1/* 2 * Copyright 2018 Google, Inc. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: redistributions of source code must retain the above copyright 7 * notice, this list of conditions and the following disclaimer; 8 * redistributions in binary form must reproduce the above copyright 9 * notice, this list of conditions and the following disclaimer in the 10 * documentation and/or other materials provided with the distribution; 11 * neither the name of the copyright holders nor the names of its 12 * contributors may be used to endorse or promote products derived from 13 * this software without specific prior written permission. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 19 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * Authors: Gabe Black 28 */ 29 30#include "systemc/core/scheduler.hh" 31 32#include "base/fiber.hh" 33#include "base/logging.hh" 34#include "sim/eventq.hh" 35#include "systemc/core/kernel.hh" 36#include "systemc/ext/core/sc_main.hh" 37#include "systemc/ext/utils/sc_report.hh" 38#include "systemc/ext/utils/sc_report_handler.hh" 39#include "systemc/utils/tracefile.hh" 40 41namespace sc_gem5 42{ 43 44Scheduler::Scheduler() : 45 eq(nullptr), readyEvent(this, false, ReadyPriority), 46 pauseEvent(this, false, PausePriority), 47 stopEvent(this, false, StopPriority), 48 scMain(nullptr), _throwToScMain(nullptr), 49 starvationEvent(this, false, StarvationPriority), 50 _elaborationDone(false), _started(false), _stopNow(false), 51 _status(StatusOther), maxTickEvent(this, false, MaxTickPriority), 52 timeAdvancesEvent(this, false, TimeAdvancesPriority), _numCycles(0), 53 _changeStamp(0), _current(nullptr), initDone(false), runOnce(false) 54{} 55 56Scheduler::~Scheduler() 57{ 58 // Clear out everything that belongs to us to make sure nobody tries to 59 // clear themselves out after the scheduler goes away. 60 clear(); 61} 62 63void 64Scheduler::clear() 65{ 66 // Delta notifications. 67 while (!deltas.empty()) 68 deltas.front()->deschedule(); 69 70 // Timed notifications. 71 for (auto &tsp: timeSlots) { 72 TimeSlot *&ts = tsp.second; 73 while (!ts->events.empty()) 74 ts->events.front()->deschedule(); 75 deschedule(ts); 76 } 77 timeSlots.clear(); 78 79 // gem5 events. 80 if (readyEvent.scheduled()) 81 deschedule(&readyEvent); 82 if (pauseEvent.scheduled()) 83 deschedule(&pauseEvent); 84 if (stopEvent.scheduled()) 85 deschedule(&stopEvent); 86 if (starvationEvent.scheduled()) 87 deschedule(&starvationEvent); 88 if (maxTickEvent.scheduled()) 89 deschedule(&maxTickEvent); 90 if (timeAdvancesEvent.scheduled()) 91 deschedule(&timeAdvancesEvent); 92 93 Process *p; 94 while ((p = initList.getNext())) 95 p->popListNode(); 96 while ((p = readyListMethods.getNext())) 97 p->popListNode(); 98 while ((p = readyListThreads.getNext())) 99 p->popListNode(); 100 101 Channel *c; 102 while ((c = updateList.getNext())) 103 c->popListNode(); 104} 105 106void 107Scheduler::initPhase() 108{ 109 for (Process *p = initList.getNext(); p; p = initList.getNext()) { 110 p->popListNode(); 111 112 if (p->dontInitialize()) { 113 if (!p->hasStaticSensitivities() && !p->internal()) { 114 SC_REPORT_WARNING( 115 "(W558) disable() or dont_initialize() called on " 116 "process with no static sensitivity, it will be " 117 "orphaned", p->name()); 118 } 119 } else { 120 p->ready(); 121 } 122 } 123 124 runUpdate(); 125 runDelta(); 126 127 for (auto ets: eventsToSchedule) 128 eq->schedule(ets.first, ets.second); 129 eventsToSchedule.clear(); 130 131 if (_started) { 132 if (!runToTime && starved()) 133 scheduleStarvationEvent(); 134 kernel->status(::sc_core::SC_RUNNING); 135 } 136 137 initDone = true; 138 139 status(StatusOther); 140 141 scheduleTimeAdvancesEvent(); 142} 143 144void 145Scheduler::reg(Process *p) 146{ 147 if (initDone) { 148 // If not marked as dontInitialize, mark as ready. 149 if (!p->dontInitialize()) 150 p->ready(); 151 } else { 152 // Otherwise, record that this process should be initialized once we 153 // get there. 154 initList.pushLast(p); 155 } 156} 157 158void 159Scheduler::yield() 160{ 161 // Pull a process from the active list. 162 _current = getNextReady(); 163 if (!_current) { 164 // There are no more processes, so return control to evaluate. 165 Fiber::primaryFiber()->run(); 166 } else { 167 _current->popListNode(); 168 // Switch to whatever Fiber is supposed to run this process. All 169 // Fibers which aren't running should be parked at this line. 170 _current->fiber()->run(); 171 // If the current process needs to be manually started, start it. 172 if (_current && _current->needsStart()) { 173 _current->needsStart(false); 174 try { 175 _current->run(); 176 } catch (...) { 177 throwToScMain(); 178 } 179 } 180 } 181 if (_current && !_current->needsStart()) { 182 if (_current->excWrapper) { 183 auto ew = _current->excWrapper; 184 _current->excWrapper = nullptr; 185 ew->throw_it(); 186 } else if (_current->inReset()) { 187 _current->reset(false); 188 } 189 } 190} 191 192void 193Scheduler::ready(Process *p) 194{ 195 if (_stopNow) 196 return; 197 198 if (p->procKind() == ::sc_core::SC_METHOD_PROC_) 199 readyListMethods.pushLast(p); 200 else 201 readyListThreads.pushLast(p); 202 203 if (!inEvaluate()) 204 scheduleReadyEvent(); 205} 206 207void 208Scheduler::resume(Process *p) 209{ 210 if (initDone) 211 ready(p); 212 else 213 initList.pushLast(p); 214} 215 216bool 217listContains(ListNode *list, ListNode *target) 218{ 219 ListNode *n = list->nextListNode; 220 while (n != list) 221 if (n == target) 222 return true; 223 return false; 224} 225 226bool 227Scheduler::suspend(Process *p) 228{ 229 bool was_ready; 230 if (initDone) { 231 // After initialization, check if we're on a ready list. 232 was_ready = (p->nextListNode != nullptr); 233 p->popListNode(); 234 } else { 235 // Nothing is ready before init. 236 was_ready = false; 237 } 238 return was_ready; 239} 240 241void 242Scheduler::requestUpdate(Channel *c) 243{ 244 updateList.pushLast(c); 245 if (!inEvaluate()) 246 scheduleReadyEvent(); 247} 248 249void 250Scheduler::scheduleReadyEvent() 251{ 252 // Schedule the evaluate and update phases. 253 if (!readyEvent.scheduled()) { 254 schedule(&readyEvent); 255 if (starvationEvent.scheduled()) 256 deschedule(&starvationEvent); 257 } 258} 259 260void 261Scheduler::scheduleStarvationEvent() 262{ 263 if (!starvationEvent.scheduled()) { 264 schedule(&starvationEvent); 265 if (readyEvent.scheduled()) 266 deschedule(&readyEvent); 267 } 268} 269 270void 271Scheduler::runReady() 272{ 273 scheduleTimeAdvancesEvent(); 274 275 bool empty = readyListMethods.empty() && readyListThreads.empty(); 276 lastReadyTick = getCurTick(); 277 278 // The evaluation phase. 279 status(StatusEvaluate); 280 do { 281 yield(); 282 } while (getNextReady());
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284 285 if (!empty) { 286 _numCycles++; 287 _changeStamp++; 288 } 289 290 if (_stopNow) { 291 status(StatusOther); 292 return; 293 } 294 295 runUpdate(); 296 if (!traceFiles.empty()) 297 trace(true); 298 runDelta(); 299 300 if (!runToTime && starved()) 301 scheduleStarvationEvent(); 302 303 if (runOnce) 304 schedulePause(); 305 306 status(StatusOther); 307} 308 309void 310Scheduler::runUpdate() 311{ 312 status(StatusUpdate); 313 314 try { 315 Channel *channel = updateList.getNext(); 316 while (channel) { 317 channel->popListNode(); 318 channel->update(); 319 channel = updateList.getNext(); 320 } 321 } catch (...) { 322 throwToScMain(); 323 } 324} 325 326void 327Scheduler::runDelta() 328{ 329 status(StatusDelta); 330 331 try { 332 while (!deltas.empty()) 333 deltas.front()->run(); 334 } catch (...) { 335 throwToScMain(); 336 } 337} 338 339void 340Scheduler::pause() 341{ 342 status(StatusPaused); 343 kernel->status(::sc_core::SC_PAUSED); 344 runOnce = false; 345 if (scMain && !scMain->finished()) 346 scMain->run(); 347} 348 349void 350Scheduler::stop() 351{ 352 status(StatusStopped); 353 kernel->stop(); 354 355 clear(); 356 357 runOnce = false; 358 if (scMain && !scMain->finished()) 359 scMain->run(); 360} 361 362void 363Scheduler::start(Tick max_tick, bool run_to_time) 364{ 365 // We should be running from sc_main. Keep track of that Fiber to return 366 // to later. 367 scMain = Fiber::currentFiber(); 368 369 _started = true; 370 status(StatusOther); 371 runToTime = run_to_time; 372 373 maxTick = max_tick; 374 lastReadyTick = getCurTick(); 375 376 if (initDone) { 377 if (!runToTime && starved()) 378 scheduleStarvationEvent(); 379 kernel->status(::sc_core::SC_RUNNING); 380 } 381 382 schedule(&maxTickEvent, maxTick); 383 scheduleTimeAdvancesEvent(); 384 385 // Return to gem5 to let it run events, etc. 386 Fiber::primaryFiber()->run(); 387 388 if (pauseEvent.scheduled()) 389 deschedule(&pauseEvent); 390 if (stopEvent.scheduled()) 391 deschedule(&stopEvent); 392 if (maxTickEvent.scheduled()) 393 deschedule(&maxTickEvent); 394 if (starvationEvent.scheduled()) 395 deschedule(&starvationEvent); 396 397 if (_throwToScMain) { 398 const ::sc_core::sc_report *to_throw = _throwToScMain; 399 _throwToScMain = nullptr; 400 throw *to_throw; 401 } 402} 403 404void 405Scheduler::oneCycle() 406{ 407 runOnce = true; 408 scheduleReadyEvent(); 409 start(::MaxTick, false); 410} 411 412void 413Scheduler::schedulePause() 414{ 415 if (pauseEvent.scheduled()) 416 return; 417 418 schedule(&pauseEvent); 419} 420 421void 422Scheduler::throwToScMain() 423{ 424 ::sc_core::sc_report report = reportifyException(); 425 _throwToScMain = &report; 426 status(StatusOther); 427 scMain->run(); 428} 429 430void 431Scheduler::scheduleStop(bool finish_delta) 432{ 433 if (stopEvent.scheduled()) 434 return; 435 436 if (!finish_delta) { 437 _stopNow = true; 438 // If we're not supposed to finish the delta cycle, flush all 439 // pending activity. 440 clear(); 441 } 442 schedule(&stopEvent); 443} 444 445void 446Scheduler::trace(bool delta) 447{ 448 for (auto tf: traceFiles) 449 tf->trace(delta); 450} 451 452Scheduler scheduler; 453 454namespace { 455 456void 457throwingReportHandler(const ::sc_core::sc_report &r, 458 const ::sc_core::sc_actions &) 459{ 460 throw r; 461} 462 463} // anonymous namespace 464 465const ::sc_core::sc_report 466reportifyException() 467{ 468 ::sc_core::sc_report_handler_proc old_handler = 469 ::sc_core::sc_report_handler::get_handler(); 470 ::sc_core::sc_report_handler::set_handler(&throwingReportHandler); 471 472 try { 473 try { 474 // Rethrow the current exception so we can catch it and throw an 475 // sc_report instead if it's not a type we recognize/can handle. 476 throw; 477 } catch (const ::sc_core::sc_report &) { 478 // It's already a sc_report, so nothing to do. 479 throw; 480 } catch (const ::sc_core::sc_unwind_exception &) { 481 panic("Kill/reset exception escaped a Process::run()"); 482 } catch (const std::exception &e) { 483 SC_REPORT_ERROR("uncaught exception", e.what()); 484 } catch (const char *msg) { 485 SC_REPORT_ERROR("uncaught exception", msg); 486 } catch (...) { 487 SC_REPORT_ERROR("uncaught exception", "UNKNOWN EXCEPTION"); 488 } 489 } catch (const ::sc_core::sc_report &r) { 490 ::sc_core::sc_report_handler::set_handler(old_handler); 491 return r; 492 } 493 panic("No exception thrown in reportifyException."); 494} 495 496} // namespace sc_gem5
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