2 * Copyright (c) 2000-2005 The Regents of The University of Michigan
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.
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.
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/misc.hh"
48 #include "base/trace.hh"
49 #include "sim/serialize.hh"
50 #include "sim/host.hh"
52 class EventQueue; // forward declaration
54 //////////////////////
58 // Events on this queue are processed at the *beginning* of each
59 // cycle, before the pipeline simulation is performed.
61 // defined in eventq.cc
63 //////////////////////
64 extern EventQueue mainEventQueue;
67 * An item on an event queue. The action caused by a given
68 * event is specified by deriving a subclass and overriding the
69 * process() member function.
71 * Caution, the order of members is chosen to maximize data packing.
73 class Event : public Serializable, public FastAlloc
75 friend class EventQueue;
78 // The event queue is now a linked list of linked lists. The
79 // 'nextBin' pointer is to find the bin, where a bin is defined as
80 // when+priority. All events in the same bin will be stored in a
81 // second linked list (a stack) maintained by the 'nextInBin'
82 // pointer. The list will be accessed in LIFO order. The end
83 // result is that the insert/removal in 'nextBin' is
84 // linear/constant, and the lookup/removal in 'nextInBin' is
85 // constant/constant. Hopefully this is a significant improvement
86 // over the current fully linear insertion.
90 static Event *insertBefore(Event *event, Event *curr);
91 static Event *removeItem(Event *event, Event *last);
93 /// queue to which this event belongs (though it may or may not be
94 /// scheduled on this queue yet)
97 Tick _when; //!< timestamp when event should be processed
98 short _priority; //!< event priority
102 /// Global counter to generate unique IDs for Event instances
103 static Counter instanceCounter;
105 /// This event's unique ID. We can also use pointer values for
106 /// this but they're not consistent across runs making debugging
107 /// more difficult. Thus we use a global counter value when
113 Tick whenCreated; //!< time created
114 Tick whenScheduled; //!< time scheduled
123 whenScheduled = curTick;
137 bool getFlags(Flags f) const { return (_flags & f) == f; }
138 void setFlags(Flags f) { _flags |= f; }
139 void clearFlags(Flags f) { _flags &= ~f; }
142 EventQueue *queue() const { return _queue; }
144 // This function isn't really useful if TRACING_ON is not defined
145 virtual void trace(const char *action); //!< trace event activity
148 /// Event priorities, to provide tie-breakers for events scheduled
149 /// at the same cycle. Most events are scheduled at the default
150 /// priority; these values are used to control events that need to
151 /// be ordered within a cycle.
154 Minimum_Pri = SHRT_MIN,
156 /// If we enable tracing on a particular cycle, do that as the
157 /// very first thing so we don't miss any of the events on
158 /// that cycle (even if we enter the debugger).
159 Trace_Enable_Pri = -101,
161 /// Breakpoints should happen before anything else (except
162 /// enabling trace output), so we don't miss any action when
164 Debug_Break_Pri = -100,
166 /// CPU switches schedule the new CPU's tick event for the
167 /// same cycle (after unscheduling the old CPU's tick event).
168 /// The switch needs to come before any tick events to make
169 /// sure we don't tick both CPUs in the same cycle.
170 CPU_Switch_Pri = -31,
172 /// For some reason "delayed" inter-cluster writebacks are
173 /// scheduled before regular writebacks (which have default
174 /// priority). Steve?
175 Delayed_Writeback_Pri = -1,
177 /// Default is zero for historical reasons.
180 /// Serailization needs to occur before tick events also, so
181 /// that a serialize/unserialize is identical to an on-line
185 /// CPU ticks must come after other associated CPU events
186 /// (such as writebacks).
189 /// Statistics events (dump, reset, etc.) come after
190 /// everything else, but before exit.
193 /// Progress events come at the end.
194 Progress_Event_Pri = 95,
196 /// If we want to exit on this cycle, it's the very last thing
201 Maximum_Pri = SHRT_MAX
206 * @param queue that the event gets scheduled on
208 Event(EventQueue *q, Priority p = Default_Pri)
209 : nextBin(NULL), nextInBin(NULL), _queue(q), _priority(p), _flags(None)
212 instance = ++instanceCounter;
215 whenCreated = curTick;
225 virtual const std::string
229 return csprintf("Event_%d", instance);
231 return csprintf("Event_%x", (uintptr_t)this);
235 /// Return a C string describing the event. This string should
236 /// *not* be dynamically allocated; just a const char array
237 /// describing the event class.
238 virtual const char *description() const;
240 /// Dump the current event data
245 * This member function is invoked when the event is processed
246 * (occurs). There is no default implementation; each subclass
247 * must provide its own implementation. The event is not
248 * automatically deleted after it is processed (to allow for
249 * statically allocated event objects).
251 * If the AutoDestroy flag is set, the object is deleted once it
254 virtual void process() = 0;
256 /// Determine if the current event is scheduled
257 bool scheduled() const { return getFlags(Scheduled); }
259 /// Schedule the event with the current priority or default priority
260 void schedule(Tick t);
262 /// Reschedule the event with the current priority
263 // always parameter means to schedule if not already scheduled
264 void reschedule(Tick t, bool always = false);
266 /// Remove the event from the current schedule
269 /// Squash the current event
270 void squash() { setFlags(Squashed); }
272 /// Check whether the event is squashed
273 bool squashed() const { return getFlags(Squashed); }
275 /// See if this is a SimExitEvent (without resorting to RTTI)
276 bool isExitEvent() const { return getFlags(IsExitEvent); }
278 /// Get the time that the event is scheduled
279 Tick when() const { return _when; }
281 /// Get the event priority
282 int priority() const { return _priority; }
284 struct priority_compare
285 : public std::binary_function<Event *, Event *, bool>
288 operator()(const Event *l, const Event *r) const
290 return l->when() >= r->when() || l->priority() >= r->priority();
294 virtual void serialize(std::ostream &os);
295 virtual void unserialize(Checkpoint *cp, const std::string §ion);
298 template <class T, void (T::* F)()>
300 DelayFunction(Tick when, T *object)
302 class DelayEvent : public Event
308 DelayEvent(Tick when, T *o)
309 : Event(&mainEventQueue), object(o)
310 { setFlags(this->AutoDestroy); schedule(when); }
311 void process() { (object->*F)(); }
312 const char *description() const { return "delay"; }
315 new DelayEvent(when, object);
318 template <class T, void (T::* F)()>
319 class EventWrapper : public Event
325 EventWrapper(T *obj, bool del = false,
326 EventQueue *q = &mainEventQueue,
327 Priority p = Default_Pri)
328 : Event(q, p), object(obj)
331 setFlags(AutoDelete);
334 EventWrapper(T *obj, Tick t, bool del = false,
335 EventQueue *q = &mainEventQueue,
336 Priority p = Default_Pri)
337 : Event(q, p), object(obj)
340 setFlags(AutoDelete);
344 void process() { (object->*F)(); }
348 * Queue of events sorted in time order
350 class EventQueue : public Serializable
358 void insert(Event *event);
359 void remove(Event *event);
364 EventQueue(const std::string &n)
365 : objName(n), head(NULL)
368 virtual const std::string name() const { return objName; }
370 // schedule the given event on this queue
371 void schedule(Event *ev, Tick when);
372 void deschedule(Event *ev);
373 void reschedule(Event *ev, Tick when);
375 Tick nextTick() const { return head->when(); }
378 // process all events up to the given timestamp. we inline a
379 // quick test to see if there are any events to process; if so,
380 // call the internal out-of-line version to process them all.
382 serviceEvents(Tick when)
385 if (nextTick() > when)
389 * @todo this assert is a good bug catcher. I need to
390 * make it true again.
392 //assert(head->when() >= when && "event scheduled in the past");
397 // default: process all events up to 'now' (curTick)
398 void serviceEvents() { serviceEvents(curTick); }
400 // return true if no events are queued
401 bool empty() const { return head == NULL; }
405 Tick nextEventTime() { return empty() ? curTick : head->when(); }
407 bool debugVerify() const;
409 virtual void serialize(std::ostream &os);
410 virtual void unserialize(Checkpoint *cp, const std::string §ion);
414 //////////////////////
418 // can't put these inside declaration due to circular dependence
419 // between Event and EventQueue classes.
421 //////////////////////
423 // schedule at specified time (place on event queue specified via
426 Event::schedule(Tick when)
428 _queue->schedule(this, when);
434 _queue->deschedule(this);
438 Event::reschedule(Tick when, bool always)
441 _queue->reschedule(this, when);
444 _queue->schedule(this, when);
449 operator<(const Event &l, const Event &r)
451 return l.when() < r.when() ||
452 (l.when() == r.when() && l.priority() < r.priority());
456 operator>(const Event &l, const Event &r)
458 return l.when() > r.when() ||
459 (l.when() == r.when() && l.priority() > r.priority());
463 operator<=(const Event &l, const Event &r)
465 return l.when() < r.when() ||
466 (l.when() == r.when() && l.priority() <= r.priority());
469 operator>=(const Event &l, const Event &r)
471 return l.when() > r.when() ||
472 (l.when() == r.when() && l.priority() >= r.priority());
476 operator==(const Event &l, const Event &r)
478 return l.when() == r.when() && l.priority() == r.priority();
482 operator!=(const Event &l, const Event &r)
484 return l.when() != r.when() || l.priority() != r.priority();
488 EventQueue::schedule(Event *event, Tick when)
490 assert(when >= curTick);
491 assert(!event->scheduled());
493 event->setWhen(when);
495 event->setFlags(Event::Scheduled);
498 event->trace("scheduled");
502 EventQueue::deschedule(Event *event)
504 assert(event->scheduled());
508 event->clearFlags(Event::Squashed);
509 event->clearFlags(Event::Scheduled);
511 if (event->getFlags(Event::AutoDelete))
515 event->trace("descheduled");
519 EventQueue::reschedule(Event *event, Tick when)
521 assert(when >= curTick);
522 assert(event->scheduled());
525 event->setWhen(when);
527 event->clearFlags(Event::Squashed);
530 event->trace("rescheduled");
533 #endif // __SIM_EVENTQ_HH__