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__