src/sim/eventq.cc

   1 /*
   2  * Copyright (c) 2000-2005 The Regents of The University of Michigan
   3  * Copyright (c) 2008 The Hewlett-Packard Development Company
   4  * Copyright (c) 2013 Advanced Micro Devices, Inc.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are
   9  * met: redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer;
  11  * redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution;
  14  * neither the name of the copyright holders nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * Authors: Steve Reinhardt
  31  *          Nathan Binkert
  32  *          Steve Raasch
  33  */
  34
  35 #include <cassert>
  36 #include <iostream>
  37 #include <string>
  38 #include <vector>
  39
  40 #include "base/hashmap.hh"
  41 #include "base/misc.hh"
  42 #include "base/trace.hh"
  43 #include "cpu/smt.hh"
  44 #include "debug/Config.hh"
  45 #include "sim/core.hh"
  46 #include "sim/eventq_impl.hh"
  47
  48 using namespace std;
  49
  50 Tick simQuantum = 0;
  51
  52 //
  53 // Main Event Queues
  54 //
  55 // Events on these queues are processed at the *beginning* of each
  56 // cycle, before the pipeline simulation is performed.
  57 //
  58 uint32_t numMainEventQueues = 0;
  59 vector<EventQueue *> mainEventQueue;
  60 __thread EventQueue *_curEventQueue = NULL;
  61 bool inParallelMode = false;
  62
  63 EventQueue *
  64 getEventQueue(uint32_t index)
  65 {
  66     while (numMainEventQueues <= index) {
  67         numMainEventQueues++;
  68         mainEventQueue.push_back(
  69             new EventQueue(csprintf("MainEventQueue-%d", index)));
  70     }
  71
  72     return mainEventQueue[index];
  73 }
  74
  75 #ifndef NDEBUG
  76 Counter Event::instanceCounter = 0;
  77 #endif
  78
  79 Event::~Event()
  80 {
  81     assert(!scheduled());
  82     flags = 0;
  83 }
  84
  85 const std::string
  86 Event::name() const
  87 {
  88 #ifndef NDEBUG
  89     return csprintf("Event_%d", instance);
  90 #else
  91     return csprintf("Event_%x", (uintptr_t)this);
  92 #endif
  93 }
  94
  95
  96 Event *
  97 Event::insertBefore(Event *event, Event *curr)
  98 {
  99     // Either way, event will be the top element in the 'in bin' list
 100     // which is the pointer we need in order to look into the list, so
 101     // we need to insert that into the bin list.
 102     if (!curr || *event < *curr) {
 103         // Insert the event before the current list since it is in the future.
 104         event->nextBin = curr;
 105         event->nextInBin = NULL;
 106     } else {
 107         // Since we're on the correct list, we need to point to the next list
 108         event->nextBin = curr->nextBin;  // curr->nextBin can now become stale
 109
 110         // Insert event at the top of the stack
 111         event->nextInBin = curr;
 112     }
 113
 114     return event;
 115 }
 116
 117 void
 118 EventQueue::insert(Event *event)
 119 {
 120     // Deal with the head case
 121     if (!head || *event <= *head) {
 122         head = Event::insertBefore(event, head);
 123         return;
 124     }
 125
 126     // Figure out either which 'in bin' list we are on, or where a new list
 127     // needs to be inserted
 128     Event *prev = head;
 129     Event *curr = head->nextBin;
 130     while (curr && *curr < *event) {
 131         prev = curr;
 132         curr = curr->nextBin;
 133     }
 134
 135     // Note: this operation may render all nextBin pointers on the
 136     // prev 'in bin' list stale (except for the top one)
 137     prev->nextBin = Event::insertBefore(event, curr);
 138 }
 139
 140 Event *
 141 Event::removeItem(Event *event, Event *top)
 142 {
 143     Event *curr = top;
 144     Event *next = top->nextInBin;
 145
 146     // if we removed the top item, we need to handle things specially
 147     // and just remove the top item, fixing up the next bin pointer of
 148     // the new top item
 149     if (event == top) {
 150         if (!next)
 151             return top->nextBin;
 152         next->nextBin = top->nextBin;
 153         return next;
 154     }
 155
 156     // Since we already checked the current element, we're going to
 157     // keep checking event against the next element.
 158     while (event != next) {
 159         if (!next)
 160             panic("event not found!");
 161
 162         curr = next;
 163         next = next->nextInBin;
 164     }
 165
 166     // remove next from the 'in bin' list since it's what we're looking for
 167     curr->nextInBin = next->nextInBin;
 168     return top;
 169 }
 170
 171 void
 172 EventQueue::remove(Event *event)
 173 {
 174     if (head == NULL)
 175         panic("event not found!");
 176
 177     assert(event->queue == this);
 178
 179     // deal with an event on the head's 'in bin' list (event has the same
 180     // time as the head)
 181     if (*head == *event) {
 182         head = Event::removeItem(event, head);
 183         return;
 184     }
 185
 186     // Find the 'in bin' list that this event belongs on
 187     Event *prev = head;
 188     Event *curr = head->nextBin;
 189     while (curr && *curr < *event) {
 190         prev = curr;
 191         curr = curr->nextBin;
 192     }
 193
 194     if (!curr || *curr != *event)
 195         panic("event not found!");
 196
 197     // curr points to the top item of the the correct 'in bin' list, when
 198     // we remove an item, it returns the new top item (which may be
 199     // unchanged)
 200     prev->nextBin = Event::removeItem(event, curr);
 201 }
 202
 203 Event *
 204 EventQueue::serviceOne()
 205 {
 206     std::lock_guard<EventQueue> lock(*this);
 207     Event *event = head;
 208     Event *next = head->nextInBin;
 209     event->flags.clear(Event::Scheduled);
 210
 211     if (next) {
 212         // update the next bin pointer since it could be stale
 213         next->nextBin = head->nextBin;
 214
 215         // pop the stack
 216         head = next;
 217     } else {
 218         // this was the only element on the 'in bin' list, so get rid of
 219         // the 'in bin' list and point to the next bin list
 220         head = head->nextBin;
 221     }
 222
 223     // handle action
 224     if (!event->squashed()) {
 225         // forward current cycle to the time when this event occurs.
 226         setCurTick(event->when());
 227
 228         event->process();
 229         if (event->isExitEvent()) {
 230             assert(!event->flags.isSet(Event::AutoDelete) ||
 231                    !event->flags.isSet(Event::IsMainQueue)); // would be silly
 232             return event;
 233         }
 234     } else {
 235         event->flags.clear(Event::Squashed);
 236     }
 237
 238     if (event->flags.isSet(Event::AutoDelete) && !event->scheduled())
 239         delete event;
 240
 241     return NULL;
 242 }
 243
 244 void
 245 Event::serialize(std::ostream &os)
 246 {
 247     SERIALIZE_SCALAR(_when);
 248     SERIALIZE_SCALAR(_priority);
 249     short _flags = flags;
 250     SERIALIZE_SCALAR(_flags);
 251 }
 252
 253 void
 254 Event::unserialize(Checkpoint *cp, const string &section)
 255 {
 256 }
 257
 258 void
 259 Event::unserialize(Checkpoint *cp, const string &section, EventQueue *eventq)
 260 {
 261     if (scheduled())
 262         eventq->deschedule(this);
 263
 264     UNSERIALIZE_SCALAR(_when);
 265     UNSERIALIZE_SCALAR(_priority);
 266
 267     short _flags;
 268     UNSERIALIZE_SCALAR(_flags);
 269
 270     // Old checkpoints had no concept of the Initialized flag
 271     // so restoring from old checkpoints always fail.
 272     // Events are initialized on construction but original code
 273     // "flags = _flags" would just overwrite the initialization.
 274     // So, read in the checkpoint flags, but then set the Initialized
 275     // flag on top of it in order to avoid failures.
 276     assert(initialized());
 277     flags = _flags;
 278     flags.set(Initialized);
 279
 280     // need to see if original event was in a scheduled, unsquashed
 281     // state, but don't want to restore those flags in the current
 282     // object itself (since they aren't immediately true)
 283     bool wasScheduled = flags.isSet(Scheduled) && !flags.isSet(Squashed);
 284     flags.clear(Squashed | Scheduled);
 285
 286     if (wasScheduled) {
 287         DPRINTF(Config, "rescheduling at %d\n", _when);
 288         eventq->schedule(this, _when);
 289     }
 290 }
 291
 292 void
 293 EventQueue::serialize(ostream &os)
 294 {
 295     std::list<Event *> eventPtrs;
 296
 297     int numEvents = 0;
 298     Event *nextBin = head;
 299     while (nextBin) {
 300         Event *nextInBin = nextBin;
 301
 302         while (nextInBin) {
 303             if (nextInBin->flags.isSet(Event::AutoSerialize)) {
 304                 eventPtrs.push_back(nextInBin);
 305                 paramOut(os, csprintf("event%d", numEvents++),
 306                          nextInBin->name());
 307             }
 308             nextInBin = nextInBin->nextInBin;
 309         }
 310
 311         nextBin = nextBin->nextBin;
 312     }
 313
 314     SERIALIZE_SCALAR(numEvents);
 315
 316     for (std::list<Event *>::iterator it = eventPtrs.begin();
 317          it != eventPtrs.end(); ++it) {
 318         (*it)->nameOut(os);
 319         (*it)->serialize(os);
 320     }
 321 }
 322
 323 void
 324 EventQueue::unserialize(Checkpoint *cp, const std::string &section)
 325 {
 326     int numEvents;
 327     UNSERIALIZE_SCALAR(numEvents);
 328
 329     std::string eventName;
 330     for (int i = 0; i < numEvents; i++) {
 331         // get the pointer value associated with the event
 332         paramIn(cp, section, csprintf("event%d", i), eventName);
 333
 334         // create the event based on its pointer value
 335         Serializable::create(cp, eventName);
 336     }
 337 }
 338
 339 void
 340 EventQueue::dump() const
 341 {
 342     cprintf("============================================================\n");
 343     cprintf("EventQueue Dump  (cycle %d)\n", curTick());
 344     cprintf("------------------------------------------------------------\n");
 345
 346     if (empty())
 347         cprintf("<No Events>\n");
 348     else {
 349         Event *nextBin = head;
 350         while (nextBin) {
 351             Event *nextInBin = nextBin;
 352             while (nextInBin) {
 353                 nextInBin->dump();
 354                 nextInBin = nextInBin->nextInBin;
 355             }
 356
 357             nextBin = nextBin->nextBin;
 358         }
 359     }
 360
 361     cprintf("============================================================\n");
 362 }
 363
 364 bool
 365 EventQueue::debugVerify() const
 366 {
 367     m5::hash_map<long, bool> map;
 368
 369     Tick time = 0;
 370     short priority = 0;
 371
 372     Event *nextBin = head;
 373     while (nextBin) {
 374         Event *nextInBin = nextBin;
 375         while (nextInBin) {
 376             if (nextInBin->when() < time) {
 377                 cprintf("time goes backwards!");
 378                 nextInBin->dump();
 379                 return false;
 380             } else if (nextInBin->when() == time &&
 381                        nextInBin->priority() < priority) {
 382                 cprintf("priority inverted!");
 383                 nextInBin->dump();
 384                 return false;
 385             }
 386
 387             if (map[reinterpret_cast<long>(nextInBin)]) {
 388                 cprintf("Node already seen");
 389                 nextInBin->dump();
 390                 return false;
 391             }
 392             map[reinterpret_cast<long>(nextInBin)] = true;
 393
 394             time = nextInBin->when();
 395             priority = nextInBin->priority();
 396
 397             nextInBin = nextInBin->nextInBin;
 398         }
 399
 400         nextBin = nextBin->nextBin;
 401     }
 402
 403     return true;
 404 }
 405
 406 Event*
 407 EventQueue::replaceHead(Event* s)
 408 {
 409     Event* t = head;
 410     head = s;
 411     return t;
 412 }
 413
 414 void
 415 dumpMainQueue()
 416 {
 417     for (uint32_t i = 0; i < numMainEventQueues; ++i) {
 418         mainEventQueue[i]->dump();
 419     }
 420 }
 421
 422
 423 const char *
 424 Event::description() const
 425 {
 426     return "generic";
 427 }
 428
 429 void
 430 Event::trace(const char *action)
 431 {
 432     // This DPRINTF is unconditional because calls to this function
 433     // are protected by an 'if (DTRACE(Event))' in the inlined Event
 434     // methods.
 435     //
 436     // This is just a default implementation for derived classes where
 437     // it's not worth doing anything special.  If you want to put a
 438     // more informative message in the trace, override this method on
 439     // the particular subclass where you have the information that
 440     // needs to be printed.
 441     DPRINTFN("%s event %s @ %d\n", description(), action, when());
 442 }
 443
 444 void
 445 Event::dump() const
 446 {
 447     cprintf("Event %s (%s)\n", name(), description());
 448     cprintf("Flags: %#x\n", flags);
 449 #ifdef EVENTQ_DEBUG
 450     cprintf("Created: %d\n", whenCreated);
 451 #endif
 452     if (scheduled()) {
 453 #ifdef EVENTQ_DEBUG
 454         cprintf("Scheduled at  %d\n", whenScheduled);
 455 #endif
 456         cprintf("Scheduled for %d, priority %d\n", when(), _priority);
 457     } else {
 458         cprintf("Not Scheduled\n");
 459     }
 460 }
 461
 462 EventQueue::EventQueue(const string &n)
 463     : objName(n), head(NULL), _curTick(0),
 464     async_queue_mutex(new std::mutex())
 465 {
 466 }
 467
 468 void
 469 EventQueue::asyncInsert(Event *event)
 470 {
 471     async_queue_mutex->lock();
 472     async_queue.push_back(event);
 473     async_queue_mutex->unlock();
 474 }
 475
 476 void
 477 EventQueue::handleAsyncInsertions()
 478 {
 479     assert(this == curEventQueue());
 480     async_queue_mutex->lock();
 481
 482     while (!async_queue.empty()) {
 483         insert(async_queue.front());
 484         async_queue.pop_front();
 485     }
 486
 487     async_queue_mutex->unlock();
 488 }