eventq.hh revision 7823:dac01f14f20f
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; // public readable flags
72    static const FlagsType PublicWrite   = 0x001d; // public writable flags
73    static const FlagsType Squashed      = 0x0001; // has been squashed
74    static const FlagsType Scheduled     = 0x0002; // has been scheduled
75    static const FlagsType AutoDelete    = 0x0004; // delete after dispatch
76    static const FlagsType AutoSerialize = 0x0008; // must be serialized
77    static const FlagsType IsExitEvent   = 0x0010; // special exit event
78    static const FlagsType IsMainQueue   = 0x0020; // on main event queue
79    static const FlagsType Initialized   = 0x7a40; // somewhat random bits
80    static const FlagsType InitMask      = 0xffc0; // mask for init bits
81
82    bool
83    initialized() const
84    {
85        return this && (flags & InitMask) == Initialized;
86    }
87
88  public:
89    typedef int8_t Priority;
90
91  private:
92    // The event queue is now a linked list of linked lists.  The
93    // 'nextBin' pointer is to find the bin, where a bin is defined as
94    // when+priority.  All events in the same bin will be stored in a
95    // second linked list (a stack) maintained by the 'nextInBin'
96    // pointer.  The list will be accessed in LIFO order.  The end
97    // result is that the insert/removal in 'nextBin' is
98    // linear/constant, and the lookup/removal in 'nextInBin' is
99    // constant/constant.  Hopefully this is a significant improvement
100    // over the current fully linear insertion.
101    Event *nextBin;
102    Event *nextInBin;
103
104    static Event *insertBefore(Event *event, Event *curr);
105    static Event *removeItem(Event *event, Event *last);
106
107    Tick _when;         //!< timestamp when event should be processed
108    Priority _priority; //!< event priority
109    Flags flags;
110
111#ifndef NDEBUG
112    /// Global counter to generate unique IDs for Event instances
113    static Counter instanceCounter;
114
115    /// This event's unique ID.  We can also use pointer values for
116    /// this but they're not consistent across runs making debugging
117    /// more difficult.  Thus we use a global counter value when
118    /// debugging.
119    Counter instance;
120
121    /// queue to which this event belongs (though it may or may not be
122    /// scheduled on this queue yet)
123    EventQueue *queue;
124#endif
125
126#ifdef EVENTQ_DEBUG
127    Tick whenCreated;   //!< time created
128    Tick whenScheduled; //!< time scheduled
129#endif
130
131    void
132    setWhen(Tick when, EventQueue *q)
133    {
134        _when = when;
135#ifndef NDEBUG
136        queue = q;
137#endif
138#ifdef EVENTQ_DEBUG
139        whenScheduled = curTick();
140#endif
141    }
142
143  protected:
144    /// Accessor for flags.
145    Flags
146    getFlags() const
147    {
148        return flags & PublicRead;
149    }
150
151    Flags
152    getFlags(Flags _flags) const
153    {
154        assert(_flags.noneSet(~PublicRead));
155        return flags.isSet(_flags);
156    }
157
158    Flags
159    allFlags(Flags _flags) const
160    {
161        assert(_flags.noneSet(~PublicRead));
162        return flags.allSet(_flags);
163    }
164
165    /// Accessor for flags.
166    void
167    setFlags(Flags _flags)
168    {
169        assert(_flags.noneSet(~PublicWrite));
170        flags.set(_flags);
171    }
172
173    void
174    clearFlags(Flags _flags)
175    {
176        assert(_flags.noneSet(~PublicWrite));
177        flags.clear(_flags);
178    }
179
180    void
181    clearFlags()
182    {
183        flags.clear(PublicWrite);
184    }
185
186    // This function isn't really useful if TRACING_ON is not defined
187    virtual void trace(const char *action);     //!< trace event activity
188
189  public:
190    /// Event priorities, to provide tie-breakers for events scheduled
191    /// at the same cycle.  Most events are scheduled at the default
192    /// priority; these values are used to control events that need to
193    /// be ordered within a cycle.
194
195    /// Minimum priority
196    static const Priority Minimum_Pri =          SCHAR_MIN;
197
198    /// If we enable tracing on a particular cycle, do that as the
199    /// very first thing so we don't miss any of the events on
200    /// that cycle (even if we enter the debugger).
201    static const Priority Trace_Enable_Pri =          -101;
202
203    /// Breakpoints should happen before anything else (except
204    /// enabling trace output), so we don't miss any action when
205    /// debugging.
206    static const Priority Debug_Break_Pri =           -100;
207
208    /// CPU switches schedule the new CPU's tick event for the
209    /// same cycle (after unscheduling the old CPU's tick event).
210    /// The switch needs to come before any tick events to make
211    /// sure we don't tick both CPUs in the same cycle.
212    static const Priority CPU_Switch_Pri =             -31;
213
214    /// For some reason "delayed" inter-cluster writebacks are
215    /// scheduled before regular writebacks (which have default
216    /// priority).  Steve?
217    static const Priority Delayed_Writeback_Pri =       -1;
218
219    /// Default is zero for historical reasons.
220    static const Priority Default_Pri =                  0;
221
222    /// Serailization needs to occur before tick events also, so
223    /// that a serialize/unserialize is identical to an on-line
224    /// CPU switch.
225    static const Priority Serialize_Pri =               32;
226
227    /// CPU ticks must come after other associated CPU events
228    /// (such as writebacks).
229    static const Priority CPU_Tick_Pri =                50;
230
231    /// Statistics events (dump, reset, etc.) come after
232    /// everything else, but before exit.
233    static const Priority Stat_Event_Pri =              90;
234
235    /// Progress events come at the end.
236    static const Priority Progress_Event_Pri =          95;
237
238    /// If we want to exit on this cycle, it's the very last thing
239    /// we do.
240    static const Priority Sim_Exit_Pri =               100;
241
242    /// Maximum priority
243    static const Priority Maximum_Pri =          SCHAR_MAX;
244
245    /*
246     * Event constructor
247     * @param queue that the event gets scheduled on
248     */
249    Event(Priority p = Default_Pri)
250        : nextBin(NULL), nextInBin(NULL), _priority(p), flags(Initialized)
251    {
252#ifndef NDEBUG
253        instance = ++instanceCounter;
254        queue = NULL;
255#endif
256#ifdef EVENTQ_DEBUG
257        whenCreated = curTick();
258        whenScheduled = 0;
259#endif
260    }
261
262    virtual ~Event();
263    virtual const std::string name() const;
264
265    /// Return a C string describing the event.  This string should
266    /// *not* be dynamically allocated; just a const char array
267    /// describing the event class.
268    virtual const char *description() const;
269
270    /// Dump the current event data
271    void dump() const;
272
273  public:
274    /*
275     * This member function is invoked when the event is processed
276     * (occurs).  There is no default implementation; each subclass
277     * must provide its own implementation.  The event is not
278     * automatically deleted after it is processed (to allow for
279     * statically allocated event objects).
280     *
281     * If the AutoDestroy flag is set, the object is deleted once it
282     * is processed.
283     */
284    virtual void process() = 0;
285
286    /// Determine if the current event is scheduled
287    bool scheduled() const { return flags.isSet(Scheduled); }
288
289    /// Squash the current event
290    void squash() { flags.set(Squashed); }
291
292    /// Check whether the event is squashed
293    bool squashed() const { return flags.isSet(Squashed); }
294
295    /// See if this is a SimExitEvent (without resorting to RTTI)
296    bool isExitEvent() const { return flags.isSet(IsExitEvent); }
297
298    /// Get the time that the event is scheduled
299    Tick when() const { return _when; }
300
301    /// Get the event priority
302    Priority priority() const { return _priority; }
303
304#ifndef SWIG
305    struct priority_compare
306        : public std::binary_function<Event *, Event *, bool>
307    {
308        bool
309        operator()(const Event *l, const Event *r) const
310        {
311            return l->when() >= r->when() || l->priority() >= r->priority();
312        }
313    };
314
315    virtual void serialize(std::ostream &os);
316    virtual void unserialize(Checkpoint *cp, const std::string &section);
317#endif
318};
319
320#ifndef SWIG
321inline bool
322operator<(const Event &l, const Event &r)
323{
324    return l.when() < r.when() ||
325        (l.when() == r.when() && l.priority() < r.priority());
326}
327
328inline bool
329operator>(const Event &l, const Event &r)
330{
331    return l.when() > r.when() ||
332        (l.when() == r.when() && l.priority() > r.priority());
333}
334
335inline bool
336operator<=(const Event &l, const Event &r)
337{
338    return l.when() < r.when() ||
339        (l.when() == r.when() && l.priority() <= r.priority());
340}
341inline bool
342operator>=(const Event &l, const Event &r)
343{
344    return l.when() > r.when() ||
345        (l.when() == r.when() && l.priority() >= r.priority());
346}
347
348inline bool
349operator==(const Event &l, const Event &r)
350{
351    return l.when() == r.when() && l.priority() == r.priority();
352}
353
354inline bool
355operator!=(const Event &l, const Event &r)
356{
357    return l.when() != r.when() || l.priority() != r.priority();
358}
359#endif
360
361/*
362 * Queue of events sorted in time order
363 */
364class EventQueue : public Serializable
365{
366  private:
367    std::string objName;
368    Event *head;
369
370    void insert(Event *event);
371    void remove(Event *event);
372
373    EventQueue(const EventQueue &);
374    const EventQueue &operator=(const EventQueue &);
375
376  public:
377    EventQueue(const std::string &n);
378
379    virtual const std::string name() const { return objName; }
380
381    // schedule the given event on this queue
382    void schedule(Event *event, Tick when);
383    void deschedule(Event *event);
384    void reschedule(Event *event, Tick when, bool always = false);
385
386    Tick nextTick() const { return head->when(); }
387    Event *serviceOne();
388
389    // process all events up to the given timestamp.  we inline a
390    // quick test to see if there are any events to process; if so,
391    // call the internal out-of-line version to process them all.
392    void
393    serviceEvents(Tick when)
394    {
395        while (!empty()) {
396            if (nextTick() > when)
397                break;
398
399            /**
400             * @todo this assert is a good bug catcher.  I need to
401             * make it true again.
402             */
403            //assert(head->when() >= when && "event scheduled in the past");
404            serviceOne();
405        }
406    }
407
408    // default: process all events up to 'now' (curTick())
409    void serviceEvents() { serviceEvents(curTick()); }
410
411    // return true if no events are queued
412    bool empty() const { return head == NULL; }
413
414    void dump() const;
415
416    Tick nextEventTime() { return empty() ? curTick() : head->when(); }
417
418    bool debugVerify() const;
419
420#ifndef SWIG
421    virtual void serialize(std::ostream &os);
422    virtual void unserialize(Checkpoint *cp, const std::string &section);
423#endif
424};
425
426#ifndef SWIG
427class EventManager
428{
429  protected:
430    /** A pointer to this object's event queue */
431    EventQueue *eventq;
432
433  public:
434    EventManager(EventManager &em) : eventq(em.queue()) {}
435    EventManager(EventManager *em) : eventq(em ? em->queue() : NULL) {}
436    EventManager(EventQueue *eq) : eventq(eq) {}
437
438    EventQueue *
439    queue() const
440    {
441        return eventq;
442    }
443
444    operator EventQueue *() const
445    {
446        return eventq;
447    }
448
449    void
450    schedule(Event &event, Tick when)
451    {
452        eventq->schedule(&event, when);
453    }
454
455    void
456    deschedule(Event &event)
457    {
458        eventq->deschedule(&event);
459    }
460
461    void
462    reschedule(Event &event, Tick when, bool always = false)
463    {
464        eventq->reschedule(&event, when, always);
465    }
466
467    void
468    schedule(Event *event, Tick when)
469    {
470        eventq->schedule(event, when);
471    }
472
473    void
474    deschedule(Event *event)
475    {
476        eventq->deschedule(event);
477    }
478
479    void
480    reschedule(Event *event, Tick when, bool always = false)
481    {
482        eventq->reschedule(event, when, always);
483    }
484};
485
486inline void
487EventQueue::schedule(Event *event, Tick when)
488{
489    assert((UTick)when >= (UTick)curTick());
490    assert(!event->scheduled());
491    assert(event->initialized());
492
493    event->setWhen(when, this);
494    insert(event);
495    event->flags.set(Event::Scheduled);
496    if (this == &mainEventQueue)
497        event->flags.set(Event::IsMainQueue);
498    else
499        event->flags.clear(Event::IsMainQueue);
500
501    if (DTRACE(Event))
502        event->trace("scheduled");
503}
504
505inline void
506EventQueue::deschedule(Event *event)
507{
508    assert(event->scheduled());
509    assert(event->initialized());
510
511    remove(event);
512
513    event->flags.clear(Event::Squashed);
514    event->flags.clear(Event::Scheduled);
515
516    if (event->flags.isSet(Event::AutoDelete))
517        delete event;
518
519    if (DTRACE(Event))
520        event->trace("descheduled");
521}
522
523inline void
524EventQueue::reschedule(Event *event, Tick when, bool always)
525{
526    assert(when >= curTick());
527    assert(always || event->scheduled());
528    assert(event->initialized());
529
530    if (event->scheduled())
531        remove(event);
532
533    event->setWhen(when, this);
534    insert(event);
535    event->flags.clear(Event::Squashed);
536    event->flags.set(Event::Scheduled);
537    if (this == &mainEventQueue)
538        event->flags.set(Event::IsMainQueue);
539    else
540        event->flags.clear(Event::IsMainQueue);
541
542    if (DTRACE(Event))
543        event->trace("rescheduled");
544}
545
546template <class T, void (T::* F)()>
547void
548DelayFunction(EventQueue *eventq, Tick when, T *object)
549{
550    class DelayEvent : public Event
551    {
552      private:
553        T *object;
554
555      public:
556        DelayEvent(T *o)
557            : object(o)
558        { this->setFlags(AutoDelete); }
559        void process() { (object->*F)(); }
560        const char *description() const { return "delay"; }
561    };
562
563    eventq->schedule(new DelayEvent(object), when);
564}
565
566template <class T, void (T::* F)()>
567class EventWrapper : public Event
568{
569  private:
570    T *object;
571
572  public:
573    EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
574        : Event(p), object(obj)
575    {
576        if (del)
577            setFlags(AutoDelete);
578    }
579
580    EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
581        : Event(p), object(&obj)
582    {
583        if (del)
584            setFlags(AutoDelete);
585    }
586
587    void process() { (object->*F)(); }
588
589    const std::string
590    name() const
591    {
592        return object->name() + ".wrapped_event";
593    }
594
595    const char *description() const { return "EventWrapped"; }
596};
597#endif
598
599#endif // __SIM_EVENTQ_HH__
600