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16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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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
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28 * Authors: Steve Reinhardt
33 * EventQueue interfaces
36 #ifndef __SIM_EVENTQ_HH__
37 #define __SIM_EVENTQ_HH__
45 #include "base/flags.hh"
46 #include "base/misc.hh"
47 #include "base/trace.hh"
48 #include "base/types.hh"
49 #include "debug/Event.hh"
50 #include "sim/serialize.hh"
52 class EventQueue; // forward declaration
54 extern EventQueue mainEventQueue;
57 * An item on an event queue. The action caused by a given
58 * event is specified by deriving a subclass and overriding the
59 * process() member function.
61 * Caution, the order of members is chosen to maximize data packing.
63 class Event : public Serializable
65 friend class EventQueue;
68 typedef unsigned short FlagsType;
69 typedef ::Flags<FlagsType> Flags;
71 static const FlagsType PublicRead = 0x003f; // public readable flags
72 static const FlagsType PublicWrite = 0x001d; // public writable flags
73 static const FlagsType Squashed = 0x0001; // has been squashed
74 static const FlagsType Scheduled = 0x0002; // has been scheduled
75 static const FlagsType AutoDelete = 0x0004; // delete after dispatch
76 static const FlagsType AutoSerialize = 0x0008; // must be serialized
77 static const FlagsType IsExitEvent = 0x0010; // special exit event
78 static const FlagsType IsMainQueue = 0x0020; // on main event queue
79 static const FlagsType Initialized = 0x7a40; // somewhat random bits
80 static const FlagsType InitMask = 0xffc0; // mask for init bits
85 return this && (flags & InitMask) == Initialized;
89 typedef int8_t Priority;
92 // The event queue is now a linked list of linked lists. The
93 // 'nextBin' pointer is to find the bin, where a bin is defined as
94 // when+priority. All events in the same bin will be stored in a
95 // second linked list (a stack) maintained by the 'nextInBin'
96 // pointer. The list will be accessed in LIFO order. The end
97 // result is that the insert/removal in 'nextBin' is
98 // linear/constant, and the lookup/removal in 'nextInBin' is
99 // constant/constant. Hopefully this is a significant improvement
100 // over the current fully linear insertion.
104 static Event *insertBefore(Event *event, Event *curr);
105 static Event *removeItem(Event *event, Event *last);
107 Tick _when; //!< timestamp when event should be processed
108 Priority _priority; //!< event priority
112 /// Global counter to generate unique IDs for Event instances
113 static Counter instanceCounter;
115 /// This event's unique ID. We can also use pointer values for
116 /// this but they're not consistent across runs making debugging
117 /// more difficult. Thus we use a global counter value when
121 /// queue to which this event belongs (though it may or may not be
122 /// scheduled on this queue yet)
127 Tick whenCreated; //!< time created
128 Tick whenScheduled; //!< time scheduled
132 setWhen(Tick when, EventQueue *q)
139 whenScheduled = curTick();
144 /// Accessor for flags.
148 return flags & PublicRead;
152 isFlagSet(Flags _flags) const
154 assert(_flags.noneSet(~PublicRead));
155 return flags.isSet(_flags);
158 /// Accessor for flags.
160 setFlags(Flags _flags)
162 assert(_flags.noneSet(~PublicWrite));
167 clearFlags(Flags _flags)
169 assert(_flags.noneSet(~PublicWrite));
176 flags.clear(PublicWrite);
179 // This function isn't really useful if TRACING_ON is not defined
180 virtual void trace(const char *action); //!< trace event activity
183 /// Event priorities, to provide tie-breakers for events scheduled
184 /// at the same cycle. Most events are scheduled at the default
185 /// priority; these values are used to control events that need to
186 /// be ordered within a cycle.
189 static const Priority Minimum_Pri = SCHAR_MIN;
191 /// If we enable tracing on a particular cycle, do that as the
192 /// very first thing so we don't miss any of the events on
193 /// that cycle (even if we enter the debugger).
194 static const Priority Trace_Enable_Pri = -101;
196 /// Breakpoints should happen before anything else (except
197 /// enabling trace output), so we don't miss any action when
199 static const Priority Debug_Break_Pri = -100;
201 /// CPU switches schedule the new CPU's tick event for the
202 /// same cycle (after unscheduling the old CPU's tick event).
203 /// The switch needs to come before any tick events to make
204 /// sure we don't tick both CPUs in the same cycle.
205 static const Priority CPU_Switch_Pri = -31;
207 /// For some reason "delayed" inter-cluster writebacks are
208 /// scheduled before regular writebacks (which have default
209 /// priority). Steve?
210 static const Priority Delayed_Writeback_Pri = -1;
212 /// Default is zero for historical reasons.
213 static const Priority Default_Pri = 0;
215 /// Serailization needs to occur before tick events also, so
216 /// that a serialize/unserialize is identical to an on-line
218 static const Priority Serialize_Pri = 32;
220 /// CPU ticks must come after other associated CPU events
221 /// (such as writebacks).
222 static const Priority CPU_Tick_Pri = 50;
224 /// Statistics events (dump, reset, etc.) come after
225 /// everything else, but before exit.
226 static const Priority Stat_Event_Pri = 90;
228 /// Progress events come at the end.
229 static const Priority Progress_Event_Pri = 95;
231 /// If we want to exit on this cycle, it's the very last thing
233 static const Priority Sim_Exit_Pri = 100;
236 static const Priority Maximum_Pri = SCHAR_MAX;
240 * @param queue that the event gets scheduled on
242 Event(Priority p = Default_Pri, Flags f = 0)
243 : nextBin(NULL), nextInBin(NULL), _priority(p),
244 flags(Initialized | f)
246 assert(f.noneSet(~PublicWrite));
248 instance = ++instanceCounter;
252 whenCreated = curTick();
258 virtual const std::string name() const;
260 /// Return a C string describing the event. This string should
261 /// *not* be dynamically allocated; just a const char array
262 /// describing the event class.
263 virtual const char *description() const;
265 /// Dump the current event data
270 * This member function is invoked when the event is processed
271 * (occurs). There is no default implementation; each subclass
272 * must provide its own implementation. The event is not
273 * automatically deleted after it is processed (to allow for
274 * statically allocated event objects).
276 * If the AutoDestroy flag is set, the object is deleted once it
279 virtual void process() = 0;
281 /// Determine if the current event is scheduled
282 bool scheduled() const { return flags.isSet(Scheduled); }
284 /// Squash the current event
285 void squash() { flags.set(Squashed); }
287 /// Check whether the event is squashed
288 bool squashed() const { return flags.isSet(Squashed); }
290 /// See if this is a SimExitEvent (without resorting to RTTI)
291 bool isExitEvent() const { return flags.isSet(IsExitEvent); }
293 /// Get the time that the event is scheduled
294 Tick when() const { return _when; }
296 /// Get the event priority
297 Priority priority() const { return _priority; }
300 struct priority_compare
301 : public std::binary_function<Event *, Event *, bool>
304 operator()(const Event *l, const Event *r) const
306 return l->when() >= r->when() || l->priority() >= r->priority();
310 virtual void serialize(std::ostream &os);
311 virtual void unserialize(Checkpoint *cp, const std::string §ion);
317 operator<(const Event &l, const Event &r)
319 return l.when() < r.when() ||
320 (l.when() == r.when() && l.priority() < r.priority());
324 operator>(const Event &l, const Event &r)
326 return l.when() > r.when() ||
327 (l.when() == r.when() && l.priority() > r.priority());
331 operator<=(const Event &l, const Event &r)
333 return l.when() < r.when() ||
334 (l.when() == r.when() && l.priority() <= r.priority());
337 operator>=(const Event &l, const Event &r)
339 return l.when() > r.when() ||
340 (l.when() == r.when() && l.priority() >= r.priority());
344 operator==(const Event &l, const Event &r)
346 return l.when() == r.when() && l.priority() == r.priority();
350 operator!=(const Event &l, const Event &r)
352 return l.when() != r.when() || l.priority() != r.priority();
357 * Queue of events sorted in time order
359 class EventQueue : public Serializable
365 void insert(Event *event);
366 void remove(Event *event);
368 EventQueue(const EventQueue &);
369 const EventQueue &operator=(const EventQueue &);
372 EventQueue(const std::string &n);
374 virtual const std::string name() const { return objName; }
376 // schedule the given event on this queue
377 void schedule(Event *event, Tick when);
378 void deschedule(Event *event);
379 void reschedule(Event *event, Tick when, bool always = false);
381 Tick nextTick() const { return head->when(); }
384 // process all events up to the given timestamp. we inline a
385 // quick test to see if there are any events to process; if so,
386 // call the internal out-of-line version to process them all.
388 serviceEvents(Tick when)
391 if (nextTick() > when)
395 * @todo this assert is a good bug catcher. I need to
396 * make it true again.
398 //assert(head->when() >= when && "event scheduled in the past");
403 // return true if no events are queued
404 bool empty() const { return head == NULL; }
408 bool debugVerify() const;
411 * function for replacing the head of the event queue, so that a
412 * different set of events can run without disturbing events that have
413 * already been scheduled. Already scheduled events can be processed
414 * by replacing the original head back.
415 * USING THIS FUNCTION CAN BE DANGEROUS TO THE HEALTH OF THE SIMULATOR.
416 * NOT RECOMMENDED FOR USE.
418 Event* replaceHead(Event* s);
421 virtual void serialize(std::ostream &os);
422 virtual void unserialize(Checkpoint *cp, const std::string §ion);
430 /** A pointer to this object's event queue */
434 EventManager(EventManager &em) : eventq(em.eventq) {}
435 EventManager(EventManager *em) : eventq(em ? em->eventq : NULL) {}
436 EventManager(EventQueue *eq) : eventq(eq) {}
445 schedule(Event &event, Tick when)
447 eventq->schedule(&event, when);
451 deschedule(Event &event)
453 eventq->deschedule(&event);
457 reschedule(Event &event, Tick when, bool always = false)
459 eventq->reschedule(&event, when, always);
463 schedule(Event *event, Tick when)
465 eventq->schedule(event, when);
469 deschedule(Event *event)
471 eventq->deschedule(event);
475 reschedule(Event *event, Tick when, bool always = false)
477 eventq->reschedule(event, when, always);
482 EventQueue::schedule(Event *event, Tick when)
484 // Typecasting Tick->Utick here since gcc
485 // complains about signed overflow
486 assert((UTick)when >= (UTick)curTick());
487 assert(!event->scheduled());
488 assert(event->initialized());
490 event->setWhen(when, this);
492 event->flags.set(Event::Scheduled);
493 if (this == &mainEventQueue)
494 event->flags.set(Event::IsMainQueue);
496 event->flags.clear(Event::IsMainQueue);
499 event->trace("scheduled");
503 EventQueue::deschedule(Event *event)
505 assert(event->scheduled());
506 assert(event->initialized());
510 event->flags.clear(Event::Squashed);
511 event->flags.clear(Event::Scheduled);
514 event->trace("descheduled");
516 if (event->flags.isSet(Event::AutoDelete))
521 EventQueue::reschedule(Event *event, Tick when, bool always)
523 // Typecasting Tick->Utick here since gcc
524 // complains about signed overflow
525 assert((UTick)when >= (UTick)curTick());
526 assert(always || event->scheduled());
527 assert(event->initialized());
529 if (event->scheduled())
532 event->setWhen(when, this);
534 event->flags.clear(Event::Squashed);
535 event->flags.set(Event::Scheduled);
536 if (this == &mainEventQueue)
537 event->flags.set(Event::IsMainQueue);
539 event->flags.clear(Event::IsMainQueue);
542 event->trace("rescheduled");
545 template <class T, void (T::* F)()>
547 DelayFunction(EventQueue *eventq, Tick when, T *object)
549 class DelayEvent : public Event
556 : Event(Default_Pri, AutoDelete), object(o)
558 void process() { (object->*F)(); }
559 const char *description() const { return "delay"; }
562 eventq->schedule(new DelayEvent(object), when);
565 template <class T, void (T::* F)()>
566 class EventWrapper : public Event
572 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
573 : Event(p), object(obj)
576 setFlags(AutoDelete);
579 EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
580 : Event(p), object(&obj)
583 setFlags(AutoDelete);
586 void process() { (object->*F)(); }
591 return object->name() + ".wrapped_event";
594 const char *description() const { return "EventWrapped"; }
598 #endif // __SIM_EVENTQ_HH__