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 <assert.h>
40
41#include <algorithm>
42#include <map>
43#include <string>
44#include <vector>
45
46#include "sim/host.hh" // for Tick
47
48#include "base/fast_alloc.hh"
49#include "base/trace.hh"
50#include "sim/serialize.hh"
51
52class EventQueue; // forward declaration
53
54//////////////////////
55//
56// Main Event Queue
57//
58// Events on this queue are processed at the *beginning* of each
59// cycle, before the pipeline simulation is performed.
60//
61// defined in eventq.cc
62//
63//////////////////////
64extern EventQueue mainEventQueue;
65
66
67/*
68 * An item on an event queue. The action caused by a given
69 * event is specified by deriving a subclass and overriding the
70 * process() member function.
71 */
72class Event : public Serializable, public FastAlloc
73{
74 friend class EventQueue;
75
76 private:
77 /// queue to which this event belongs (though it may or may not be
78 /// scheduled on this queue yet)
79 EventQueue *queue;
80
81 Event *next;
82
83 Tick _when; //!< timestamp when event should be processed
84 int _priority; //!< event priority
85 char _flags;
86
87 protected:
88 enum Flags {
89 None = 0x0,
90 Squashed = 0x1,
91 Scheduled = 0x2,
92 AutoDelete = 0x4,
93 AutoSerialize = 0x8
94 };
95
96 bool getFlags(Flags f) const { return (_flags & f) == f; }
97 void setFlags(Flags f) { _flags |= f; }
98 void clearFlags(Flags f) { _flags &= ~f; }
99
100 protected:
101 EventQueue *theQueue() const { return queue; }
102
103#if TRACING_ON
104 Tick when_created; //!< Keep track of creation time For debugging
105 Tick when_scheduled; //!< Keep track of creation time For debugging
106
107 virtual void trace(const char *action); //!< trace event activity
108#else
109 void trace(const char *) {}
110#endif
111
112 unsigned annotated_value;
113
114 public:
115
116 /// Event priorities, to provide tie-breakers for events scheduled
117 /// at the same cycle. Most events are scheduled at the default
118 /// priority; these values are used to control events that need to
119 /// be ordered within a cycle.
120 enum Priority {
121 /// Breakpoints should happen before anything else, so we
122 /// don't miss any action when debugging.
123 Debug_Break_Pri = -100,
124
125 /// For some reason "delayed" inter-cluster writebacks are
126 /// scheduled before regular writebacks (which have default
127 /// priority). Steve?
128 Delayed_Writeback_Pri = -1,
129
130 /// Default is zero for historical reasons.
131 Default_Pri = 0,
132
133 /// CPU switches schedule the new CPU's tick event for the
134 /// same cycle (after unscheduling the old CPU's tick event).
135 /// The switch needs to come before any tick events to make
136 /// sure we don't tick both CPUs in the same cycle.
137 CPU_Switch_Pri = 31,
138
139 /// Serailization needs to occur before tick events also, so
140 /// that a serialize/unserialize is identical to an on-line
141 /// CPU switch.
142 Serialize_Pri = 32,
143
144 /// CPU ticks must come after other associated CPU events
145 /// (such as writebacks).
146 CPU_Tick_Pri = 50,
147
148 /// Statistics events (dump, reset, etc.) come after
149 /// everything else, but before exit.
150 Stat_Event_Pri = 90,
151
152 /// If we want to exit on this cycle, it's the very last thing
153 /// we do.
154 Sim_Exit_Pri = 100
155 };
156
157 /*
158 * Event constructor
159 * @param queue that the event gets scheduled on
160 */
161 Event(EventQueue *q, Priority p = Default_Pri)
162 : queue(q), next(NULL), _priority(p), _flags(None),
163#if TRACING_ON
164 when_created(curTick), when_scheduled(0),
165#endif
166 annotated_value(0)
167 {
168 }
169
170 ~Event() {}
171
172 virtual const std::string name() const {
173 return csprintf("Event_%x", (uintptr_t)this);
174 }
175
176 /// Determine if the current event is scheduled
177 bool scheduled() const { return getFlags(Scheduled); }
178
179 /// Schedule the event with the current priority or default priority
180 void schedule(Tick t);
181
182 /// Reschedule the event with the current priority
183 void reschedule(Tick t);
184
185 /// Remove the event from the current schedule
186 void deschedule();
187
188 /// Return a C string describing the event. This string should
189 /// *not* be dynamically allocated; just a const char array
190 /// describing the event class.
191 virtual const char *description();
192
193 /// Dump the current event data
194 void dump();
195
196 /*
197 * This member function is invoked when the event is processed
198 * (occurs). There is no default implementation; each subclass
199 * must provide its own implementation. The event is not
200 * automatically deleted after it is processed (to allow for
201 * statically allocated event objects).
202 *
203 * If the AutoDestroy flag is set, the object is deleted once it
204 * is processed.
205 */
206 virtual void process() = 0;
207
208 void annotate(unsigned value) { annotated_value = value; };
209 unsigned annotation() { return annotated_value; }
210
211 /// Squash the current event
212 void squash() { setFlags(Squashed); }
213
214 /// Check whether the event is squashed
215 bool squashed() { return getFlags(Squashed); }
216
217 /// Get the time that the event is scheduled
218 Tick when() const { return _when; }
219
220 /// Get the event priority
221 int priority() const { return _priority; }
222
223 struct priority_compare :
224 public std::binary_function<Event *, Event *, bool>
225 {
226 bool operator()(const Event *l, const Event *r) const {
227 return l->when() >= r->when() || l->priority() >= r->priority();
228 }
229 };
230
231 virtual void serialize(std::ostream &os);
232 virtual void unserialize(Checkpoint *cp, const std::string &section);
233};
234
235template <class T, void (T::* F)()>
236void
237DelayFunction(Tick when, T *object)
238{
239 class DelayEvent : public Event
240 {
241 private:
242 T *object;
243
244 public:
245 DelayEvent(Tick when, T *o)
246 : Event(&mainEventQueue), object(o)
247 { setFlags(this->AutoDestroy); schedule(when); }
248 void process() { (object->*F)(); }
249 const char *description() { return "delay"; }
250 };
251
252 new DelayEvent(when, object);
253}
254
255template <class T, void (T::* F)()>
256class EventWrapper : public Event
257{
258 private:
259 T *object;
260
261 public:
262 EventWrapper(T *obj, bool del = false, EventQueue *q = &mainEventQueue,
263 Priority p = Default_Pri)
264 : Event(q, p), object(obj)
265 {
266 if (del)
267 setFlags(AutoDelete);
268 }
269 void process() { (object->*F)(); }
270};
271
272/*
273 * Queue of events sorted in time order
274 */
275class EventQueue : public Serializable
276{
277 protected:
278 std::string objName;
279
280 private:
281 Event *head;
282
283 void insert(Event *event);
284 void remove(Event *event);
285
286 public:
287
288 // constructor
289 EventQueue(const std::string &n)
290 : objName(n), head(NULL)
291 {}
292
293 virtual const std::string name() const { return objName; }
294
295 // schedule the given event on this queue
296 void schedule(Event *ev);
297 void deschedule(Event *ev);
298 void reschedule(Event *ev);
299
300 Tick nextTick() { return head->when(); }
301 void serviceOne();
302
303 // process all events up to the given timestamp. we inline a
304 // quick test to see if there are any events to process; if so,
305 // call the internal out-of-line version to process them all.
306 void serviceEvents(Tick when) {
307 while (!empty()) {
308 if (nextTick() > when)
309 break;
310
311 /**
312 * @todo this assert is a good bug catcher. I need to
313 * make it true again.
314 */
315 //assert(head->when() >= when && "event scheduled in the past");
316 serviceOne();
317 }
318 }
319
320 // default: process all events up to 'now' (curTick)
321 void serviceEvents() { serviceEvents(curTick); }
322
323 // return true if no events are queued
324 bool empty() { return head == NULL; }
325
326 void dump();
327
328 Tick nextEventTime() { return empty() ? curTick : head->when(); }
329
330 virtual void serialize(std::ostream &os);
331 virtual void unserialize(Checkpoint *cp, const std::string &section);
332};
333
334
335//////////////////////
336//
337// inline functions
338//
339// can't put these inside declaration due to circular dependence
340// between Event and EventQueue classes.
341//
342//////////////////////
343
344// schedule at specified time (place on event queue specified via
345// constructor)
346inline void
347Event::schedule(Tick t)
348{
349 assert(!scheduled());
350 assert(t >= curTick);
351
352 setFlags(Scheduled);
353#if TRACING_ON
354 when_scheduled = curTick;
355#endif
356 _when = t;
357 queue->schedule(this);
358}
359
360inline void
361Event::deschedule()
362{
363 assert(scheduled());
364
365 clearFlags(Squashed);
366 clearFlags(Scheduled);
367 queue->deschedule(this);
368}
369
370inline void
371Event::reschedule(Tick t)
372{
373 assert(scheduled());
374 clearFlags(Squashed);
375
376#if TRACING_ON
377 when_scheduled = curTick;
378#endif
379 _when = t;
380 queue->reschedule(this);
381}
382
383inline void
384EventQueue::schedule(Event *event)
385{
386 insert(event);
387 if (DTRACE(Event))
388 event->trace("scheduled");
389}
390
391inline void
392EventQueue::deschedule(Event *event)
393{
394 remove(event);
395 if (DTRACE(Event))
396 event->trace("descheduled");
397}
398
399inline void
400EventQueue::reschedule(Event *event)
401{
402 remove(event);
403 insert(event);
404 if (DTRACE(Event))
405 event->trace("rescheduled");
406}
407
408
409
410#endif // __SIM_EVENTQ_HH__