sim/eventq.hh

   1 /*
   2  * Copyright (c) 2003 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /* @file
  30  * EventQueue interfaces
  31  */
  32
  33 #ifndef __EVENTQ_HH__
  34 #define __EVENTQ_HH__
  35
  36 #include <assert.h>
  37
  38 #include <algorithm>
  39 #include <map>
  40 #include <string>
  41 #include <vector>
  42
  43 #include "sim/host.hh"  // for Tick
  44
  45 #include "base/fast_alloc.hh"
  46 #include "sim/serialize.hh"
  47 #include "base/trace.hh"
  48
  49 class EventQueue;       // forward declaration
  50
  51 /*
  52  * An item on an event queue.  The action caused by a given
  53  * event is specified by deriving a subclass and overriding the
  54  * process() member function.
  55  */
  56 class Event : public Serializeable, public FastAlloc
  57 {
  58     friend class EventQueue;
  59
  60   private:
  61     /// queue to which this event belongs (though it may or may not be
  62     /// scheduled on this queue yet)
  63     EventQueue *queue;
  64
  65     Event *next;
  66
  67     Tick _when; //!< timestamp when event should be processed
  68     int _priority;      //!< event priority
  69     char _flags;
  70
  71   protected:
  72     enum Flags {
  73         None = 0x0,
  74         Squashed = 0x1,
  75         Scheduled = 0x2,
  76         AutoDelete = 0x4,
  77         AutoSerialize = 0x8
  78     };
  79
  80     bool getFlags(Flags f) const { return (_flags & f) == f; }
  81     void setFlags(Flags f) { _flags |= f; }
  82     void clearFlags(Flags f) { _flags &= ~f; }
  83
  84   protected:
  85     EventQueue *theQueue() const { return queue; }
  86
  87 #if TRACING_ON
  88     Tick when_created;  //!< Keep track of creation time For debugging
  89     Tick when_scheduled;        //!< Keep track of creation time For debugging
  90
  91     virtual void trace(const char *action);     //!< trace event activity
  92 #else
  93     void trace(const char *) {}
  94 #endif
  95
  96     unsigned annotated_value;
  97
  98   public:
  99
 100     static const std::string defaultName;
 101
 102     /*
 103      * Event constructor
 104      * @param queue that the event gets scheduled on
 105      */
 106     Event(EventQueue *q, int p = 0)
 107         : queue(q), next(NULL), _priority(p), _flags(None),
 108 #if TRACING_ON
 109           when_created(curTick), when_scheduled(0),
 110 #endif
 111           annotated_value(0)
 112     {
 113     }
 114
 115     ~Event() {}
 116
 117     virtual std::string name() const {
 118         return csprintf("%s_%x", defaultName, (uintptr_t)this);
 119     }
 120
 121     /// Determine if the current event is scheduled
 122     bool scheduled() const { return getFlags(Scheduled); }
 123
 124     /// Schedule the event with the current priority or default priority
 125     void schedule(Tick t);
 126
 127     /// Schedule the event with a specific priority
 128     void schedule(Tick t, int priority);
 129
 130     /// Reschedule the event with the current priority
 131     void reschedule(Tick t);
 132
 133     /// Reschedule the event with a specific priority
 134     void reschedule(Tick t, int priority);
 135
 136     /// Remove the event from the current schedule
 137     void deschedule();
 138
 139     /// Return a C string describing the event.  This string should
 140     /// *not* be dynamically allocated; just a const char array
 141     /// describing the event class.
 142     virtual const char *description();
 143
 144     /// Dump the current event data
 145     void dump();
 146
 147     /*
 148      * This member function is invoked when the event is processed
 149      * (occurs).  There is no default implementation; each subclass
 150      * must provide its own implementation.  The event is not
 151      * automatically deleted after it is processed (to allow for
 152      * statically allocated event objects).
 153      *
 154      * If the AutoDestroy flag is set, the object is deleted once it
 155      * is processed.
 156      */
 157     virtual void process() = 0;
 158
 159     void annotate(unsigned value) { annotated_value = value; };
 160     unsigned annotation() { return annotated_value; }
 161
 162     /// Squash the current event
 163     void squash() { setFlags(Squashed); }
 164
 165     /// Check whether the event is squashed
 166     bool squashed() { return getFlags(Squashed); }
 167
 168     /// Get the time that the event is scheduled
 169     Tick when() const { return _when; }
 170
 171     /// Get the event priority
 172     int priority() const { return _priority; }
 173
 174     struct priority_compare :
 175     public std::binary_function<Event *, Event *, bool>
 176     {
 177         bool operator()(const Event *l, const Event *r) const {
 178             return l->when() >= r->when() || l->priority() >= r->priority();
 179         }
 180     };
 181
 182     virtual void serialize(std::ostream &os);
 183     virtual void unserialize(Checkpoint *cp, const std::string &section);
 184 };
 185
 186 template <class T, void (T::* F)()>
 187 void
 188 DelayFunction(Tick when, T *object)
 189 {
 190     class DelayEvent : public Event
 191     {
 192       private:
 193         T *object;
 194
 195       public:
 196         DelayEvent(Tick when, T *o)
 197             : Event(&mainEventQueue), object(o)
 198             { setFlags(AutoDestroy); schedule(when); }
 199         void process() { (object->*F)(); }
 200         const char *description() { return "delay"; }
 201     };
 202
 203     new DelayEvent(when, object);
 204 }
 205
 206 /*
 207  * Queue of events sorted in time order
 208  */
 209 class EventQueue : public Serializeable
 210 {
 211   protected:
 212     std::string objName;
 213
 214   private:
 215     Event *head;
 216
 217     void insert(Event *event);
 218     void remove(Event *event);
 219
 220   public:
 221
 222     // constructor
 223     EventQueue(const std::string &n)
 224         : objName(n), head(NULL)
 225     {}
 226
 227     virtual std::string name() const { return objName; }
 228
 229     // schedule the given event on this queue
 230     void schedule(Event *ev);
 231     void deschedule(Event *ev);
 232     void reschedule(Event *ev);
 233
 234     Tick nextTick() { return head->when(); }
 235     void serviceOne();
 236
 237     // process all events up to the given timestamp.  we inline a
 238     // quick test to see if there are any events to process; if so,
 239     // call the internal out-of-line version to process them all.
 240     void serviceEvents(Tick when) {
 241         while (!empty()) {
 242             if (nextTick() > when)
 243                 break;
 244
 245             assert(head->when() >= when && "event scheduled in the past");
 246             serviceOne();
 247         }
 248     }
 249
 250     // default: process all events up to 'now' (curTick)
 251     void serviceEvents() { serviceEvents(curTick); }
 252
 253     // return true if no events are queued
 254     bool empty() { return head == NULL; }
 255
 256     void dump();
 257
 258     Tick nextEventTime() { return empty() ? curTick : head->when(); }
 259
 260     virtual void serialize(std::ostream &os);
 261     virtual void unserialize(Checkpoint *cp, const std::string &section);
 262 };
 263
 264
 265 //////////////////////
 266 //
 267 // inline functions
 268 //
 269 // can't put these inside declaration due to circular dependence
 270 // between Event and EventQueue classes.
 271 //
 272 //////////////////////
 273
 274 // schedule at specified time (place on event queue specified via
 275 // constructor)
 276 inline void
 277 Event::schedule(Tick t)
 278 {
 279     assert(!scheduled());
 280     setFlags(Scheduled);
 281 #if TRACING_ON
 282     when_scheduled = curTick;
 283 #endif
 284     _when = t;
 285     queue->schedule(this);
 286 }
 287
 288 inline void
 289 Event::schedule(Tick t, int p)
 290 {
 291     _priority = p;
 292     schedule(t);
 293 }
 294
 295 inline void
 296 Event::deschedule()
 297 {
 298     assert(scheduled());
 299
 300     clearFlags(Squashed);
 301     clearFlags(Scheduled);
 302     queue->deschedule(this);
 303 }
 304
 305 inline void
 306 Event::reschedule(Tick t)
 307 {
 308     assert(scheduled());
 309     clearFlags(Squashed);
 310
 311 #if TRACING_ON
 312     when_scheduled = curTick;
 313 #endif
 314     _when = t;
 315     queue->reschedule(this);
 316 }
 317
 318 inline void
 319 Event::reschedule(Tick t, int p)
 320 {
 321     _priority = p;
 322     reschedule(t);
 323 }
 324
 325 inline void
 326 EventQueue::schedule(Event *event)
 327 {
 328     insert(event);
 329     if (DTRACE(Event))
 330         event->trace("scheduled");
 331 }
 332
 333 inline void
 334 EventQueue::deschedule(Event *event)
 335 {
 336     remove(event);
 337     if (DTRACE(Event))
 338         event->trace("descheduled");
 339 }
 340
 341 inline void
 342 EventQueue::reschedule(Event *event)
 343 {
 344     remove(event);
 345     insert(event);
 346     if (DTRACE(Event))
 347         event->trace("rescheduled");
 348 }
 349
 350
 351 //////////////////////
 352 //
 353 // Main Event Queue
 354 //
 355 // Events on this queue are processed at the *beginning* of each
 356 // cycle, before the pipeline simulation is performed.
 357 //
 358 // defined in eventq.cc
 359 //
 360 //////////////////////
 361 extern EventQueue mainEventQueue;
 362
 363 #endif // __EVENTQ_HH__