1/*
2 * Copyright (c) 2000-2005 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 * Authors: Steve Reinhardt
29 * Nathan Binkert
30 */
31
32/* @file
33 * EventQueue interfaces
34 */
35
36#ifndef __SIM_EVENTQ_HH__
37#define __SIM_EVENTQ_HH__
38
39#include <algorithm>
40#include <cassert>
41#include <climits>
42#include <iosfwd>
43#include <string>
44
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 "sim/serialize.hh"
51
52class EventQueue; // forward declaration
53
54extern EventQueue mainEventQueue;
55
56/*
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.
60 *
61 * Caution, the order of members is chosen to maximize data packing.
62 */
63class Event : public Serializable, public FastAlloc
64{
65 friend class EventQueue;
66
67 protected:
68 typedef short FlagsType;
69 typedef ::Flags<FlagsType> Flags;
70
71 static const FlagsType PublicRead = 0x003f;
72 static const FlagsType PublicWrite = 0x001d;
73 static const FlagsType Squashed = 0x0001;
74 static const FlagsType Scheduled = 0x0002;
75 static const FlagsType AutoDelete = 0x0004;
76 static const FlagsType AutoSerialize = 0x0008;
77 static const FlagsType IsExitEvent = 0x0010;
78 static const FlagsType IsMainQueue = 0x0020;
79#ifdef EVENTQ_DEBUG
80 static const FlagsType Initialized = 0xf000;
81#endif
82
83 public:
84 typedef int8_t Priority;
85
86 private:
87 // The event queue is now a linked list of linked lists. The
88 // 'nextBin' pointer is to find the bin, where a bin is defined as
89 // when+priority. All events in the same bin will be stored in a
90 // second linked list (a stack) maintained by the 'nextInBin'
91 // pointer. The list will be accessed in LIFO order. The end
92 // result is that the insert/removal in 'nextBin' is
93 // linear/constant, and the lookup/removal in 'nextInBin' is
94 // constant/constant. Hopefully this is a significant improvement
95 // over the current fully linear insertion.
96 Event *nextBin;
97 Event *nextInBin;
98
99 static Event *insertBefore(Event *event, Event *curr);
100 static Event *removeItem(Event *event, Event *last);
101
102 Tick _when; //!< timestamp when event should be processed
100 short _priority; //!< event priority
103 Priority _priority; //!< event priority
104 Flags flags;
105
106#ifndef NDEBUG
107 /// Global counter to generate unique IDs for Event instances
108 static Counter instanceCounter;
109
110 /// This event's unique ID. We can also use pointer values for
111 /// this but they're not consistent across runs making debugging
112 /// more difficult. Thus we use a global counter value when
113 /// debugging.
114 Counter instance;
115
116 /// queue to which this event belongs (though it may or may not be
117 /// scheduled on this queue yet)
118 EventQueue *queue;
119#endif
120
121#ifdef EVENTQ_DEBUG
122 Tick whenCreated; //!< time created
123 Tick whenScheduled; //!< time scheduled
124#endif
125
126 void
127 setWhen(Tick when, EventQueue *q)
128 {
129 _when = when;
130#ifndef NDEBUG
131 queue = q;
132#endif
133#ifdef EVENTQ_DEBUG
134 whenScheduled = curTick;
135#endif
136 }
137
138 protected:
139 /// Accessor for flags.
140 Flags
141 getFlags() const
142 {
143 return flags & PublicRead;
144 }
145
146 Flags
147 getFlags(Flags _flags) const
148 {
149 assert(flags.noneSet(~PublicRead));
150 return flags.isSet(_flags);
151 }
152
153 Flags
154 allFlags(Flags _flags) const
155 {
156 assert(_flags.noneSet(~PublicRead));
157 return flags.allSet(_flags);
158 }
159
160 /// Accessor for flags.
161 void
162 setFlags(Flags _flags)
163 {
164 assert(_flags.noneSet(~PublicWrite));
165 flags.set(_flags);
166 }
167
168 void
169 clearFlags(Flags _flags)
170 {
171 assert(_flags.noneSet(~PublicWrite));
172 flags.clear(_flags);
173 }
174
175 void
176 clearFlags()
177 {
178 flags.clear(PublicWrite);
179 }
180
181 // This function isn't really useful if TRACING_ON is not defined
182 virtual void trace(const char *action); //!< trace event activity
183
184 public:
185 /// Event priorities, to provide tie-breakers for events scheduled
186 /// at the same cycle. Most events are scheduled at the default
187 /// priority; these values are used to control events that need to
188 /// be ordered within a cycle.
186 enum Priority {
187 /// Minimum priority
188 Minimum_Pri = SHRT_MIN,
189
190 /// If we enable tracing on a particular cycle, do that as the
191 /// very first thing so we don't miss any of the events on
192 /// that cycle (even if we enter the debugger).
193 Trace_Enable_Pri = -101,
190 /// Minimum priority
191 static const Priority Minimum_Pri = SCHAR_MIN;
192
195 /// Breakpoints should happen before anything else (except
196 /// enabling trace output), so we don't miss any action when
197 /// debugging.
198 Debug_Break_Pri = -100,
193 /// If we enable tracing on a particular cycle, do that as the
194 /// very first thing so we don't miss any of the events on
195 /// that cycle (even if we enter the debugger).
196 static const Priority Trace_Enable_Pri = -101;
197
200 /// CPU switches schedule the new CPU's tick event for the
201 /// same cycle (after unscheduling the old CPU's tick event).
202 /// The switch needs to come before any tick events to make
203 /// sure we don't tick both CPUs in the same cycle.
204 CPU_Switch_Pri = -31,
198 /// Breakpoints should happen before anything else (except
199 /// enabling trace output), so we don't miss any action when
200 /// debugging.
201 static const Priority Debug_Break_Pri = -100;
202
206 /// For some reason "delayed" inter-cluster writebacks are
207 /// scheduled before regular writebacks (which have default
208 /// priority). Steve?
209 Delayed_Writeback_Pri = -1,
203 /// CPU switches schedule the new CPU's tick event for the
204 /// same cycle (after unscheduling the old CPU's tick event).
205 /// The switch needs to come before any tick events to make
206 /// sure we don't tick both CPUs in the same cycle.
207 static const Priority CPU_Switch_Pri = -31;
208
211 /// Default is zero for historical reasons.
212 Default_Pri = 0,
209 /// For some reason "delayed" inter-cluster writebacks are
210 /// scheduled before regular writebacks (which have default
211 /// priority). Steve?
212 static const Priority Delayed_Writeback_Pri = -1;
213
214 /// Serailization needs to occur before tick events also, so
215 /// that a serialize/unserialize is identical to an on-line
216 /// CPU switch.
217 Serialize_Pri = 32,
214 /// Default is zero for historical reasons.
215 static const Priority Default_Pri = 0;
216
219 /// CPU ticks must come after other associated CPU events
220 /// (such as writebacks).
221 CPU_Tick_Pri = 50,
217 /// Serailization needs to occur before tick events also, so
218 /// that a serialize/unserialize is identical to an on-line
219 /// CPU switch.
220 static const Priority Serialize_Pri = 32;
221
223 /// Statistics events (dump, reset, etc.) come after
224 /// everything else, but before exit.
225 Stat_Event_Pri = 90,
222 /// CPU ticks must come after other associated CPU events
223 /// (such as writebacks).
224 static const Priority CPU_Tick_Pri = 50;
225
227 /// Progress events come at the end.
228 Progress_Event_Pri = 95,
226 /// Statistics events (dump, reset, etc.) come after
227 /// everything else, but before exit.
228 static const Priority Stat_Event_Pri = 90;
229
230 /// If we want to exit on this cycle, it's the very last thing
231 /// we do.
232 Sim_Exit_Pri = 100,
230 /// Progress events come at the end.
231 static const Priority Progress_Event_Pri = 95;
232
234 /// Maximum priority
235 Maximum_Pri = SHRT_MAX
236 };
233 /// If we want to exit on this cycle, it's the very last thing
234 /// we do.
235 static const Priority Sim_Exit_Pri = 100;
236
237 /// Maximum priority
238 static const Priority Maximum_Pri = SCHAR_MAX;
239
240 /*
241 * Event constructor
242 * @param queue that the event gets scheduled on
243 */
244 Event(Priority p = Default_Pri)
245 : nextBin(NULL), nextInBin(NULL), _priority(p)
246 {
247#ifndef NDEBUG
248 instance = ++instanceCounter;
249 queue = NULL;
250#endif
251#ifdef EVENTQ_DEBUG
252 flags.set(Initialized);
253 whenCreated = curTick;
254 whenScheduled = 0;
255#endif
256 }
257
258 virtual ~Event();
259 virtual const std::string name() const;
260
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;
265
266 /// Dump the current event data
267 void dump() const;
268
269 public:
270 /*
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).
276 *
277 * If the AutoDestroy flag is set, the object is deleted once it
278 * is processed.
279 */
280 virtual void process() = 0;
281
282 /// Determine if the current event is scheduled
283 bool scheduled() const { return flags.isSet(Scheduled); }
284
285 /// Squash the current event
286 void squash() { flags.set(Squashed); }
287
288 /// Check whether the event is squashed
289 bool squashed() const { return flags.isSet(Squashed); }
290
291 /// See if this is a SimExitEvent (without resorting to RTTI)
292 bool isExitEvent() const { return flags.isSet(IsExitEvent); }
293
294 /// Get the time that the event is scheduled
295 Tick when() const { return _when; }
296
297 /// Get the event priority
296 int priority() const { return _priority; }
298 Priority priority() const { return _priority; }
299
300#ifndef SWIG
301 struct priority_compare
302 : public std::binary_function<Event *, Event *, bool>
303 {
304 bool
305 operator()(const Event *l, const Event *r) const
306 {
307 return l->when() >= r->when() || l->priority() >= r->priority();
308 }
309 };
310
311 virtual void serialize(std::ostream &os);
312 virtual void unserialize(Checkpoint *cp, const std::string &section);
313#endif
314};
315
316#ifndef SWIG
317inline bool
318operator<(const Event &l, const Event &r)
319{
320 return l.when() < r.when() ||
321 (l.when() == r.when() && l.priority() < r.priority());
322}
323
324inline bool
325operator>(const Event &l, const Event &r)
326{
327 return l.when() > r.when() ||
328 (l.when() == r.when() && l.priority() > r.priority());
329}
330
331inline bool
332operator<=(const Event &l, const Event &r)
333{
334 return l.when() < r.when() ||
335 (l.when() == r.when() && l.priority() <= r.priority());
336}
337inline bool
338operator>=(const Event &l, const Event &r)
339{
340 return l.when() > r.when() ||
341 (l.when() == r.when() && l.priority() >= r.priority());
342}
343
344inline bool
345operator==(const Event &l, const Event &r)
346{
347 return l.when() == r.when() && l.priority() == r.priority();
348}
349
350inline bool
351operator!=(const Event &l, const Event &r)
352{
353 return l.when() != r.when() || l.priority() != r.priority();
354}
355#endif
356
357/*
358 * Queue of events sorted in time order
359 */
360class EventQueue : public Serializable
361{
362 private:
363 std::string objName;
364 Event *head;
365
366 void insert(Event *event);
367 void remove(Event *event);
368
369 public:
370 EventQueue(const std::string &n)
371 : objName(n), head(NULL)
372 {}
373
374 virtual const std::string name() const { return objName; }
375
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);
380
381 Tick nextTick() const { return head->when(); }
382 Event *serviceOne();
383
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.
387 void
388 serviceEvents(Tick when)
389 {
390 while (!empty()) {
391 if (nextTick() > when)
392 break;
393
394 /**
395 * @todo this assert is a good bug catcher. I need to
396 * make it true again.
397 */
398 //assert(head->when() >= when && "event scheduled in the past");
399 serviceOne();
400 }
401 }
402
403 // default: process all events up to 'now' (curTick)
404 void serviceEvents() { serviceEvents(curTick); }
405
406 // return true if no events are queued
407 bool empty() const { return head == NULL; }
408
409 void dump() const;
410
411 Tick nextEventTime() { return empty() ? curTick : head->when(); }
412
413 bool debugVerify() const;
414
415#ifndef SWIG
416 virtual void serialize(std::ostream &os);
417 virtual void unserialize(Checkpoint *cp, const std::string &section);
418#endif
419};
420
421#ifndef SWIG
422class EventManager
423{
424 protected:
425 /** A pointer to this object's event queue */
426 EventQueue *eventq;
427
428 public:
429 EventManager(EventManager &em) : eventq(em.queue()) {}
430 EventManager(EventManager *em) : eventq(em ? em->queue() : NULL) {}
431 EventManager(EventQueue *eq) : eventq(eq) {}
432
433 EventQueue *
434 queue() const
435 {
436 return eventq;
437 }
438
439 void
440 schedule(Event &event, Tick when)
441 {
442 eventq->schedule(&event, when);
443 }
444
445 void
446 deschedule(Event &event)
447 {
448 eventq->deschedule(&event);
449 }
450
451 void
452 reschedule(Event &event, Tick when, bool always = false)
453 {
454 eventq->reschedule(&event, when, always);
455 }
456
457 void
458 schedule(Event *event, Tick when)
459 {
460 eventq->schedule(event, when);
461 }
462
463 void
464 deschedule(Event *event)
465 {
466 eventq->deschedule(event);
467 }
468
469 void
470 reschedule(Event *event, Tick when, bool always = false)
471 {
472 eventq->reschedule(event, when, always);
473 }
474};
475
476inline void
477EventQueue::schedule(Event *event, Tick when)
478{
479 assert((UTick)when >= (UTick)curTick);
480 assert(!event->scheduled());
481#ifdef EVENTQ_DEBUG
482 assert((event->flags & Event::Initialized) == Event::Initialized);
483#endif
484
485 event->setWhen(when, this);
486 insert(event);
487 event->flags.set(Event::Scheduled);
488 if (this == &mainEventQueue)
489 event->flags.set(Event::IsMainQueue);
490 else
491 event->flags.clear(Event::IsMainQueue);
492
493 if (DTRACE(Event))
494 event->trace("scheduled");
495}
496
497inline void
498EventQueue::deschedule(Event *event)
499{
500 assert(event->scheduled());
501#ifdef EVENTQ_DEBUG
502 assert((event->flags & Event::Initialized) == Event::Initialized);
503#endif
504
505 remove(event);
506
507 event->flags.clear(Event::Squashed);
508 event->flags.clear(Event::Scheduled);
509
510 if (event->flags.isSet(Event::AutoDelete))
511 delete event;
512
513 if (DTRACE(Event))
514 event->trace("descheduled");
515}
516
517inline void
518EventQueue::reschedule(Event *event, Tick when, bool always)
519{
520 assert(when >= curTick);
521 assert(always || event->scheduled());
522#ifdef EVENTQ_DEBUG
523 assert((event->flags & Event::Initialized) == Event::Initialized);
524#endif
525
526 if (event->scheduled())
527 remove(event);
528
529 event->setWhen(when, this);
530 insert(event);
531 event->flags.clear(Event::Squashed);
532 event->flags.set(Event::Scheduled);
533 if (this == &mainEventQueue)
534 event->flags.set(Event::IsMainQueue);
535 else
536 event->flags.clear(Event::IsMainQueue);
537
538 if (DTRACE(Event))
539 event->trace("rescheduled");
540}
541
542template <class T, void (T::* F)()>
543void
544DelayFunction(EventQueue *eventq, Tick when, T *object)
545{
546 class DelayEvent : public Event
547 {
548 private:
549 T *object;
550
551 public:
552 DelayEvent(T *o)
553 : object(o)
554 { this->setFlags(AutoDelete); }
555 void process() { (object->*F)(); }
556 const char *description() const { return "delay"; }
557 };
558
559 eventq->schedule(new DelayEvent(object), when);
560}
561
562template <class T, void (T::* F)()>
563class EventWrapper : public Event
564{
565 private:
566 T *object;
567
568 public:
569 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
570 : Event(p), object(obj)
571 {
572 if (del)
573 setFlags(AutoDelete);
574 }
575
576 void process() { (object->*F)(); }
577
578 const std::string
579 name() const
580 {
581 return object->name() + ".wrapped_event";
582 }
583
584 const char *description() const { return "EventWrapped"; }
585};
586#endif
587
588#endif // __SIM_EVENTQ_HH__