scheduler.cc revision 13186:1ebc6c729311
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 40namespace sc_gem5 41{ 42 43Scheduler::Scheduler() : 44 eq(nullptr), readyEvent(this, false, ReadyPriority), 45 pauseEvent(this, false, PausePriority), 46 stopEvent(this, false, StopPriority), 47 scMain(nullptr), _throwToScMain(nullptr), 48 starvationEvent(this, false, StarvationPriority), 49 _started(false), _stopNow(false), _status(StatusOther), 50 maxTickEvent(this, false, MaxTickPriority), 51 _numCycles(0), _changeStamp(0), _current(nullptr), initDone(false), 52 runOnce(false), readyList(nullptr) 53{} 54 55Scheduler::~Scheduler() 56{ 57 // Clear out everything that belongs to us to make sure nobody tries to 58 // clear themselves out after the scheduler goes away. 59 clear(); 60} 61 62void 63Scheduler::clear() 64{ 65 // Delta notifications. 66 while (!deltas.empty()) 67 deltas.front()->deschedule(); 68 69 // Timed notifications. 70 for (auto &tsp: timeSlots) { 71 TimeSlot *&ts = tsp.second; 72 while (!ts->events.empty()) 73 ts->events.front()->deschedule(); 74 deschedule(ts); 75 } 76 timeSlots.clear(); 77 78 // gem5 events. 79 if (readyEvent.scheduled()) 80 deschedule(&readyEvent); 81 if (pauseEvent.scheduled()) 82 deschedule(&pauseEvent); 83 if (stopEvent.scheduled()) 84 deschedule(&stopEvent); 85 if (starvationEvent.scheduled()) 86 deschedule(&starvationEvent); 87 if (maxTickEvent.scheduled()) 88 deschedule(&maxTickEvent); 89 90 Process *p; 91 while ((p = toFinalize.getNext())) 92 p->popListNode(); 93 while ((p = initList.getNext())) 94 p->popListNode(); 95 while ((p = readyListMethods.getNext())) 96 p->popListNode(); 97 while ((p = readyListThreads.getNext())) 98 p->popListNode(); 99 100 Channel *c; 101 while ((c = updateList.getNext())) 102 c->popListNode(); 103} 104 105void 106Scheduler::initPhase() 107{ 108 for (Process *p = toFinalize.getNext(); p; p = toFinalize.getNext()) { 109 p->finalize(); 110 p->popListNode(); 111 112 if (!p->hasStaticSensitivities() && !p->internal()) { 113 SC_REPORT_WARNING( 114 "(W558) disable() or dont_initialize() called on process " 115 "with no static sensitivity, it will be orphaned", 116 p->name()); 117 } 118 } 119 120 for (Process *p = initList.getNext(); p; p = initList.getNext()) { 121 p->finalize(); 122 p->popListNode(); 123 p->ready(); 124 } 125 126 runUpdate(); 127 runDelta(); 128 129 for (auto ets: eventsToSchedule) 130 eq->schedule(ets.first, ets.second); 131 eventsToSchedule.clear(); 132 133 if (_started) { 134 if (!runToTime && starved()) 135 scheduleStarvationEvent(); 136 kernel->status(::sc_core::SC_RUNNING); 137 } 138 139 initDone = true; 140 141 status(StatusOther); 142} 143 144void 145Scheduler::reg(Process *p) 146{ 147 if (initDone) { 148 // If we're past initialization, finalize static sensitivity. 149 p->finalize(); 150 // Mark the process as ready. 151 p->ready(); 152 } else { 153 // Otherwise, record that this process should be initialized once we 154 // get there. 155 initList.pushLast(p); 156 } 157} 158 159void 160Scheduler::dontInitialize(Process *p) 161{ 162 if (initDone) { 163 // Pop this process off of the ready list. 164 p->popListNode(); 165 } else { 166 // Push this process onto the list of processes which still need 167 // their static sensitivity to be finalized. That implicitly pops it 168 // off the list of processes to be initialized/marked ready. 169 toFinalize.pushLast(p); 170 } 171} 172 173void 174Scheduler::yield() 175{ 176 // Pull a process from the active list. 177 _current = readyList->getNext(); 178 if (!_current) { 179 // There are no more processes, so return control to evaluate. 180 Fiber::primaryFiber()->run(); 181 } else { 182 _current->popListNode(); 183 // Switch to whatever Fiber is supposed to run this process. All 184 // Fibers which aren't running should be parked at this line. 185 _current->fiber()->run(); 186 // If the current process needs to be manually started, start it. 187 if (_current && _current->needsStart()) { 188 _current->needsStart(false); 189 try { 190 _current->run(); 191 } catch (...) { 192 throwToScMain(); 193 } 194 } 195 } 196 if (_current && _current->excWrapper) { 197 // Make sure this isn't a method process. 198 assert(!_current->needsStart()); 199 auto ew = _current->excWrapper; 200 _current->excWrapper = nullptr; 201 ew->throw_it(); 202 } 203} 204 205void 206Scheduler::ready(Process *p) 207{ 208 if (_stopNow) 209 return; 210 211 if (p->procKind() == ::sc_core::SC_METHOD_PROC_) 212 readyListMethods.pushLast(p); 213 else 214 readyListThreads.pushLast(p); 215 216 scheduleReadyEvent(); 217} 218 219void 220Scheduler::resume(Process *p) 221{ 222 if (initDone) 223 ready(p); 224 else 225 initList.pushLast(p); 226} 227 228bool 229listContains(ListNode *list, ListNode *target) 230{ 231 ListNode *n = list->nextListNode; 232 while (n != list) 233 if (n == target) 234 return true; 235 return false; 236} 237 238bool 239Scheduler::suspend(Process *p) 240{ 241 bool was_ready; 242 if (initDone) { 243 // After initialization, the only list we can be on is the ready list. 244 was_ready = (p->nextListNode != nullptr); 245 p->popListNode(); 246 } else { 247 // Check the ready lists to see if we find this process. 248 was_ready = listContains(&readyListMethods, p) || 249 listContains(&readyListThreads, p); 250 if (was_ready) 251 toFinalize.pushLast(p); 252 } 253 return was_ready; 254} 255 256void 257Scheduler::requestUpdate(Channel *c) 258{ 259 updateList.pushLast(c); 260 scheduleReadyEvent(); 261} 262 263void 264Scheduler::scheduleReadyEvent() 265{ 266 // Schedule the evaluate and update phases. 267 if (!readyEvent.scheduled()) { 268 schedule(&readyEvent); 269 if (starvationEvent.scheduled()) 270 deschedule(&starvationEvent); 271 } 272} 273 274void 275Scheduler::scheduleStarvationEvent() 276{ 277 if (!starvationEvent.scheduled()) { 278 schedule(&starvationEvent); 279 if (readyEvent.scheduled()) 280 deschedule(&readyEvent); 281 } 282} 283 284void 285Scheduler::runReady() 286{ 287 bool empty = readyListMethods.empty() && readyListThreads.empty(); 288 lastReadyTick = getCurTick(); 289 290 // The evaluation phase. 291 do { 292 // We run methods and threads in two seperate passes to emulate how 293 // Accellera orders things, but without having to scan through a 294 // unified list to find the next process of the correct type. 295 readyList = &readyListMethods; 296 while (!readyListMethods.empty()) 297 yield(); 298 299 readyList = &readyListThreads; 300 while (!readyListThreads.empty()) 301 yield(); 302 303 // We already know that readyListThreads is empty at this point. 304 } while (!readyListMethods.empty()); 305 306 if (!empty) { 307 _numCycles++; 308 _changeStamp++; 309 } 310 311 if (_stopNow) 312 return; 313 314 runUpdate(); 315 runDelta(); 316 317 if (!runToTime && starved()) 318 scheduleStarvationEvent(); 319 320 if (runOnce) 321 schedulePause(); 322 323 status(StatusOther); 324} 325 326void 327Scheduler::runUpdate() 328{ 329 status(StatusUpdate); 330 331 Channel *channel = updateList.getNext(); 332 while (channel) { 333 channel->popListNode(); 334 channel->update(); 335 channel = updateList.getNext(); 336 } 337} 338 339void 340Scheduler::runDelta() 341{ 342 status(StatusDelta); 343 while (!deltas.empty()) 344 deltas.front()->run(); 345} 346 347void 348Scheduler::pause() 349{ 350 status(StatusPaused); 351 kernel->status(::sc_core::SC_PAUSED); 352 runOnce = false; 353 if (scMain && !scMain->finished()) 354 scMain->run(); 355} 356 357void 358Scheduler::stop() 359{ 360 status(StatusStopped); 361 kernel->stop(); 362 363 clear(); 364 365 runOnce = false; 366 if (scMain && !scMain->finished()) 367 scMain->run(); 368} 369 370void 371Scheduler::start(Tick max_tick, bool run_to_time) 372{ 373 // We should be running from sc_main. Keep track of that Fiber to return 374 // to later. 375 scMain = Fiber::currentFiber(); 376 377 _started = true; 378 status(StatusOther); 379 runToTime = run_to_time; 380 381 maxTick = max_tick; 382 lastReadyTick = getCurTick(); 383 384 if (initDone) { 385 if (!runToTime && starved()) 386 scheduleStarvationEvent(); 387 kernel->status(::sc_core::SC_RUNNING); 388 } 389 390 schedule(&maxTickEvent, maxTick); 391 392 // Return to gem5 to let it run events, etc. 393 Fiber::primaryFiber()->run(); 394 395 if (pauseEvent.scheduled()) 396 deschedule(&pauseEvent); 397 if (stopEvent.scheduled()) 398 deschedule(&stopEvent); 399 if (maxTickEvent.scheduled()) 400 deschedule(&maxTickEvent); 401 if (starvationEvent.scheduled()) 402 deschedule(&starvationEvent); 403 404 if (_throwToScMain) { 405 const ::sc_core::sc_report *to_throw = _throwToScMain; 406 _throwToScMain = nullptr; 407 throw *to_throw; 408 } 409} 410 411void 412Scheduler::oneCycle() 413{ 414 runOnce = true; 415 scheduleReadyEvent(); 416 start(::MaxTick, false); 417} 418 419void 420Scheduler::schedulePause() 421{ 422 if (pauseEvent.scheduled()) 423 return; 424 425 schedule(&pauseEvent); 426} 427 428void 429Scheduler::throwToScMain(const ::sc_core::sc_report *r) 430{ 431 if (!r) 432 r = reportifyException(); 433 _throwToScMain = r; 434 scMain->run(); 435} 436 437void 438Scheduler::scheduleStop(bool finish_delta) 439{ 440 if (stopEvent.scheduled()) 441 return; 442 443 if (!finish_delta) { 444 _stopNow = true; 445 // If we're not supposed to finish the delta cycle, flush all 446 // pending activity. 447 clear(); 448 } 449 schedule(&stopEvent); 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 497