eventq.hh revision 2632:1bb2f91485ea
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
29/* @file
30 * EventQueue interfaces
31 */
32
33#ifndef __SIM_EVENTQ_HH__
34#define __SIM_EVENTQ_HH__
35
36#include <assert.h>
37
38#include <algorithm>
39#include <map>
40#include <string>
41#include <vector>
42
43#include "sim/host.hh"	// for Tick
44
45#include "base/fast_alloc.hh"
46#include "base/trace.hh"
47#include "sim/serialize.hh"
48
49class EventQueue;	// forward declaration
50
51//////////////////////
52//
53// Main Event Queue
54//
55// Events on this queue are processed at the *beginning* of each
56// cycle, before the pipeline simulation is performed.
57//
58// defined in eventq.cc
59//
60//////////////////////
61extern EventQueue mainEventQueue;
62
63
64/*
65 * An item on an event queue.  The action caused by a given
66 * event is specified by deriving a subclass and overriding the
67 * process() member function.
68 */
69class Event : public Serializable, public FastAlloc
70{
71    friend class EventQueue;
72
73  private:
74    /// queue to which this event belongs (though it may or may not be
75    /// scheduled on this queue yet)
76    EventQueue *queue;
77
78    Event *next;
79
80    Tick _when;	//!< timestamp when event should be processed
81    int _priority;	//!< event priority
82    char _flags;
83
84  protected:
85    enum Flags {
86        None = 0x0,
87        Squashed = 0x1,
88        Scheduled = 0x2,
89        AutoDelete = 0x4,
90        AutoSerialize = 0x8
91    };
92
93    bool getFlags(Flags f) const { return (_flags & f) == f; }
94    void setFlags(Flags f) { _flags |= f; }
95    void clearFlags(Flags f) { _flags &= ~f; }
96
97  protected:
98    EventQueue *theQueue() const { return queue; }
99
100#if TRACING_ON
101    Tick when_created;	//!< Keep track of creation time For debugging
102    Tick when_scheduled;	//!< Keep track of creation time For debugging
103
104    virtual void trace(const char *action);	//!< trace event activity
105#else
106    void trace(const char *) {}
107#endif
108
109    unsigned annotated_value;
110
111  public:
112
113    /// Event priorities, to provide tie-breakers for events scheduled
114    /// at the same cycle.  Most events are scheduled at the default
115    /// priority; these values are used to control events that need to
116    /// be ordered within a cycle.
117    enum Priority {
118        /// Breakpoints should happen before anything else, so we
119        /// don't miss any action when debugging.
120        Debug_Break_Pri		= -100,
121
122        /// For some reason "delayed" inter-cluster writebacks are
123        /// scheduled before regular writebacks (which have default
124        /// priority).  Steve?
125        Delayed_Writeback_Pri	=   -1,
126
127        /// Default is zero for historical reasons.
128        Default_Pri		=    0,
129
130        /// CPU switches schedule the new CPU's tick event for the
131        /// same cycle (after unscheduling the old CPU's tick event).
132        /// The switch needs to come before any tick events to make
133        /// sure we don't tick both CPUs in the same cycle.
134        CPU_Switch_Pri		=   31,
135
136        /// Serailization needs to occur before tick events also, so
137        /// that a serialize/unserialize is identical to an on-line
138        /// CPU switch.
139        Serialize_Pri		=   32,
140
141        /// CPU ticks must come after other associated CPU events
142        /// (such as writebacks).
143        CPU_Tick_Pri		=   50,
144
145        /// Statistics events (dump, reset, etc.) come after
146        /// everything else, but before exit.
147        Stat_Event_Pri		=   90,
148
149        /// If we want to exit on this cycle, it's the very last thing
150        /// we do.
151        Sim_Exit_Pri		=  100
152    };
153
154    /*
155     * Event constructor
156     * @param queue that the event gets scheduled on
157     */
158    Event(EventQueue *q, Priority p = Default_Pri)
159        : queue(q), next(NULL), _priority(p), _flags(None),
160#if TRACING_ON
161          when_created(curTick), when_scheduled(0),
162#endif
163          annotated_value(0)
164    {
165    }
166
167    ~Event() {}
168
169    virtual const std::string name() const {
170        return csprintf("Event_%x", (uintptr_t)this);
171    }
172
173    /// Determine if the current event is scheduled
174    bool scheduled() const { return getFlags(Scheduled); }
175
176    /// Schedule the event with the current priority or default priority
177    void schedule(Tick t);
178
179    /// Reschedule the event with the current priority
180    void reschedule(Tick t);
181
182    /// Remove the event from the current schedule
183    void deschedule();
184
185    /// Return a C string describing the event.  This string should
186    /// *not* be dynamically allocated; just a const char array
187    /// describing the event class.
188    virtual const char *description();
189
190    /// Dump the current event data
191    void dump();
192
193    /*
194     * This member function is invoked when the event is processed
195     * (occurs).  There is no default implementation; each subclass
196     * must provide its own implementation.  The event is not
197     * automatically deleted after it is processed (to allow for
198     * statically allocated event objects).
199     *
200     * If the AutoDestroy flag is set, the object is deleted once it
201     * is processed.
202     */
203    virtual void process() = 0;
204
205    void annotate(unsigned value) { annotated_value = value; };
206    unsigned annotation() { return annotated_value; }
207
208    /// Squash the current event
209    void squash() { setFlags(Squashed); }
210
211    /// Check whether the event is squashed
212    bool squashed() { return getFlags(Squashed); }
213
214    /// Get the time that the event is scheduled
215    Tick when() const { return _when; }
216
217    /// Get the event priority
218    int priority() const { return _priority; }
219
220    struct priority_compare :
221    public std::binary_function<Event *, Event *, bool>
222    {
223        bool operator()(const Event *l, const Event *r) const {
224            return l->when() >= r->when() || l->priority() >= r->priority();
225        }
226    };
227
228    virtual void serialize(std::ostream &os);
229    virtual void unserialize(Checkpoint *cp, const std::string &section);
230};
231
232template <class T, void (T::* F)()>
233void
234DelayFunction(Tick when, T *object)
235{
236    class DelayEvent : public Event
237    {
238      private:
239        T *object;
240
241      public:
242        DelayEvent(Tick when, T *o)
243            : Event(&mainEventQueue), object(o)
244            { setFlags(this->AutoDestroy); schedule(when); }
245        void process() { (object->*F)(); }
246        const char *description() { return "delay"; }
247    };
248
249    new DelayEvent(when, object);
250}
251
252template <class T, void (T::* F)()>
253class EventWrapper : public Event
254{
255  private:
256    T *object;
257
258  public:
259    EventWrapper(T *obj, bool del = false, EventQueue *q = &mainEventQueue,
260                 Priority p = Default_Pri)
261        : Event(q, p), object(obj)
262    {
263        if (del)
264            setFlags(AutoDelete);
265    }
266    void process() { (object->*F)(); }
267};
268
269/*
270 * Queue of events sorted in time order
271 */
272class EventQueue : public Serializable
273{
274  protected:
275    std::string objName;
276
277  private:
278    Event *head;
279
280    void insert(Event *event);
281    void remove(Event *event);
282
283  public:
284
285    // constructor
286    EventQueue(const std::string &n)
287        : objName(n), head(NULL)
288    {}
289
290    virtual const std::string name() const { return objName; }
291
292    // schedule the given event on this queue
293    void schedule(Event *ev);
294    void deschedule(Event *ev);
295    void reschedule(Event *ev);
296
297    Tick nextTick() { return head->when(); }
298    void serviceOne();
299
300    // process all events up to the given timestamp.  we inline a
301    // quick test to see if there are any events to process; if so,
302    // call the internal out-of-line version to process them all.
303    void serviceEvents(Tick when) {
304        while (!empty()) {
305            if (nextTick() > when)
306                break;
307
308            /**
309             * @todo this assert is a good bug catcher.  I need to
310             * make it true again.
311             */
312            //assert(head->when() >= when && "event scheduled in the past");
313            serviceOne();
314        }
315    }
316
317    // default: process all events up to 'now' (curTick)
318    void serviceEvents() { serviceEvents(curTick); }
319
320    // return true if no events are queued
321    bool empty() { return head == NULL; }
322
323    void dump();
324
325    Tick nextEventTime() { return empty() ? curTick : head->when(); }
326
327    virtual void serialize(std::ostream &os);
328    virtual void unserialize(Checkpoint *cp, const std::string &section);
329};
330
331
332//////////////////////
333//
334// inline functions
335//
336// can't put these inside declaration due to circular dependence
337// between Event and EventQueue classes.
338//
339//////////////////////
340
341// schedule at specified time (place on event queue specified via
342// constructor)
343inline void
344Event::schedule(Tick t)
345{
346    assert(!scheduled());
347    assert(t >= curTick);
348
349    setFlags(Scheduled);
350#if TRACING_ON
351    when_scheduled = curTick;
352#endif
353    _when = t;
354    queue->schedule(this);
355}
356
357inline void
358Event::deschedule()
359{
360    assert(scheduled());
361
362    clearFlags(Squashed);
363    clearFlags(Scheduled);
364    queue->deschedule(this);
365}
366
367inline void
368Event::reschedule(Tick t)
369{
370    assert(scheduled());
371    clearFlags(Squashed);
372
373#if TRACING_ON
374    when_scheduled = curTick;
375#endif
376    _when = t;
377    queue->reschedule(this);
378}
379
380inline void
381EventQueue::schedule(Event *event)
382{
383    insert(event);
384    if (DTRACE(Event))
385        event->trace("scheduled");
386}
387
388inline void
389EventQueue::deschedule(Event *event)
390{
391    remove(event);
392    if (DTRACE(Event))
393        event->trace("descheduled");
394}
395
396inline void
397EventQueue::reschedule(Event *event)
398{
399    remove(event);
400    insert(event);
401    if (DTRACE(Event))
402        event->trace("rescheduled");
403}
404
405
406
407#endif // __SIM_EVENTQ_HH__
408