // nothing to do, not even any point in scheduling an 1291 // event for the next request 1292 return; 1293 } 1294 } else { 1295 // Figure out which read request goes next, and move it to the 1296 // front of the read queue 1297 chooseNext(readQueue); 1298 1299 doDRAMAccess(readQueue.front()); 1300 1301 // At this point we're done dealing with the request 1302 // It will be moved to a separate response queue with a 1303 // correct readyTime, and eventually be sent back at that 1304 // time 1305 moveToRespQ(); 1306 1307 // we have so many writes that we have to transition 1308 if (writeQueue.size() > writeHighThreshold) { 1309 switch_to_writes = true; 1310 } 1311 } 1312 1313 // switching to writes, either because the read queue is empty 1314 // and the writes have passed the low threshold (or we are 1315 // draining), or because the writes hit the hight threshold 1316 if (switch_to_writes) { 1317 // transition to writing 1318 busState = READ_TO_WRITE; 1319 1320 // add a bubble to the data bus, as defined by the 1321 // tRTW parameter 1322 busBusyUntil += tRTW; 1323 1324 // update the minimum timing between the requests, 1325 // this shifts us back in time far enough to do any 1326 // bank preparation 1327 nextReqTime = busBusyUntil - (tRP + tRCD + tCL); 1328 } 1329 } else { 1330 chooseNext(writeQueue); 1331 DRAMPacket* dram_pkt = writeQueue.front(); 1332 // sanity check 1333 assert(dram_pkt->size <= burstSize); 1334 doDRAMAccess(dram_pkt); 1335 1336 writeQueue.pop_front(); 1337 delete dram_pkt; 1338 1339 // If we emptied the write queue, or got sufficiently below the 1340 // threshold (using the minWritesPerSwitch as the hysteresis) and 1341 // are not draining, or we have reads waiting and have done enough 1342 // writes, then switch to reads. 1343 if (writeQueue.empty() || 1344 (writeQueue.size() + minWritesPerSwitch < writeLowThreshold && 1345 !drainManager) || 1346 (!readQueue.empty() && writesThisTime >= minWritesPerSwitch)) { 1347 // turn the bus back around for reads again 1348 busState = WRITE_TO_READ; 1349 1350 // note that the we switch back to reads also in the idle 1351 // case, which eventually will check for any draining and 1352 // also pause any further scheduling if there is really 1353 // nothing to do 1354 1355 // here we get a bit creative and shift the bus busy time not 1356 // just the tWTR, but also a CAS latency to capture the fact 1357 // that we are allowed to prepare a new bank, but not issue a 1358 // read command until after tWTR, in essence we capture a 1359 // bubble on the data bus that is tWTR + tCL 1360 busBusyUntil += tWTR + tCL; 1361 1362 // update the minimum timing between the requests, this shifts 1363 // us back in time far enough to do any bank preparation 1364 nextReqTime = busBusyUntil - (tRP + tRCD + tCL); 1365 } 1366 } 1367 1368 schedule(nextReqEvent, std::max(nextReqTime, curTick())); 1369 1370 // If there is space available and we have writes waiting then let 1371 // them retry. This is done here to ensure that the retry does not 1372 // cause a nextReqEvent to be scheduled before we do so as part of 1373 // the next request processing 1374 if (retryWrReq && writeQueue.size() < writeBufferSize) { 1375 retryWrReq = false; 1376 port.sendRetry(); 1377 } 1378} 1379 1380uint64_t 1381DRAMCtrl::minBankFreeAt(const deque<DRAMPacket*>& queue) const 1382{ 1383 uint64_t bank_mask = 0; 1384 Tick freeAt = MaxTick; 1385 1386 // detemrine if we have queued transactions targetting the 1387 // bank in question 1388 vector<bool> got_waiting(ranksPerChannel * banksPerRank, false); 1389 for (auto p = queue.begin(); p != queue.end(); ++p) { 1390 got_waiting[(*p)->bankId] = true; 1391 } 1392 1393 for (int i = 0; i < ranksPerChannel; i++) { 1394 for (int j = 0; j < banksPerRank; j++) { 1395 // if we have waiting requests for the bank, and it is 1396 // amongst the first available, update the mask 1397 if (got_waiting[i * banksPerRank + j] && 1398 banks[i][j].freeAt <= freeAt) { 1399 // reset bank mask if new minimum is found 1400 if (banks[i][j].freeAt < freeAt) 1401 bank_mask = 0; 1402 // set the bit corresponding to the available bank 1403 uint8_t bit_index = i * ranksPerChannel + j; 1404 replaceBits(bank_mask, bit_index, bit_index, 1); 1405 freeAt = banks[i][j].freeAt; 1406 } 1407 } 1408 } 1409 return bank_mask; 1410} 1411 1412void 1413DRAMCtrl::processRefreshEvent() 1414{ 1415 // when first preparing the refresh, remember when it was due 1416 if (refreshState == REF_IDLE) { 1417 // remember when the refresh is due 1418 refreshDueAt = curTick(); 1419 1420 // proceed to drain 1421 refreshState = REF_DRAIN; 1422 1423 DPRINTF(DRAM, "Refresh due\n"); 1424 } 1425 1426 // let any scheduled read or write go ahead, after which it will 1427 // hand control back to this event loop 1428 if (refreshState == REF_DRAIN) { 1429 if (nextReqEvent.scheduled()) { 1430 // hand control over to the request loop until it is 1431 // evaluated next 1432 DPRINTF(DRAM, "Refresh awaiting draining\n"); 1433 1434 return; 1435 } else { 1436 refreshState = REF_PRE; 1437 } 1438 } 1439 1440 // at this point, ensure that all banks are precharged 1441 if (refreshState == REF_PRE) {
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1415 DPRINTF(DRAM, "Precharging all\n");
| 1442 // precharge any active bank if we are not already in the idle 1443 // state 1444 if (pwrState != PWR_IDLE) { 1445 DPRINTF(DRAM, "Precharging all\n"); 1446 for (int i = 0; i < ranksPerChannel; i++) { 1447 for (int j = 0; j < banksPerRank; j++) { 1448 if (banks[i][j].openRow != Bank::NO_ROW) { 1449 // respect both causality and any existing bank 1450 // constraints 1451 Tick free_at = 1452 std::max(std::max(banks[i][j].freeAt, 1453 banks[i][j].tRASDoneAt), 1454 curTick()) + tRP;
|
1416
| 1455
|
1417 // precharge any active bank 1418 for (int i = 0; i < ranksPerChannel; i++) { 1419 for (int j = 0; j < banksPerRank; j++) { 1420 if (banks[i][j].openRow != Bank::NO_ROW) { 1421 // respect both causality and any existing bank 1422 // constraints 1423 Tick free_at = std::max(std::max(banks[i][j].freeAt, 1424 banks[i][j].tRASDoneAt), 1425 curTick()) + tRP; 1426 1427 prechargeBank(banks[i][j], free_at);
| 1456 prechargeBank(banks[i][j], free_at); 1457 }
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1428 } 1429 }
| 1458 } 1459 }
|
| 1460 } else { 1461 DPRINTF(DRAM, "All banks already precharged, starting refresh\n"); 1462 1463 // go ahead and kick the power state machine into gear if 1464 // we are already idle 1465 schedulePowerEvent(PWR_REF, curTick());
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1430 } 1431
| 1466 } 1467
|
1432 if (numBanksActive != 0) 1433 panic("Refresh scheduled with %d active banks\n", numBanksActive); 1434 1435 // advance the state
| |
1436 refreshState = REF_RUN;
| 1468 refreshState = REF_RUN;
|
| 1469 assert(numBanksActive == 0);
|
1437
| 1470
|
1438 // call ourselves in the future 1439 schedule(refreshEvent, std::max(curTick(), idleStartTick));
| 1471 // wait for all banks to be precharged, at which point the 1472 // power state machine will transition to the idle state, and 1473 // automatically move to a refresh, at that point it will also 1474 // call this method to get the refresh event loop going again
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1440 return; 1441 } 1442 1443 // last but not least we perform the actual refresh 1444 if (refreshState == REF_RUN) { 1445 // should never get here with any banks active 1446 assert(numBanksActive == 0);
| 1475 return; 1476 } 1477 1478 // last but not least we perform the actual refresh 1479 if (refreshState == REF_RUN) { 1480 // should never get here with any banks active 1481 assert(numBanksActive == 0);
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| 1482 assert(pwrState == PWR_REF);
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1447 1448 Tick banksFree = curTick() + tRFC; 1449 1450 for (int i = 0; i < ranksPerChannel; i++) { 1451 for (int j = 0; j < banksPerRank; j++) { 1452 banks[i][j].freeAt = banksFree; 1453 } 1454 } 1455 1456 // make sure we did not wait so long that we cannot make up 1457 // for it 1458 if (refreshDueAt + tREFI < banksFree) { 1459 fatal("Refresh was delayed so long we cannot catch up\n"); 1460 } 1461 1462 // compensate for the delay in actually performing the refresh 1463 // when scheduling the next one 1464 schedule(refreshEvent, refreshDueAt + tREFI - tRP); 1465
| 1483 1484 Tick banksFree = curTick() + tRFC; 1485 1486 for (int i = 0; i < ranksPerChannel; i++) { 1487 for (int j = 0; j < banksPerRank; j++) { 1488 banks[i][j].freeAt = banksFree; 1489 } 1490 } 1491 1492 // make sure we did not wait so long that we cannot make up 1493 // for it 1494 if (refreshDueAt + tREFI < banksFree) { 1495 fatal("Refresh was delayed so long we cannot catch up\n"); 1496 } 1497 1498 // compensate for the delay in actually performing the refresh 1499 // when scheduling the next one 1500 schedule(refreshEvent, refreshDueAt + tREFI - tRP); 1501
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1466 // back to business as usual 1467 refreshState = REF_IDLE;
| 1502 assert(!powerEvent.scheduled());
|
1468
| 1503
|
1469 // we are now refreshing until tRFC is done 1470 idleStartTick = banksFree;
| 1504 // move to the idle power state once the refresh is done, this 1505 // will also move the refresh state machine to the refresh 1506 // idle state 1507 schedulePowerEvent(PWR_IDLE, banksFree);
|
1471
| 1508
|
1472 // kick the normal request processing loop into action again 1473 // as early as possible, i.e. when the request is done, the 1474 // scheduling of this event also prevents any new requests 1475 // from going ahead before the scheduled point in time 1476 nextReqTime = banksFree; 1477 schedule(nextReqEvent, nextReqTime);
| 1509 DPRINTF(DRAMState, "Refresh done at %llu and next refresh at %llu\n", 1510 banksFree, refreshDueAt + tREFI);
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1478 } 1479} 1480 1481void
| 1511 } 1512} 1513 1514void
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| 1515DRAMCtrl::schedulePowerEvent(PowerState pwr_state, Tick tick) 1516{ 1517 // respect causality 1518 assert(tick >= curTick()); 1519 1520 if (!powerEvent.scheduled()) { 1521 DPRINTF(DRAMState, "Scheduling power event at %llu to state %d\n", 1522 tick, pwr_state); 1523 1524 // insert the new transition 1525 pwrStateTrans = pwr_state; 1526 1527 schedule(powerEvent, tick); 1528 } else { 1529 panic("Scheduled power event at %llu to state %d, " 1530 "with scheduled event at %llu to %d\n", tick, pwr_state, 1531 powerEvent.when(), pwrStateTrans); 1532 } 1533} 1534 1535void 1536DRAMCtrl::processPowerEvent() 1537{ 1538 // remember where we were, and for how long 1539 Tick duration = curTick() - pwrStateTick; 1540 PowerState prev_state = pwrState; 1541 1542 // update the accounting 1543 pwrStateTime[prev_state] += duration; 1544 1545 pwrState = pwrStateTrans; 1546 pwrStateTick = curTick(); 1547 1548 if (pwrState == PWR_IDLE) { 1549 DPRINTF(DRAMState, "All banks precharged\n"); 1550 1551 // if we were refreshing, make sure we start scheduling requests again 1552 if (prev_state == PWR_REF) { 1553 DPRINTF(DRAMState, "Was refreshing for %llu ticks\n", duration); 1554 assert(pwrState == PWR_IDLE); 1555 1556 // kick things into action again 1557 refreshState = REF_IDLE; 1558 assert(!nextReqEvent.scheduled()); 1559 schedule(nextReqEvent, curTick()); 1560 } else { 1561 assert(prev_state == PWR_ACT); 1562 1563 // if we have a pending refresh, and are now moving to 1564 // the idle state, direclty transition to a refresh 1565 if (refreshState == REF_RUN) { 1566 // there should be nothing waiting at this point 1567 assert(!powerEvent.scheduled()); 1568 1569 // update the state in zero time and proceed below 1570 pwrState = PWR_REF; 1571 } 1572 } 1573 } 1574 1575 // we transition to the refresh state, let the refresh state 1576 // machine know of this state update and let it deal with the 1577 // scheduling of the next power state transition as well as the 1578 // following refresh 1579 if (pwrState == PWR_REF) { 1580 DPRINTF(DRAMState, "Refreshing\n"); 1581 // kick the refresh event loop into action again, and that 1582 // in turn will schedule a transition to the idle power 1583 // state once the refresh is done 1584 assert(refreshState == REF_RUN); 1585 processRefreshEvent(); 1586 } 1587} 1588 1589void
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1482DRAMCtrl::regStats() 1483{ 1484 using namespace Stats; 1485 1486 AbstractMemory::regStats(); 1487 1488 readReqs 1489 .name(name() + ".readReqs") 1490 .desc("Number of read requests accepted"); 1491 1492 writeReqs 1493 .name(name() + ".writeReqs") 1494 .desc("Number of write requests accepted"); 1495 1496 readBursts 1497 .name(name() + ".readBursts") 1498 .desc("Number of DRAM read bursts, " 1499 "including those serviced by the write queue"); 1500 1501 writeBursts 1502 .name(name() + ".writeBursts") 1503 .desc("Number of DRAM write bursts, " 1504 "including those merged in the write queue"); 1505 1506 servicedByWrQ 1507 .name(name() + ".servicedByWrQ") 1508 .desc("Number of DRAM read bursts serviced by the write queue"); 1509 1510 mergedWrBursts 1511 .name(name() + ".mergedWrBursts") 1512 .desc("Number of DRAM write bursts merged with an existing one"); 1513 1514 neitherReadNorWrite 1515 .name(name() + ".neitherReadNorWriteReqs") 1516 .desc("Number of requests that are neither read nor write"); 1517 1518 perBankRdBursts 1519 .init(banksPerRank * ranksPerChannel) 1520 .name(name() + ".perBankRdBursts") 1521 .desc("Per bank write bursts"); 1522 1523 perBankWrBursts 1524 .init(banksPerRank * ranksPerChannel) 1525 .name(name() + ".perBankWrBursts") 1526 .desc("Per bank write bursts"); 1527 1528 avgRdQLen 1529 .name(name() + ".avgRdQLen") 1530 .desc("Average read queue length when enqueuing") 1531 .precision(2); 1532 1533 avgWrQLen 1534 .name(name() + ".avgWrQLen") 1535 .desc("Average write queue length when enqueuing") 1536 .precision(2); 1537 1538 totQLat 1539 .name(name() + ".totQLat") 1540 .desc("Total ticks spent queuing"); 1541 1542 totBankLat 1543 .name(name() + ".totBankLat") 1544 .desc("Total ticks spent accessing banks"); 1545 1546 totBusLat 1547 .name(name() + ".totBusLat") 1548 .desc("Total ticks spent in databus transfers"); 1549 1550 totMemAccLat 1551 .name(name() + ".totMemAccLat") 1552 .desc("Total ticks spent from burst creation until serviced " 1553 "by the DRAM"); 1554 1555 avgQLat 1556 .name(name() + ".avgQLat") 1557 .desc("Average queueing delay per DRAM burst") 1558 .precision(2); 1559 1560 avgQLat = totQLat / (readBursts - servicedByWrQ); 1561 1562 avgBankLat 1563 .name(name() + ".avgBankLat") 1564 .desc("Average bank access latency per DRAM burst") 1565 .precision(2); 1566 1567 avgBankLat = totBankLat / (readBursts - servicedByWrQ); 1568 1569 avgBusLat 1570 .name(name() + ".avgBusLat") 1571 .desc("Average bus latency per DRAM burst") 1572 .precision(2); 1573 1574 avgBusLat = totBusLat / (readBursts - servicedByWrQ); 1575 1576 avgMemAccLat 1577 .name(name() + ".avgMemAccLat") 1578 .desc("Average memory access latency per DRAM burst") 1579 .precision(2); 1580 1581 avgMemAccLat = totMemAccLat / (readBursts - servicedByWrQ); 1582 1583 numRdRetry 1584 .name(name() + ".numRdRetry") 1585 .desc("Number of times read queue was full causing retry"); 1586 1587 numWrRetry 1588 .name(name() + ".numWrRetry") 1589 .desc("Number of times write queue was full causing retry"); 1590 1591 readRowHits 1592 .name(name() + ".readRowHits") 1593 .desc("Number of row buffer hits during reads"); 1594 1595 writeRowHits 1596 .name(name() + ".writeRowHits") 1597 .desc("Number of row buffer hits during writes"); 1598 1599 readRowHitRate 1600 .name(name() + ".readRowHitRate") 1601 .desc("Row buffer hit rate for reads") 1602 .precision(2); 1603 1604 readRowHitRate = (readRowHits / (readBursts - servicedByWrQ)) * 100; 1605 1606 writeRowHitRate 1607 .name(name() + ".writeRowHitRate") 1608 .desc("Row buffer hit rate for writes") 1609 .precision(2); 1610 1611 writeRowHitRate = (writeRowHits / (writeBursts - mergedWrBursts)) * 100; 1612 1613 readPktSize 1614 .init(ceilLog2(burstSize) + 1) 1615 .name(name() + ".readPktSize") 1616 .desc("Read request sizes (log2)"); 1617 1618 writePktSize 1619 .init(ceilLog2(burstSize) + 1) 1620 .name(name() + ".writePktSize") 1621 .desc("Write request sizes (log2)"); 1622 1623 rdQLenPdf 1624 .init(readBufferSize) 1625 .name(name() + ".rdQLenPdf") 1626 .desc("What read queue length does an incoming req see"); 1627 1628 wrQLenPdf 1629 .init(writeBufferSize) 1630 .name(name() + ".wrQLenPdf") 1631 .desc("What write queue length does an incoming req see"); 1632 1633 bytesPerActivate 1634 .init(maxAccessesPerRow) 1635 .name(name() + ".bytesPerActivate") 1636 .desc("Bytes accessed per row activation") 1637 .flags(nozero); 1638 1639 rdPerTurnAround 1640 .init(readBufferSize) 1641 .name(name() + ".rdPerTurnAround") 1642 .desc("Reads before turning the bus around for writes") 1643 .flags(nozero); 1644 1645 wrPerTurnAround 1646 .init(writeBufferSize) 1647 .name(name() + ".wrPerTurnAround") 1648 .desc("Writes before turning the bus around for reads") 1649 .flags(nozero); 1650 1651 bytesReadDRAM 1652 .name(name() + ".bytesReadDRAM") 1653 .desc("Total number of bytes read from DRAM"); 1654 1655 bytesReadWrQ 1656 .name(name() + ".bytesReadWrQ") 1657 .desc("Total number of bytes read from write queue"); 1658 1659 bytesWritten 1660 .name(name() + ".bytesWritten") 1661 .desc("Total number of bytes written to DRAM"); 1662 1663 bytesReadSys 1664 .name(name() + ".bytesReadSys") 1665 .desc("Total read bytes from the system interface side"); 1666 1667 bytesWrittenSys 1668 .name(name() + ".bytesWrittenSys") 1669 .desc("Total written bytes from the system interface side"); 1670 1671 avgRdBW 1672 .name(name() + ".avgRdBW") 1673 .desc("Average DRAM read bandwidth in MiByte/s") 1674 .precision(2); 1675 1676 avgRdBW = (bytesReadDRAM / 1000000) / simSeconds; 1677 1678 avgWrBW 1679 .name(name() + ".avgWrBW") 1680 .desc("Average achieved write bandwidth in MiByte/s") 1681 .precision(2); 1682 1683 avgWrBW = (bytesWritten / 1000000) / simSeconds; 1684 1685 avgRdBWSys 1686 .name(name() + ".avgRdBWSys") 1687 .desc("Average system read bandwidth in MiByte/s") 1688 .precision(2); 1689 1690 avgRdBWSys = (bytesReadSys / 1000000) / simSeconds; 1691 1692 avgWrBWSys 1693 .name(name() + ".avgWrBWSys") 1694 .desc("Average system write bandwidth in MiByte/s") 1695 .precision(2); 1696 1697 avgWrBWSys = (bytesWrittenSys / 1000000) / simSeconds; 1698 1699 peakBW 1700 .name(name() + ".peakBW") 1701 .desc("Theoretical peak bandwidth in MiByte/s") 1702 .precision(2); 1703 1704 peakBW = (SimClock::Frequency / tBURST) * burstSize / 1000000; 1705 1706 busUtil 1707 .name(name() + ".busUtil") 1708 .desc("Data bus utilization in percentage") 1709 .precision(2); 1710 1711 busUtil = (avgRdBW + avgWrBW) / peakBW * 100; 1712 1713 totGap 1714 .name(name() + ".totGap") 1715 .desc("Total gap between requests"); 1716 1717 avgGap 1718 .name(name() + ".avgGap") 1719 .desc("Average gap between requests") 1720 .precision(2); 1721 1722 avgGap = totGap / (readReqs + writeReqs); 1723 1724 // Stats for DRAM Power calculation based on Micron datasheet 1725 busUtilRead 1726 .name(name() + ".busUtilRead") 1727 .desc("Data bus utilization in percentage for reads") 1728 .precision(2); 1729 1730 busUtilRead = avgRdBW / peakBW * 100; 1731 1732 busUtilWrite 1733 .name(name() + ".busUtilWrite") 1734 .desc("Data bus utilization in percentage for writes") 1735 .precision(2); 1736 1737 busUtilWrite = avgWrBW / peakBW * 100; 1738 1739 pageHitRate 1740 .name(name() + ".pageHitRate") 1741 .desc("Row buffer hit rate, read and write combined") 1742 .precision(2); 1743 1744 pageHitRate = (writeRowHits + readRowHits) / 1745 (writeBursts - mergedWrBursts + readBursts - servicedByWrQ) * 100; 1746
| 1590DRAMCtrl::regStats() 1591{ 1592 using namespace Stats; 1593 1594 AbstractMemory::regStats(); 1595 1596 readReqs 1597 .name(name() + ".readReqs") 1598 .desc("Number of read requests accepted"); 1599 1600 writeReqs 1601 .name(name() + ".writeReqs") 1602 .desc("Number of write requests accepted"); 1603 1604 readBursts 1605 .name(name() + ".readBursts") 1606 .desc("Number of DRAM read bursts, " 1607 "including those serviced by the write queue"); 1608 1609 writeBursts 1610 .name(name() + ".writeBursts") 1611 .desc("Number of DRAM write bursts, " 1612 "including those merged in the write queue"); 1613 1614 servicedByWrQ 1615 .name(name() + ".servicedByWrQ") 1616 .desc("Number of DRAM read bursts serviced by the write queue"); 1617 1618 mergedWrBursts 1619 .name(name() + ".mergedWrBursts") 1620 .desc("Number of DRAM write bursts merged with an existing one"); 1621 1622 neitherReadNorWrite 1623 .name(name() + ".neitherReadNorWriteReqs") 1624 .desc("Number of requests that are neither read nor write"); 1625 1626 perBankRdBursts 1627 .init(banksPerRank * ranksPerChannel) 1628 .name(name() + ".perBankRdBursts") 1629 .desc("Per bank write bursts"); 1630 1631 perBankWrBursts 1632 .init(banksPerRank * ranksPerChannel) 1633 .name(name() + ".perBankWrBursts") 1634 .desc("Per bank write bursts"); 1635 1636 avgRdQLen 1637 .name(name() + ".avgRdQLen") 1638 .desc("Average read queue length when enqueuing") 1639 .precision(2); 1640 1641 avgWrQLen 1642 .name(name() + ".avgWrQLen") 1643 .desc("Average write queue length when enqueuing") 1644 .precision(2); 1645 1646 totQLat 1647 .name(name() + ".totQLat") 1648 .desc("Total ticks spent queuing"); 1649 1650 totBankLat 1651 .name(name() + ".totBankLat") 1652 .desc("Total ticks spent accessing banks"); 1653 1654 totBusLat 1655 .name(name() + ".totBusLat") 1656 .desc("Total ticks spent in databus transfers"); 1657 1658 totMemAccLat 1659 .name(name() + ".totMemAccLat") 1660 .desc("Total ticks spent from burst creation until serviced " 1661 "by the DRAM"); 1662 1663 avgQLat 1664 .name(name() + ".avgQLat") 1665 .desc("Average queueing delay per DRAM burst") 1666 .precision(2); 1667 1668 avgQLat = totQLat / (readBursts - servicedByWrQ); 1669 1670 avgBankLat 1671 .name(name() + ".avgBankLat") 1672 .desc("Average bank access latency per DRAM burst") 1673 .precision(2); 1674 1675 avgBankLat = totBankLat / (readBursts - servicedByWrQ); 1676 1677 avgBusLat 1678 .name(name() + ".avgBusLat") 1679 .desc("Average bus latency per DRAM burst") 1680 .precision(2); 1681 1682 avgBusLat = totBusLat / (readBursts - servicedByWrQ); 1683 1684 avgMemAccLat 1685 .name(name() + ".avgMemAccLat") 1686 .desc("Average memory access latency per DRAM burst") 1687 .precision(2); 1688 1689 avgMemAccLat = totMemAccLat / (readBursts - servicedByWrQ); 1690 1691 numRdRetry 1692 .name(name() + ".numRdRetry") 1693 .desc("Number of times read queue was full causing retry"); 1694 1695 numWrRetry 1696 .name(name() + ".numWrRetry") 1697 .desc("Number of times write queue was full causing retry"); 1698 1699 readRowHits 1700 .name(name() + ".readRowHits") 1701 .desc("Number of row buffer hits during reads"); 1702 1703 writeRowHits 1704 .name(name() + ".writeRowHits") 1705 .desc("Number of row buffer hits during writes"); 1706 1707 readRowHitRate 1708 .name(name() + ".readRowHitRate") 1709 .desc("Row buffer hit rate for reads") 1710 .precision(2); 1711 1712 readRowHitRate = (readRowHits / (readBursts - servicedByWrQ)) * 100; 1713 1714 writeRowHitRate 1715 .name(name() + ".writeRowHitRate") 1716 .desc("Row buffer hit rate for writes") 1717 .precision(2); 1718 1719 writeRowHitRate = (writeRowHits / (writeBursts - mergedWrBursts)) * 100; 1720 1721 readPktSize 1722 .init(ceilLog2(burstSize) + 1) 1723 .name(name() + ".readPktSize") 1724 .desc("Read request sizes (log2)"); 1725 1726 writePktSize 1727 .init(ceilLog2(burstSize) + 1) 1728 .name(name() + ".writePktSize") 1729 .desc("Write request sizes (log2)"); 1730 1731 rdQLenPdf 1732 .init(readBufferSize) 1733 .name(name() + ".rdQLenPdf") 1734 .desc("What read queue length does an incoming req see"); 1735 1736 wrQLenPdf 1737 .init(writeBufferSize) 1738 .name(name() + ".wrQLenPdf") 1739 .desc("What write queue length does an incoming req see"); 1740 1741 bytesPerActivate 1742 .init(maxAccessesPerRow) 1743 .name(name() + ".bytesPerActivate") 1744 .desc("Bytes accessed per row activation") 1745 .flags(nozero); 1746 1747 rdPerTurnAround 1748 .init(readBufferSize) 1749 .name(name() + ".rdPerTurnAround") 1750 .desc("Reads before turning the bus around for writes") 1751 .flags(nozero); 1752 1753 wrPerTurnAround 1754 .init(writeBufferSize) 1755 .name(name() + ".wrPerTurnAround") 1756 .desc("Writes before turning the bus around for reads") 1757 .flags(nozero); 1758 1759 bytesReadDRAM 1760 .name(name() + ".bytesReadDRAM") 1761 .desc("Total number of bytes read from DRAM"); 1762 1763 bytesReadWrQ 1764 .name(name() + ".bytesReadWrQ") 1765 .desc("Total number of bytes read from write queue"); 1766 1767 bytesWritten 1768 .name(name() + ".bytesWritten") 1769 .desc("Total number of bytes written to DRAM"); 1770 1771 bytesReadSys 1772 .name(name() + ".bytesReadSys") 1773 .desc("Total read bytes from the system interface side"); 1774 1775 bytesWrittenSys 1776 .name(name() + ".bytesWrittenSys") 1777 .desc("Total written bytes from the system interface side"); 1778 1779 avgRdBW 1780 .name(name() + ".avgRdBW") 1781 .desc("Average DRAM read bandwidth in MiByte/s") 1782 .precision(2); 1783 1784 avgRdBW = (bytesReadDRAM / 1000000) / simSeconds; 1785 1786 avgWrBW 1787 .name(name() + ".avgWrBW") 1788 .desc("Average achieved write bandwidth in MiByte/s") 1789 .precision(2); 1790 1791 avgWrBW = (bytesWritten / 1000000) / simSeconds; 1792 1793 avgRdBWSys 1794 .name(name() + ".avgRdBWSys") 1795 .desc("Average system read bandwidth in MiByte/s") 1796 .precision(2); 1797 1798 avgRdBWSys = (bytesReadSys / 1000000) / simSeconds; 1799 1800 avgWrBWSys 1801 .name(name() + ".avgWrBWSys") 1802 .desc("Average system write bandwidth in MiByte/s") 1803 .precision(2); 1804 1805 avgWrBWSys = (bytesWrittenSys / 1000000) / simSeconds; 1806 1807 peakBW 1808 .name(name() + ".peakBW") 1809 .desc("Theoretical peak bandwidth in MiByte/s") 1810 .precision(2); 1811 1812 peakBW = (SimClock::Frequency / tBURST) * burstSize / 1000000; 1813 1814 busUtil 1815 .name(name() + ".busUtil") 1816 .desc("Data bus utilization in percentage") 1817 .precision(2); 1818 1819 busUtil = (avgRdBW + avgWrBW) / peakBW * 100; 1820 1821 totGap 1822 .name(name() + ".totGap") 1823 .desc("Total gap between requests"); 1824 1825 avgGap 1826 .name(name() + ".avgGap") 1827 .desc("Average gap between requests") 1828 .precision(2); 1829 1830 avgGap = totGap / (readReqs + writeReqs); 1831 1832 // Stats for DRAM Power calculation based on Micron datasheet 1833 busUtilRead 1834 .name(name() + ".busUtilRead") 1835 .desc("Data bus utilization in percentage for reads") 1836 .precision(2); 1837 1838 busUtilRead = avgRdBW / peakBW * 100; 1839 1840 busUtilWrite 1841 .name(name() + ".busUtilWrite") 1842 .desc("Data bus utilization in percentage for writes") 1843 .precision(2); 1844 1845 busUtilWrite = avgWrBW / peakBW * 100; 1846 1847 pageHitRate 1848 .name(name() + ".pageHitRate") 1849 .desc("Row buffer hit rate, read and write combined") 1850 .precision(2); 1851 1852 pageHitRate = (writeRowHits + readRowHits) / 1853 (writeBursts - mergedWrBursts + readBursts - servicedByWrQ) * 100; 1854
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1747 prechargeAllPercent 1748 .name(name() + ".prechargeAllPercent") 1749 .desc("Percentage of time for which DRAM has all the banks in " 1750 "precharge state") 1751 .precision(2); 1752 1753 prechargeAllPercent = prechargeAllTime / simTicks * 100;
| 1855 pwrStateTime 1856 .init(5) 1857 .name(name() + ".memoryStateTime") 1858 .desc("Time in different power states"); 1859 pwrStateTime.subname(0, "IDLE"); 1860 pwrStateTime.subname(1, "REF"); 1861 pwrStateTime.subname(2, "PRE_PDN"); 1862 pwrStateTime.subname(3, "ACT"); 1863 pwrStateTime.subname(4, "ACT_PDN");
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1754} 1755 1756void 1757DRAMCtrl::recvFunctional(PacketPtr pkt) 1758{ 1759 // rely on the abstract memory 1760 functionalAccess(pkt); 1761} 1762 1763BaseSlavePort& 1764DRAMCtrl::getSlavePort(const string &if_name, PortID idx) 1765{ 1766 if (if_name != "port") { 1767 return MemObject::getSlavePort(if_name, idx); 1768 } else { 1769 return port; 1770 } 1771} 1772 1773unsigned int 1774DRAMCtrl::drain(DrainManager *dm) 1775{ 1776 unsigned int count = port.drain(dm); 1777 1778 // if there is anything in any of our internal queues, keep track 1779 // of that as well 1780 if (!(writeQueue.empty() && readQueue.empty() && 1781 respQueue.empty())) { 1782 DPRINTF(Drain, "DRAM controller not drained, write: %d, read: %d," 1783 " resp: %d\n", writeQueue.size(), readQueue.size(), 1784 respQueue.size()); 1785 ++count; 1786 drainManager = dm; 1787 1788 // the only part that is not drained automatically over time 1789 // is the write queue, thus kick things into action if needed 1790 if (!writeQueue.empty() && !nextReqEvent.scheduled()) { 1791 schedule(nextReqEvent, curTick()); 1792 } 1793 } 1794 1795 if (count) 1796 setDrainState(Drainable::Draining); 1797 else 1798 setDrainState(Drainable::Drained); 1799 return count; 1800} 1801 1802DRAMCtrl::MemoryPort::MemoryPort(const std::string& name, DRAMCtrl& _memory) 1803 : QueuedSlavePort(name, &_memory, queue), queue(_memory, *this), 1804 memory(_memory) 1805{ } 1806 1807AddrRangeList 1808DRAMCtrl::MemoryPort::getAddrRanges() const 1809{ 1810 AddrRangeList ranges; 1811 ranges.push_back(memory.getAddrRange()); 1812 return ranges; 1813} 1814 1815void 1816DRAMCtrl::MemoryPort::recvFunctional(PacketPtr pkt) 1817{ 1818 pkt->pushLabel(memory.name()); 1819 1820 if (!queue.checkFunctional(pkt)) { 1821 // Default implementation of SimpleTimingPort::recvFunctional() 1822 // calls recvAtomic() and throws away the latency; we can save a 1823 // little here by just not calculating the latency. 1824 memory.recvFunctional(pkt); 1825 } 1826 1827 pkt->popLabel(); 1828} 1829 1830Tick 1831DRAMCtrl::MemoryPort::recvAtomic(PacketPtr pkt) 1832{ 1833 return memory.recvAtomic(pkt); 1834} 1835 1836bool 1837DRAMCtrl::MemoryPort::recvTimingReq(PacketPtr pkt) 1838{ 1839 // pass it to the memory controller 1840 return memory.recvTimingReq(pkt); 1841} 1842 1843DRAMCtrl* 1844DRAMCtrlParams::create() 1845{ 1846 return new DRAMCtrl(this); 1847}
| 1864} 1865 1866void 1867DRAMCtrl::recvFunctional(PacketPtr pkt) 1868{ 1869 // rely on the abstract memory 1870 functionalAccess(pkt); 1871} 1872 1873BaseSlavePort& 1874DRAMCtrl::getSlavePort(const string &if_name, PortID idx) 1875{ 1876 if (if_name != "port") { 1877 return MemObject::getSlavePort(if_name, idx); 1878 } else { 1879 return port; 1880 } 1881} 1882 1883unsigned int 1884DRAMCtrl::drain(DrainManager *dm) 1885{ 1886 unsigned int count = port.drain(dm); 1887 1888 // if there is anything in any of our internal queues, keep track 1889 // of that as well 1890 if (!(writeQueue.empty() && readQueue.empty() && 1891 respQueue.empty())) { 1892 DPRINTF(Drain, "DRAM controller not drained, write: %d, read: %d," 1893 " resp: %d\n", writeQueue.size(), readQueue.size(), 1894 respQueue.size()); 1895 ++count; 1896 drainManager = dm; 1897 1898 // the only part that is not drained automatically over time 1899 // is the write queue, thus kick things into action if needed 1900 if (!writeQueue.empty() && !nextReqEvent.scheduled()) { 1901 schedule(nextReqEvent, curTick()); 1902 } 1903 } 1904 1905 if (count) 1906 setDrainState(Drainable::Draining); 1907 else 1908 setDrainState(Drainable::Drained); 1909 return count; 1910} 1911 1912DRAMCtrl::MemoryPort::MemoryPort(const std::string& name, DRAMCtrl& _memory) 1913 : QueuedSlavePort(name, &_memory, queue), queue(_memory, *this), 1914 memory(_memory) 1915{ } 1916 1917AddrRangeList 1918DRAMCtrl::MemoryPort::getAddrRanges() const 1919{ 1920 AddrRangeList ranges; 1921 ranges.push_back(memory.getAddrRange()); 1922 return ranges; 1923} 1924 1925void 1926DRAMCtrl::MemoryPort::recvFunctional(PacketPtr pkt) 1927{ 1928 pkt->pushLabel(memory.name()); 1929 1930 if (!queue.checkFunctional(pkt)) { 1931 // Default implementation of SimpleTimingPort::recvFunctional() 1932 // calls recvAtomic() and throws away the latency; we can save a 1933 // little here by just not calculating the latency. 1934 memory.recvFunctional(pkt); 1935 } 1936 1937 pkt->popLabel(); 1938} 1939 1940Tick 1941DRAMCtrl::MemoryPort::recvAtomic(PacketPtr pkt) 1942{ 1943 return memory.recvAtomic(pkt); 1944} 1945 1946bool 1947DRAMCtrl::MemoryPort::recvTimingReq(PacketPtr pkt) 1948{ 1949 // pass it to the memory controller 1950 return memory.recvTimingReq(pkt); 1951} 1952 1953DRAMCtrl* 1954DRAMCtrlParams::create() 1955{ 1956 return new DRAMCtrl(this); 1957}
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