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 "debug/Event.hh"
51#include "sim/serialize.hh"
52
53class EventQueue; // forward declaration
54
55extern EventQueue mainEventQueue;
56
57/*
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.
61 *
62 * Caution, the order of members is chosen to maximize data packing.
63 */
64class Event : public Serializable, public FastAlloc
65{
66 friend class EventQueue;
67
68 protected:
69 typedef short FlagsType;
70 typedef ::Flags<FlagsType> Flags;
71
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
82
83 bool
84 initialized() const
85 {
86 return this && (flags & InitMask) == Initialized;
87 }
88
89 public:
90 typedef int8_t Priority;
91
92 private:
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.
102 Event *nextBin;
103 Event *nextInBin;
104
105 static Event *insertBefore(Event *event, Event *curr);
106 static Event *removeItem(Event *event, Event *last);
107
108 Tick _when; //!< timestamp when event should be processed
109 Priority _priority; //!< event priority
110 Flags flags;
111
112#ifndef NDEBUG
113 /// Global counter to generate unique IDs for Event instances
114 static Counter instanceCounter;
115
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
119 /// debugging.
120 Counter instance;
121
122 /// queue to which this event belongs (though it may or may not be
123 /// scheduled on this queue yet)
124 EventQueue *queue;
125#endif
126
127#ifdef EVENTQ_DEBUG
128 Tick whenCreated; //!< time created
129 Tick whenScheduled; //!< time scheduled
130#endif
131
132 void
133 setWhen(Tick when, EventQueue *q)
134 {
135 _when = when;
136#ifndef NDEBUG
137 queue = q;
138#endif
139#ifdef EVENTQ_DEBUG
140 whenScheduled = curTick();
141#endif
142 }
143
144 protected:
145 /// Accessor for flags.
146 Flags
147 getFlags() const
148 {
149 return flags & PublicRead;
150 }
151
152 Flags
153 getFlags(Flags _flags) const
154 {
155 assert(_flags.noneSet(~PublicRead));
156 return flags.isSet(_flags);
157 }
158
159 Flags
160 allFlags(Flags _flags) const
161 {
162 assert(_flags.noneSet(~PublicRead));
163 return flags.allSet(_flags);
164 }
165
166 /// Accessor for flags.
167 void
168 setFlags(Flags _flags)
169 {
170 assert(_flags.noneSet(~PublicWrite));
171 flags.set(_flags);
172 }
173
174 void
175 clearFlags(Flags _flags)
176 {
177 assert(_flags.noneSet(~PublicWrite));
178 flags.clear(_flags);
179 }
180
181 void
182 clearFlags()
183 {
184 flags.clear(PublicWrite);
185 }
186
187 // This function isn't really useful if TRACING_ON is not defined
188 virtual void trace(const char *action); //!< trace event activity
189
190 public:
191 /// Event priorities, to provide tie-breakers for events scheduled
192 /// at the same cycle. Most events are scheduled at the default
193 /// priority; these values are used to control events that need to
194 /// be ordered within a cycle.
195
196 /// Minimum priority
197 static const Priority Minimum_Pri = SCHAR_MIN;
198
199 /// If we enable tracing on a particular cycle, do that as the
200 /// very first thing so we don't miss any of the events on
201 /// that cycle (even if we enter the debugger).
202 static const Priority Trace_Enable_Pri = -101;
203
204 /// Breakpoints should happen before anything else (except
205 /// enabling trace output), so we don't miss any action when
206 /// debugging.
207 static const Priority Debug_Break_Pri = -100;
208
209 /// CPU switches schedule the new CPU's tick event for the
210 /// same cycle (after unscheduling the old CPU's tick event).
211 /// The switch needs to come before any tick events to make
212 /// sure we don't tick both CPUs in the same cycle.
213 static const Priority CPU_Switch_Pri = -31;
214
215 /// For some reason "delayed" inter-cluster writebacks are
216 /// scheduled before regular writebacks (which have default
217 /// priority). Steve?
218 static const Priority Delayed_Writeback_Pri = -1;
219
220 /// Default is zero for historical reasons.
221 static const Priority Default_Pri = 0;
222
223 /// Serailization needs to occur before tick events also, so
224 /// that a serialize/unserialize is identical to an on-line
225 /// CPU switch.
226 static const Priority Serialize_Pri = 32;
227
228 /// CPU ticks must come after other associated CPU events
229 /// (such as writebacks).
230 static const Priority CPU_Tick_Pri = 50;
231
232 /// Statistics events (dump, reset, etc.) come after
233 /// everything else, but before exit.
234 static const Priority Stat_Event_Pri = 90;
235
236 /// Progress events come at the end.
237 static const Priority Progress_Event_Pri = 95;
238
239 /// If we want to exit on this cycle, it's the very last thing
240 /// we do.
241 static const Priority Sim_Exit_Pri = 100;
242
243 /// Maximum priority
244 static const Priority Maximum_Pri = SCHAR_MAX;
245
246 /*
247 * Event constructor
248 * @param queue that the event gets scheduled on
249 */
250 Event(Priority p = Default_Pri)
251 : nextBin(NULL), nextInBin(NULL), _priority(p), flags(Initialized)
252 {
253#ifndef NDEBUG
254 instance = ++instanceCounter;
255 queue = NULL;
256#endif
257#ifdef EVENTQ_DEBUG
258 whenCreated = curTick();
259 whenScheduled = 0;
260#endif
261 }
262
263 virtual ~Event();
264 virtual const std::string name() const;
265
266 /// Return a C string describing the event. This string should
267 /// *not* be dynamically allocated; just a const char array
268 /// describing the event class.
269 virtual const char *description() const;
270
271 /// Dump the current event data
272 void dump() const;
273
274 public:
275 /*
276 * This member function is invoked when the event is processed
277 * (occurs). There is no default implementation; each subclass
278 * must provide its own implementation. The event is not
279 * automatically deleted after it is processed (to allow for
280 * statically allocated event objects).
281 *
282 * If the AutoDestroy flag is set, the object is deleted once it
283 * is processed.
284 */
285 virtual void process() = 0;
286
287 /// Determine if the current event is scheduled
288 bool scheduled() const { return flags.isSet(Scheduled); }
289
290 /// Squash the current event
291 void squash() { flags.set(Squashed); }
292
293 /// Check whether the event is squashed
294 bool squashed() const { return flags.isSet(Squashed); }
295
296 /// See if this is a SimExitEvent (without resorting to RTTI)
297 bool isExitEvent() const { return flags.isSet(IsExitEvent); }
298
299 /// Get the time that the event is scheduled
300 Tick when() const { return _when; }
301
302 /// Get the event priority
303 Priority priority() const { return _priority; }
304
305#ifndef SWIG
306 struct priority_compare
307 : public std::binary_function<Event *, Event *, bool>
308 {
309 bool
310 operator()(const Event *l, const Event *r) const
311 {
312 return l->when() >= r->when() || l->priority() >= r->priority();
313 }
314 };
315
316 virtual void serialize(std::ostream &os);
317 virtual void unserialize(Checkpoint *cp, const std::string &section);
318#endif
319};
320
321#ifndef SWIG
322inline bool
323operator<(const Event &l, const Event &r)
324{
325 return l.when() < r.when() ||
326 (l.when() == r.when() && l.priority() < r.priority());
327}
328
329inline bool
330operator>(const Event &l, const Event &r)
331{
332 return l.when() > r.when() ||
333 (l.when() == r.when() && l.priority() > r.priority());
334}
335
336inline bool
337operator<=(const Event &l, const Event &r)
338{
339 return l.when() < r.when() ||
340 (l.when() == r.when() && l.priority() <= r.priority());
341}
342inline bool
343operator>=(const Event &l, const Event &r)
344{
345 return l.when() > r.when() ||
346 (l.when() == r.when() && l.priority() >= r.priority());
347}
348
349inline bool
350operator==(const Event &l, const Event &r)
351{
352 return l.when() == r.when() && l.priority() == r.priority();
353}
354
355inline bool
356operator!=(const Event &l, const Event &r)
357{
358 return l.when() != r.when() || l.priority() != r.priority();
359}
360#endif
361
362/*
363 * Queue of events sorted in time order
364 */
365class EventQueue : public Serializable
366{
367 private:
368 std::string objName;
369 Event *head;
370
371 void insert(Event *event);
372 void remove(Event *event);
373
374 EventQueue(const EventQueue &);
375 const EventQueue &operator=(const EventQueue &);
376
377 public:
378 EventQueue(const std::string &n);
379
380 virtual const std::string name() const { return objName; }
381
382 // schedule the given event on this queue
383 void schedule(Event *event, Tick when);
384 void deschedule(Event *event);
385 void reschedule(Event *event, Tick when, bool always = false);
386
387 Tick nextTick() const { return head->when(); }
388 Event *serviceOne();
389
390 // process all events up to the given timestamp. we inline a
391 // quick test to see if there are any events to process; if so,
392 // call the internal out-of-line version to process them all.
393 void
394 serviceEvents(Tick when)
395 {
396 while (!empty()) {
397 if (nextTick() > when)
398 break;
399
400 /**
401 * @todo this assert is a good bug catcher. I need to
402 * make it true again.
403 */
404 //assert(head->when() >= when && "event scheduled in the past");
405 serviceOne();
406 }
407 }
408
409 // default: process all events up to 'now' (curTick())
410 void serviceEvents() { serviceEvents(curTick()); }
411
412 // return true if no events are queued
413 bool empty() const { return head == NULL; }
414
415 void dump() const;
416
417 Tick nextEventTime() { return empty() ? curTick() : head->when(); }
418
419 bool debugVerify() const;
420
421#ifndef SWIG
422 virtual void serialize(std::ostream &os);
423 virtual void unserialize(Checkpoint *cp, const std::string &section);
424#endif
425};
426
427#ifndef SWIG
428class EventManager
429{
430 protected:
431 /** A pointer to this object's event queue */
432 EventQueue *eventq;
433
434 public:
435 EventManager(EventManager &em) : eventq(em.queue()) {}
436 EventManager(EventManager *em) : eventq(em ? em->queue() : NULL) {}
437 EventManager(EventQueue *eq) : eventq(eq) {}
438
439 EventQueue *
440 queue() const
441 {
442 return eventq;
443 }
444
445 operator EventQueue *() const
446 {
447 return eventq;
448 }
449
450 void
451 schedule(Event &event, Tick when)
452 {
453 eventq->schedule(&event, when);
454 }
455
456 void
457 deschedule(Event &event)
458 {
459 eventq->deschedule(&event);
460 }
461
462 void
463 reschedule(Event &event, Tick when, bool always = false)
464 {
465 eventq->reschedule(&event, when, always);
466 }
467
468 void
469 schedule(Event *event, Tick when)
470 {
471 eventq->schedule(event, when);
472 }
473
474 void
475 deschedule(Event *event)
476 {
477 eventq->deschedule(event);
478 }
479
480 void
481 reschedule(Event *event, Tick when, bool always = false)
482 {
483 eventq->reschedule(event, when, always);
484 }
485};
486
487inline void
488EventQueue::schedule(Event *event, Tick when)
489{
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());
495
496 event->setWhen(when, this);
497 insert(event);
498 event->flags.set(Event::Scheduled);
499 if (this == &mainEventQueue)
500 event->flags.set(Event::IsMainQueue);
501 else
502 event->flags.clear(Event::IsMainQueue);
503
504 if (DTRACE(Event))
505 event->trace("scheduled");
506}
507
508inline void
509EventQueue::deschedule(Event *event)
510{
511 assert(event->scheduled());
512 assert(event->initialized());
513
514 remove(event);
515
516 event->flags.clear(Event::Squashed);
517 event->flags.clear(Event::Scheduled);
518
519 if (event->flags.isSet(Event::AutoDelete))
520 delete event;
521
522 if (DTRACE(Event))
523 event->trace("descheduled");
524}
525
526inline void
527EventQueue::reschedule(Event *event, Tick when, bool always)
528{
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());
534
535 if (event->scheduled())
536 remove(event);
537
538 event->setWhen(when, this);
539 insert(event);
540 event->flags.clear(Event::Squashed);
541 event->flags.set(Event::Scheduled);
542 if (this == &mainEventQueue)
543 event->flags.set(Event::IsMainQueue);
544 else
545 event->flags.clear(Event::IsMainQueue);
546
547 if (DTRACE(Event))
548 event->trace("rescheduled");
549}
550
551template <class T, void (T::* F)()>
552void
553DelayFunction(EventQueue *eventq, Tick when, T *object)
554{
555 class DelayEvent : public Event
556 {
557 private:
558 T *object;
559
560 public:
561 DelayEvent(T *o)
562 : object(o)
563 { this->setFlags(AutoDelete); }
564 void process() { (object->*F)(); }
565 const char *description() const { return "delay"; }
566 };
567
568 eventq->schedule(new DelayEvent(object), when);
569}
570
571template <class T, void (T::* F)()>
572class EventWrapper : public Event
573{
574 private:
575 T *object;
576
577 public:
578 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
579 : Event(p), object(obj)
580 {
581 if (del)
582 setFlags(AutoDelete);
583 }
584
585 EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
586 : Event(p), object(&obj)
587 {
588 if (del)
589 setFlags(AutoDelete);
590 }
591
592 void process() { (object->*F)(); }
593
594 const std::string
595 name() const
596 {
597 return object->name() + ".wrapped_event";
598 }
599
600 const char *description() const { return "EventWrapped"; }
601};
602#endif
603
604#endif // __SIM_EVENTQ_HH__