2 * Copyright (c) 2000-2005 The Regents of The University of Michigan
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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
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26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 * Authors: Steve Reinhardt
33 * EventQueue interfaces
36 #ifndef __SIM_EVENTQ_HH__
37 #define __SIM_EVENTQ_HH__
45 #include "base/fast_alloc.hh"
46 #include "base/flags.hh"
47 #include "base/misc.hh"
48 #include "base/trace.hh"
49 #include "base/types.hh"
50 #include "debug/Event.hh"
51 #include "sim/serialize.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; // public readable flags
73 static const FlagsType PublicWrite = 0x001d; // public writable flags
74 static const FlagsType Squashed = 0x0001; // has been squashed
75 static const FlagsType Scheduled = 0x0002; // has been scheduled
76 static const FlagsType AutoDelete = 0x0004; // delete after dispatch
77 static const FlagsType AutoSerialize = 0x0008; // must be serialized
78 static const FlagsType IsExitEvent = 0x0010; // special exit event
79 static const FlagsType IsMainQueue = 0x0020; // on main event queue
80 static const FlagsType Initialized = 0x7a40; // somewhat random bits
81 static const FlagsType InitMask = 0xffc0; // mask for init bits
86 return this && (flags & InitMask) == Initialized;
90 typedef int8_t Priority;
93 // The event queue is now a linked list of linked lists. The
94 // 'nextBin' pointer is to find the bin, where a bin is defined as
95 // when+priority. All events in the same bin will be stored in a
96 // second linked list (a stack) maintained by the 'nextInBin'
97 // pointer. The list will be accessed in LIFO order. The end
98 // result is that the insert/removal in 'nextBin' is
99 // linear/constant, and the lookup/removal in 'nextInBin' is
100 // constant/constant. Hopefully this is a significant improvement
101 // over the current fully linear insertion.
105 static Event *insertBefore(Event *event, Event *curr);
106 static Event *removeItem(Event *event, Event *last);
108 Tick _when; //!< timestamp when event should be processed
109 Priority _priority; //!< event priority
113 /// Global counter to generate unique IDs for Event instances
114 static Counter instanceCounter;
116 /// This event's unique ID. We can also use pointer values for
117 /// this but they're not consistent across runs making debugging
118 /// more difficult. Thus we use a global counter value when
122 /// queue to which this event belongs (though it may or may not be
123 /// scheduled on this queue yet)
128 Tick whenCreated; //!< time created
129 Tick whenScheduled; //!< time scheduled
133 setWhen(Tick when, EventQueue *q)
140 whenScheduled = curTick();
145 /// Accessor for flags.
149 return flags & PublicRead;
153 isFlagSet(Flags _flags) const
155 assert(_flags.noneSet(~PublicRead));
156 return flags.isSet(_flags);
159 /// Accessor for flags.
161 setFlags(Flags _flags)
163 assert(_flags.noneSet(~PublicWrite));
168 clearFlags(Flags _flags)
170 assert(_flags.noneSet(~PublicWrite));
177 flags.clear(PublicWrite);
180 // This function isn't really useful if TRACING_ON is not defined
181 virtual void trace(const char *action); //!< trace event activity
184 /// Event priorities, to provide tie-breakers for events scheduled
185 /// at the same cycle. Most events are scheduled at the default
186 /// priority; these values are used to control events that need to
187 /// be ordered within a cycle.
190 static const Priority Minimum_Pri = SCHAR_MIN;
192 /// If we enable tracing on a particular cycle, do that as the
193 /// very first thing so we don't miss any of the events on
194 /// that cycle (even if we enter the debugger).
195 static const Priority Trace_Enable_Pri = -101;
197 /// Breakpoints should happen before anything else (except
198 /// enabling trace output), so we don't miss any action when
200 static const Priority Debug_Break_Pri = -100;
202 /// CPU switches schedule the new CPU's tick event for the
203 /// same cycle (after unscheduling the old CPU's tick event).
204 /// The switch needs to come before any tick events to make
205 /// sure we don't tick both CPUs in the same cycle.
206 static const Priority CPU_Switch_Pri = -31;
208 /// For some reason "delayed" inter-cluster writebacks are
209 /// scheduled before regular writebacks (which have default
210 /// priority). Steve?
211 static const Priority Delayed_Writeback_Pri = -1;
213 /// Default is zero for historical reasons.
214 static const Priority Default_Pri = 0;
216 /// Serailization needs to occur before tick events also, so
217 /// that a serialize/unserialize is identical to an on-line
219 static const Priority Serialize_Pri = 32;
221 /// CPU ticks must come after other associated CPU events
222 /// (such as writebacks).
223 static const Priority CPU_Tick_Pri = 50;
225 /// Statistics events (dump, reset, etc.) come after
226 /// everything else, but before exit.
227 static const Priority Stat_Event_Pri = 90;
229 /// Progress events come at the end.
230 static const Priority Progress_Event_Pri = 95;
232 /// If we want to exit on this cycle, it's the very last thing
234 static const Priority Sim_Exit_Pri = 100;
237 static const Priority Maximum_Pri = SCHAR_MAX;
241 * @param queue that the event gets scheduled on
243 Event(Priority p = Default_Pri, Flags f = 0)
244 : nextBin(NULL), nextInBin(NULL), _priority(p),
245 flags(Initialized | f)
247 assert(f.noneSet(~PublicWrite));
249 instance = ++instanceCounter;
253 whenCreated = curTick();
259 virtual const std::string name() const;
261 /// Return a C string describing the event. This string should
262 /// *not* be dynamically allocated; just a const char array
263 /// describing the event class.
264 virtual const char *description() const;
266 /// Dump the current event data
271 * This member function is invoked when the event is processed
272 * (occurs). There is no default implementation; each subclass
273 * must provide its own implementation. The event is not
274 * automatically deleted after it is processed (to allow for
275 * statically allocated event objects).
277 * If the AutoDestroy flag is set, the object is deleted once it
280 virtual void process() = 0;
282 /// Determine if the current event is scheduled
283 bool scheduled() const { return flags.isSet(Scheduled); }
285 /// Squash the current event
286 void squash() { flags.set(Squashed); }
288 /// Check whether the event is squashed
289 bool squashed() const { return flags.isSet(Squashed); }
291 /// See if this is a SimExitEvent (without resorting to RTTI)
292 bool isExitEvent() const { return flags.isSet(IsExitEvent); }
294 /// Get the time that the event is scheduled
295 Tick when() const { return _when; }
297 /// Get the event priority
298 Priority priority() const { return _priority; }
301 struct priority_compare
302 : public std::binary_function<Event *, Event *, bool>
305 operator()(const Event *l, const Event *r) const
307 return l->when() >= r->when() || l->priority() >= r->priority();
311 virtual void serialize(std::ostream &os);
312 virtual void unserialize(Checkpoint *cp, const std::string §ion);
318 operator<(const Event &l, const Event &r)
320 return l.when() < r.when() ||
321 (l.when() == r.when() && l.priority() < r.priority());
325 operator>(const Event &l, const Event &r)
327 return l.when() > r.when() ||
328 (l.when() == r.when() && l.priority() > r.priority());
332 operator<=(const Event &l, const Event &r)
334 return l.when() < r.when() ||
335 (l.when() == r.when() && l.priority() <= r.priority());
338 operator>=(const Event &l, const Event &r)
340 return l.when() > r.when() ||
341 (l.when() == r.when() && l.priority() >= r.priority());
345 operator==(const Event &l, const Event &r)
347 return l.when() == r.when() && l.priority() == r.priority();
351 operator!=(const Event &l, const Event &r)
353 return l.when() != r.when() || l.priority() != r.priority();
358 * Queue of events sorted in time order
360 class EventQueue : public Serializable
366 void insert(Event *event);
367 void remove(Event *event);
369 EventQueue(const EventQueue &);
370 const EventQueue &operator=(const EventQueue &);
373 EventQueue(const std::string &n);
375 virtual const std::string name() const { return objName; }
377 // schedule the given event on this queue
378 void schedule(Event *event, Tick when);
379 void deschedule(Event *event);
380 void reschedule(Event *event, Tick when, bool always = false);
382 Tick nextTick() const { return head->when(); }
385 // process all events up to the given timestamp. we inline a
386 // quick test to see if there are any events to process; if so,
387 // call the internal out-of-line version to process them all.
389 serviceEvents(Tick when)
392 if (nextTick() > when)
396 * @todo this assert is a good bug catcher. I need to
397 * make it true again.
399 //assert(head->when() >= when && "event scheduled in the past");
404 // return true if no events are queued
405 bool empty() const { return head == NULL; }
409 bool debugVerify() const;
412 * function for replacing the head of the event queue, so that a
413 * different set of events can run without disturbing events that have
414 * already been scheduled. Already scheduled events can be processed
415 * by replacing the original head back.
416 * USING THIS FUNCTION CAN BE DANGEROUS TO THE HEALTH OF THE SIMULATOR.
417 * NOT RECOMMENDED FOR USE.
419 Event* replaceHead(Event* s);
422 virtual void serialize(std::ostream &os);
423 virtual void unserialize(Checkpoint *cp, const std::string §ion);
431 /** A pointer to this object's event queue */
435 EventManager(EventManager &em) : eventq(em.queue()) {}
436 EventManager(EventManager *em) : eventq(em ? em->queue() : NULL) {}
437 EventManager(EventQueue *eq) : eventq(eq) {}
445 operator EventQueue *() const
451 schedule(Event &event, Tick when)
453 eventq->schedule(&event, when);
457 deschedule(Event &event)
459 eventq->deschedule(&event);
463 reschedule(Event &event, Tick when, bool always = false)
465 eventq->reschedule(&event, when, always);
469 schedule(Event *event, Tick when)
471 eventq->schedule(event, when);
475 deschedule(Event *event)
477 eventq->deschedule(event);
481 reschedule(Event *event, Tick when, bool always = false)
483 eventq->reschedule(event, when, always);
488 EventQueue::schedule(Event *event, Tick when)
490 // Typecasting Tick->Utick here since gcc
491 // complains about signed overflow
492 assert((UTick)when >= (UTick)curTick());
493 assert(!event->scheduled());
494 assert(event->initialized());
496 event->setWhen(when, this);
498 event->flags.set(Event::Scheduled);
499 if (this == &mainEventQueue)
500 event->flags.set(Event::IsMainQueue);
502 event->flags.clear(Event::IsMainQueue);
505 event->trace("scheduled");
509 EventQueue::deschedule(Event *event)
511 assert(event->scheduled());
512 assert(event->initialized());
516 event->flags.clear(Event::Squashed);
517 event->flags.clear(Event::Scheduled);
519 if (event->flags.isSet(Event::AutoDelete))
523 event->trace("descheduled");
527 EventQueue::reschedule(Event *event, Tick when, bool always)
529 // Typecasting Tick->Utick here since gcc
530 // complains about signed overflow
531 assert((UTick)when >= (UTick)curTick());
532 assert(always || event->scheduled());
533 assert(event->initialized());
535 if (event->scheduled())
538 event->setWhen(when, this);
540 event->flags.clear(Event::Squashed);
541 event->flags.set(Event::Scheduled);
542 if (this == &mainEventQueue)
543 event->flags.set(Event::IsMainQueue);
545 event->flags.clear(Event::IsMainQueue);
548 event->trace("rescheduled");
551 template <class T, void (T::* F)()>
553 DelayFunction(EventQueue *eventq, Tick when, T *object)
555 class DelayEvent : public Event
562 : Event(Default_Pri, AutoDelete), object(o)
564 void process() { (object->*F)(); }
565 const char *description() const { return "delay"; }
568 eventq->schedule(new DelayEvent(object), when);
571 template <class T, void (T::* F)()>
572 class EventWrapper : public Event
578 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
579 : Event(p), object(obj)
582 setFlags(AutoDelete);
585 EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
586 : Event(p), object(&obj)
589 setFlags(AutoDelete);
592 void process() { (object->*F)(); }
597 return object->name() + ".wrapped_event";
600 const char *description() const { return "EventWrapped"; }
604 #endif // __SIM_EVENTQ_HH__