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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,
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28 * Authors: Steve Reinhardt
33 * EventQueue interfaces
36 #ifndef __SIM_EVENTQ_HH__
37 #define __SIM_EVENTQ_HH__
46 #include "base/fast_alloc.hh"
47 #include "base/flags.hh"
48 #include "base/misc.hh"
49 #include "base/trace.hh"
50 #include "sim/serialize.hh"
51 #include "sim/host.hh"
53 class EventQueue; // forward declaration
55 extern EventQueue mainEventQueue;
58 * An item on an event queue. The action caused by a given
59 * event is specified by deriving a subclass and overriding the
60 * process() member function.
62 * Caution, the order of members is chosen to maximize data packing.
64 class Event : public Serializable, public FastAlloc
66 friend class EventQueue;
69 typedef short FlagsType;
70 typedef ::Flags<FlagsType> Flags;
72 static const FlagsType PublicRead = 0x003f;
73 static const FlagsType PublicWrite = 0x001d;
74 static const FlagsType Squashed = 0x0001;
75 static const FlagsType Scheduled = 0x0002;
76 static const FlagsType AutoDelete = 0x0004;
77 static const FlagsType AutoSerialize = 0x0008;
78 static const FlagsType IsExitEvent = 0x0010;
79 static const FlagsType IsMainQueue = 0x0020;
81 static const FlagsType Initialized = 0xf000;
85 // The event queue is now a linked list of linked lists. The
86 // 'nextBin' pointer is to find the bin, where a bin is defined as
87 // when+priority. All events in the same bin will be stored in a
88 // second linked list (a stack) maintained by the 'nextInBin'
89 // pointer. The list will be accessed in LIFO order. The end
90 // result is that the insert/removal in 'nextBin' is
91 // linear/constant, and the lookup/removal in 'nextInBin' is
92 // constant/constant. Hopefully this is a significant improvement
93 // over the current fully linear insertion.
97 static Event *insertBefore(Event *event, Event *curr);
98 static Event *removeItem(Event *event, Event *last);
100 Tick _when; //!< timestamp when event should be processed
101 short _priority; //!< event priority
105 /// Global counter to generate unique IDs for Event instances
106 static Counter instanceCounter;
108 /// This event's unique ID. We can also use pointer values for
109 /// this but they're not consistent across runs making debugging
110 /// more difficult. Thus we use a global counter value when
114 /// queue to which this event belongs (though it may or may not be
115 /// scheduled on this queue yet)
120 Tick whenCreated; //!< time created
121 Tick whenScheduled; //!< time scheduled
125 setWhen(Tick when, EventQueue *q)
132 whenScheduled = curTick;
137 /// Accessor for flags.
141 return flags & PublicRead;
145 getFlags(Flags _flags) const
147 assert(flags.noneSet(~PublicRead));
148 return flags.isSet(_flags);
152 allFlags(Flags _flags) const
154 assert(_flags.noneSet(~PublicRead));
155 return flags.allSet(_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 Minimum_Pri = SHRT_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 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 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 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 Delayed_Writeback_Pri = -1,
212 /// Default is zero for historical reasons.
215 /// Serailization needs to occur before tick events also, so
216 /// that a serialize/unserialize is identical to an on-line
220 /// CPU ticks must come after other associated CPU events
221 /// (such as writebacks).
224 /// Statistics events (dump, reset, etc.) come after
225 /// everything else, but before exit.
228 /// Progress events come at the end.
229 Progress_Event_Pri = 95,
231 /// If we want to exit on this cycle, it's the very last thing
236 Maximum_Pri = SHRT_MAX
241 * @param queue that the event gets scheduled on
243 Event(Priority p = Default_Pri)
244 : nextBin(NULL), nextInBin(NULL), _priority(p)
247 instance = ++instanceCounter;
251 flags.set(Initialized);
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 int 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);
316 * Queue of events sorted in time order
318 class EventQueue : public Serializable
324 void insert(Event *event);
325 void remove(Event *event);
328 EventQueue(const std::string &n)
329 : objName(n), head(NULL)
332 virtual const std::string name() const { return objName; }
334 // schedule the given event on this queue
335 void schedule(Event *event, Tick when);
336 void deschedule(Event *event);
337 void reschedule(Event *event, Tick when, bool always = false);
339 Tick nextTick() const { return head->when(); }
342 // process all events up to the given timestamp. we inline a
343 // quick test to see if there are any events to process; if so,
344 // call the internal out-of-line version to process them all.
346 serviceEvents(Tick when)
349 if (nextTick() > when)
353 * @todo this assert is a good bug catcher. I need to
354 * make it true again.
356 //assert(head->when() >= when && "event scheduled in the past");
361 // default: process all events up to 'now' (curTick)
362 void serviceEvents() { serviceEvents(curTick); }
364 // return true if no events are queued
365 bool empty() const { return head == NULL; }
369 Tick nextEventTime() { return empty() ? curTick : head->when(); }
371 bool debugVerify() const;
374 virtual void serialize(std::ostream &os);
375 virtual void unserialize(Checkpoint *cp, const std::string §ion);
383 /** A pointer to this object's event queue */
387 EventManager(EventManager &em) : eventq(em.queue()) {}
388 EventManager(EventManager *em) : eventq(em ? em->queue() : NULL) {}
389 EventManager(EventQueue *eq) : eventq(eq) {}
398 schedule(Event &event, Tick when)
400 eventq->schedule(&event, when);
404 deschedule(Event &event)
406 eventq->deschedule(&event);
410 reschedule(Event &event, Tick when, bool always = false)
412 eventq->reschedule(&event, when, always);
416 schedule(Event *event, Tick when)
418 eventq->schedule(event, when);
422 deschedule(Event *event)
424 eventq->deschedule(event);
428 reschedule(Event *event, Tick when, bool always = false)
430 eventq->reschedule(event, when, always);
434 template <class T, void (T::* F)()>
436 DelayFunction(EventQueue *eventq, Tick when, T *object)
438 class DelayEvent : public Event
446 { this->setFlags(AutoDelete); }
447 void process() { (object->*F)(); }
448 const char *description() const { return "delay"; }
451 eventq->schedule(new DelayEvent(object), when);
454 template <class T, void (T::* F)()>
455 class EventWrapper : public Event
461 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
462 : Event(p), object(obj)
465 setFlags(AutoDelete);
468 void process() { (object->*F)(); }
472 EventQueue::schedule(Event *event, Tick when)
474 assert(when >= curTick);
475 assert(!event->scheduled());
477 assert((event->flags & Event::Initialized) == Event::Initialized);
480 event->setWhen(when, this);
482 event->flags.set(Event::Scheduled);
483 if (this == &mainEventQueue)
484 event->flags.set(Event::IsMainQueue);
486 event->flags.clear(Event::IsMainQueue);
489 event->trace("scheduled");
493 EventQueue::deschedule(Event *event)
495 assert(event->scheduled());
497 assert((event->flags & Event::Initialized) == Event::Initialized);
502 event->flags.clear(Event::Squashed);
503 event->flags.clear(Event::Scheduled);
505 if (event->flags.isSet(Event::AutoDelete))
509 event->trace("descheduled");
513 EventQueue::reschedule(Event *event, Tick when, bool always)
515 assert(when >= curTick);
516 assert(always || event->scheduled());
518 assert((event->flags & Event::Initialized) == Event::Initialized);
521 if (event->scheduled())
524 event->setWhen(when, this);
526 event->flags.clear(Event::Squashed);
527 event->flags.set(Event::Scheduled);
528 if (this == &mainEventQueue)
529 event->flags.set(Event::IsMainQueue);
531 event->flags.clear(Event::IsMainQueue);
534 event->trace("rescheduled");
538 operator<(const Event &l, const Event &r)
540 return l.when() < r.when() ||
541 (l.when() == r.when() && l.priority() < r.priority());
545 operator>(const Event &l, const Event &r)
547 return l.when() > r.when() ||
548 (l.when() == r.when() && l.priority() > r.priority());
552 operator<=(const Event &l, const Event &r)
554 return l.when() < r.when() ||
555 (l.when() == r.when() && l.priority() <= r.priority());
558 operator>=(const Event &l, const Event &r)
560 return l.when() > r.when() ||
561 (l.when() == r.when() && l.priority() >= r.priority());
565 operator==(const Event &l, const Event &r)
567 return l.when() == r.when() && l.priority() == r.priority();
571 operator!=(const Event &l, const Event &r)
573 return l.when() != r.when() || l.priority() != r.priority();
577 #endif // __SIM_EVENTQ_HH__