eventq.hh (11800:54436a1784dc) eventq.hh (11990:5fad911cc326)
1/*
2 * Copyright (c) 2000-2005 The Regents of The University of Michigan
3 * Copyright (c) 2013 Advanced Micro Devices, Inc.
4 * Copyright (c) 2013 Mark D. Hill and David A. Wood
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
9 * met: redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer;
11 * redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution;
14 * neither the name of the copyright holders nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * Authors: Steve Reinhardt
31 * Nathan Binkert
32 */
33
34/* @file
35 * EventQueue interfaces
36 */
37
38#ifndef __SIM_EVENTQ_HH__
39#define __SIM_EVENTQ_HH__
40
41#include <algorithm>
42#include <cassert>
43#include <climits>
44#include <iosfwd>
45#include <memory>
46#include <mutex>
47#include <string>
48
49#include "base/flags.hh"
50#include "base/types.hh"
51#include "debug/Event.hh"
52#include "sim/serialize.hh"
53
54class EventQueue; // forward declaration
55class BaseGlobalEvent;
56
57//! Simulation Quantum for multiple eventq simulation.
58//! The quantum value is the period length after which the queues
59//! synchronize themselves with each other. This means that any
60//! event to scheduled on Queue A which is generated by an event on
61//! Queue B should be at least simQuantum ticks away in future.
62extern Tick simQuantum;
63
64//! Current number of allocated main event queues.
65extern uint32_t numMainEventQueues;
66
67//! Array for main event queues.
68extern std::vector<EventQueue *> mainEventQueue;
69
1/*
2 * Copyright (c) 2000-2005 The Regents of The University of Michigan
3 * Copyright (c) 2013 Advanced Micro Devices, Inc.
4 * Copyright (c) 2013 Mark D. Hill and David A. Wood
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
9 * met: redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer;
11 * redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution;
14 * neither the name of the copyright holders nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * Authors: Steve Reinhardt
31 * Nathan Binkert
32 */
33
34/* @file
35 * EventQueue interfaces
36 */
37
38#ifndef __SIM_EVENTQ_HH__
39#define __SIM_EVENTQ_HH__
40
41#include <algorithm>
42#include <cassert>
43#include <climits>
44#include <iosfwd>
45#include <memory>
46#include <mutex>
47#include <string>
48
49#include "base/flags.hh"
50#include "base/types.hh"
51#include "debug/Event.hh"
52#include "sim/serialize.hh"
53
54class EventQueue; // forward declaration
55class BaseGlobalEvent;
56
57//! Simulation Quantum for multiple eventq simulation.
58//! The quantum value is the period length after which the queues
59//! synchronize themselves with each other. This means that any
60//! event to scheduled on Queue A which is generated by an event on
61//! Queue B should be at least simQuantum ticks away in future.
62extern Tick simQuantum;
63
64//! Current number of allocated main event queues.
65extern uint32_t numMainEventQueues;
66
67//! Array for main event queues.
68extern std::vector<EventQueue *> mainEventQueue;
69
70#ifndef SWIG
71//! The current event queue for the running thread. Access to this queue
72//! does not require any locking from the thread.
73
74extern __thread EventQueue *_curEventQueue;
75
70//! The current event queue for the running thread. Access to this queue
71//! does not require any locking from the thread.
72
73extern __thread EventQueue *_curEventQueue;
74
76#endif
77
78//! Current mode of execution: parallel / serial
79extern bool inParallelMode;
80
81//! Function for returning eventq queue for the provided
82//! index. The function allocates a new queue in case one
83//! does not exist for the index, provided that the index
84//! is with in bounds.
85EventQueue *getEventQueue(uint32_t index);
86
87inline EventQueue *curEventQueue() { return _curEventQueue; }
88inline void curEventQueue(EventQueue *q) { _curEventQueue = q; }
89
90/**
91 * Common base class for Event and GlobalEvent, so they can share flag
92 * and priority definitions and accessor functions. This class should
93 * not be used directly.
94 */
95class EventBase
96{
97 protected:
98 typedef unsigned short FlagsType;
99 typedef ::Flags<FlagsType> Flags;
100
101 static const FlagsType PublicRead = 0x003f; // public readable flags
102 static const FlagsType PublicWrite = 0x001d; // public writable flags
103 static const FlagsType Squashed = 0x0001; // has been squashed
104 static const FlagsType Scheduled = 0x0002; // has been scheduled
105 static const FlagsType AutoDelete = 0x0004; // delete after dispatch
106 /**
107 * This used to be AutoSerialize. This value can't be reused
108 * without changing the checkpoint version since the flag field
109 * gets serialized.
110 */
111 static const FlagsType Reserved0 = 0x0008;
112 static const FlagsType IsExitEvent = 0x0010; // special exit event
113 static const FlagsType IsMainQueue = 0x0020; // on main event queue
114 static const FlagsType Initialized = 0x7a40; // somewhat random bits
115 static const FlagsType InitMask = 0xffc0; // mask for init bits
116
117 public:
118 typedef int8_t Priority;
119
120 /// Event priorities, to provide tie-breakers for events scheduled
121 /// at the same cycle. Most events are scheduled at the default
122 /// priority; these values are used to control events that need to
123 /// be ordered within a cycle.
124
125 /// Minimum priority
126 static const Priority Minimum_Pri = SCHAR_MIN;
127
128 /// If we enable tracing on a particular cycle, do that as the
129 /// very first thing so we don't miss any of the events on
130 /// that cycle (even if we enter the debugger).
131 static const Priority Debug_Enable_Pri = -101;
132
133 /// Breakpoints should happen before anything else (except
134 /// enabling trace output), so we don't miss any action when
135 /// debugging.
136 static const Priority Debug_Break_Pri = -100;
137
138 /// CPU switches schedule the new CPU's tick event for the
139 /// same cycle (after unscheduling the old CPU's tick event).
140 /// The switch needs to come before any tick events to make
141 /// sure we don't tick both CPUs in the same cycle.
142 static const Priority CPU_Switch_Pri = -31;
143
144 /// For some reason "delayed" inter-cluster writebacks are
145 /// scheduled before regular writebacks (which have default
146 /// priority). Steve?
147 static const Priority Delayed_Writeback_Pri = -1;
148
149 /// Default is zero for historical reasons.
150 static const Priority Default_Pri = 0;
151
152 /// DVFS update event leads to stats dump therefore given a lower priority
153 /// to ensure all relevant states have been updated
154 static const Priority DVFS_Update_Pri = 31;
155
156 /// Serailization needs to occur before tick events also, so
157 /// that a serialize/unserialize is identical to an on-line
158 /// CPU switch.
159 static const Priority Serialize_Pri = 32;
160
161 /// CPU ticks must come after other associated CPU events
162 /// (such as writebacks).
163 static const Priority CPU_Tick_Pri = 50;
164
165 /// Statistics events (dump, reset, etc.) come after
166 /// everything else, but before exit.
167 static const Priority Stat_Event_Pri = 90;
168
169 /// Progress events come at the end.
170 static const Priority Progress_Event_Pri = 95;
171
172 /// If we want to exit on this cycle, it's the very last thing
173 /// we do.
174 static const Priority Sim_Exit_Pri = 100;
175
176 /// Maximum priority
177 static const Priority Maximum_Pri = SCHAR_MAX;
178};
179
180/*
181 * An item on an event queue. The action caused by a given
182 * event is specified by deriving a subclass and overriding the
183 * process() member function.
184 *
185 * Caution, the order of members is chosen to maximize data packing.
186 */
187class Event : public EventBase, public Serializable
188{
189 friend class EventQueue;
190
191 private:
192 // The event queue is now a linked list of linked lists. The
193 // 'nextBin' pointer is to find the bin, where a bin is defined as
194 // when+priority. All events in the same bin will be stored in a
195 // second linked list (a stack) maintained by the 'nextInBin'
196 // pointer. The list will be accessed in LIFO order. The end
197 // result is that the insert/removal in 'nextBin' is
198 // linear/constant, and the lookup/removal in 'nextInBin' is
199 // constant/constant. Hopefully this is a significant improvement
200 // over the current fully linear insertion.
201 Event *nextBin;
202 Event *nextInBin;
203
204 static Event *insertBefore(Event *event, Event *curr);
205 static Event *removeItem(Event *event, Event *last);
206
207 Tick _when; //!< timestamp when event should be processed
208 Priority _priority; //!< event priority
209 Flags flags;
210
211#ifndef NDEBUG
212 /// Global counter to generate unique IDs for Event instances
213 static Counter instanceCounter;
214
215 /// This event's unique ID. We can also use pointer values for
216 /// this but they're not consistent across runs making debugging
217 /// more difficult. Thus we use a global counter value when
218 /// debugging.
219 Counter instance;
220
221 /// queue to which this event belongs (though it may or may not be
222 /// scheduled on this queue yet)
223 EventQueue *queue;
224#endif
225
226#ifdef EVENTQ_DEBUG
227 Tick whenCreated; //!< time created
228 Tick whenScheduled; //!< time scheduled
229#endif
230
231 void
232 setWhen(Tick when, EventQueue *q)
233 {
234 _when = when;
235#ifndef NDEBUG
236 queue = q;
237#endif
238#ifdef EVENTQ_DEBUG
239 whenScheduled = curTick();
240#endif
241 }
242
243 bool
244 initialized() const
245 {
246 return (flags & InitMask) == Initialized;
247 }
248
249 protected:
250 /// Accessor for flags.
251 Flags
252 getFlags() const
253 {
254 return flags & PublicRead;
255 }
256
257 bool
258 isFlagSet(Flags _flags) const
259 {
260 assert(_flags.noneSet(~PublicRead));
261 return flags.isSet(_flags);
262 }
263
264 /// Accessor for flags.
265 void
266 setFlags(Flags _flags)
267 {
268 assert(_flags.noneSet(~PublicWrite));
269 flags.set(_flags);
270 }
271
272 void
273 clearFlags(Flags _flags)
274 {
275 assert(_flags.noneSet(~PublicWrite));
276 flags.clear(_flags);
277 }
278
279 void
280 clearFlags()
281 {
282 flags.clear(PublicWrite);
283 }
284
285 // This function isn't really useful if TRACING_ON is not defined
286 virtual void trace(const char *action); //!< trace event activity
287
288 public:
289
290 /*
291 * Event constructor
292 * @param queue that the event gets scheduled on
293 */
294 Event(Priority p = Default_Pri, Flags f = 0)
295 : nextBin(nullptr), nextInBin(nullptr), _when(0), _priority(p),
296 flags(Initialized | f)
297 {
298 assert(f.noneSet(~PublicWrite));
299#ifndef NDEBUG
300 instance = ++instanceCounter;
301 queue = NULL;
302#endif
303#ifdef EVENTQ_DEBUG
304 whenCreated = curTick();
305 whenScheduled = 0;
306#endif
307 }
308
309 virtual ~Event();
310 virtual const std::string name() const;
311
312 /// Return a C string describing the event. This string should
313 /// *not* be dynamically allocated; just a const char array
314 /// describing the event class.
315 virtual const char *description() const;
316
317 /// Dump the current event data
318 void dump() const;
319
320 public:
321 /*
322 * This member function is invoked when the event is processed
323 * (occurs). There is no default implementation; each subclass
324 * must provide its own implementation. The event is not
325 * automatically deleted after it is processed (to allow for
326 * statically allocated event objects).
327 *
328 * If the AutoDestroy flag is set, the object is deleted once it
329 * is processed.
330 */
331 virtual void process() = 0;
332
333 /// Determine if the current event is scheduled
334 bool scheduled() const { return flags.isSet(Scheduled); }
335
336 /// Squash the current event
337 void squash() { flags.set(Squashed); }
338
339 /// Check whether the event is squashed
340 bool squashed() const { return flags.isSet(Squashed); }
341
342 /// See if this is a SimExitEvent (without resorting to RTTI)
343 bool isExitEvent() const { return flags.isSet(IsExitEvent); }
344
345 /// Check whether this event will auto-delete
346 bool isAutoDelete() const { return flags.isSet(AutoDelete); }
347
348 /// Get the time that the event is scheduled
349 Tick when() const { return _when; }
350
351 /// Get the event priority
352 Priority priority() const { return _priority; }
353
354 //! If this is part of a GlobalEvent, return the pointer to the
355 //! Global Event. By default, there is no GlobalEvent, so return
356 //! NULL. (Overridden in GlobalEvent::BarrierEvent.)
357 virtual BaseGlobalEvent *globalEvent() { return NULL; }
358
75//! Current mode of execution: parallel / serial
76extern bool inParallelMode;
77
78//! Function for returning eventq queue for the provided
79//! index. The function allocates a new queue in case one
80//! does not exist for the index, provided that the index
81//! is with in bounds.
82EventQueue *getEventQueue(uint32_t index);
83
84inline EventQueue *curEventQueue() { return _curEventQueue; }
85inline void curEventQueue(EventQueue *q) { _curEventQueue = q; }
86
87/**
88 * Common base class for Event and GlobalEvent, so they can share flag
89 * and priority definitions and accessor functions. This class should
90 * not be used directly.
91 */
92class EventBase
93{
94 protected:
95 typedef unsigned short FlagsType;
96 typedef ::Flags<FlagsType> Flags;
97
98 static const FlagsType PublicRead = 0x003f; // public readable flags
99 static const FlagsType PublicWrite = 0x001d; // public writable flags
100 static const FlagsType Squashed = 0x0001; // has been squashed
101 static const FlagsType Scheduled = 0x0002; // has been scheduled
102 static const FlagsType AutoDelete = 0x0004; // delete after dispatch
103 /**
104 * This used to be AutoSerialize. This value can't be reused
105 * without changing the checkpoint version since the flag field
106 * gets serialized.
107 */
108 static const FlagsType Reserved0 = 0x0008;
109 static const FlagsType IsExitEvent = 0x0010; // special exit event
110 static const FlagsType IsMainQueue = 0x0020; // on main event queue
111 static const FlagsType Initialized = 0x7a40; // somewhat random bits
112 static const FlagsType InitMask = 0xffc0; // mask for init bits
113
114 public:
115 typedef int8_t Priority;
116
117 /// Event priorities, to provide tie-breakers for events scheduled
118 /// at the same cycle. Most events are scheduled at the default
119 /// priority; these values are used to control events that need to
120 /// be ordered within a cycle.
121
122 /// Minimum priority
123 static const Priority Minimum_Pri = SCHAR_MIN;
124
125 /// If we enable tracing on a particular cycle, do that as the
126 /// very first thing so we don't miss any of the events on
127 /// that cycle (even if we enter the debugger).
128 static const Priority Debug_Enable_Pri = -101;
129
130 /// Breakpoints should happen before anything else (except
131 /// enabling trace output), so we don't miss any action when
132 /// debugging.
133 static const Priority Debug_Break_Pri = -100;
134
135 /// CPU switches schedule the new CPU's tick event for the
136 /// same cycle (after unscheduling the old CPU's tick event).
137 /// The switch needs to come before any tick events to make
138 /// sure we don't tick both CPUs in the same cycle.
139 static const Priority CPU_Switch_Pri = -31;
140
141 /// For some reason "delayed" inter-cluster writebacks are
142 /// scheduled before regular writebacks (which have default
143 /// priority). Steve?
144 static const Priority Delayed_Writeback_Pri = -1;
145
146 /// Default is zero for historical reasons.
147 static const Priority Default_Pri = 0;
148
149 /// DVFS update event leads to stats dump therefore given a lower priority
150 /// to ensure all relevant states have been updated
151 static const Priority DVFS_Update_Pri = 31;
152
153 /// Serailization needs to occur before tick events also, so
154 /// that a serialize/unserialize is identical to an on-line
155 /// CPU switch.
156 static const Priority Serialize_Pri = 32;
157
158 /// CPU ticks must come after other associated CPU events
159 /// (such as writebacks).
160 static const Priority CPU_Tick_Pri = 50;
161
162 /// Statistics events (dump, reset, etc.) come after
163 /// everything else, but before exit.
164 static const Priority Stat_Event_Pri = 90;
165
166 /// Progress events come at the end.
167 static const Priority Progress_Event_Pri = 95;
168
169 /// If we want to exit on this cycle, it's the very last thing
170 /// we do.
171 static const Priority Sim_Exit_Pri = 100;
172
173 /// Maximum priority
174 static const Priority Maximum_Pri = SCHAR_MAX;
175};
176
177/*
178 * An item on an event queue. The action caused by a given
179 * event is specified by deriving a subclass and overriding the
180 * process() member function.
181 *
182 * Caution, the order of members is chosen to maximize data packing.
183 */
184class Event : public EventBase, public Serializable
185{
186 friend class EventQueue;
187
188 private:
189 // The event queue is now a linked list of linked lists. The
190 // 'nextBin' pointer is to find the bin, where a bin is defined as
191 // when+priority. All events in the same bin will be stored in a
192 // second linked list (a stack) maintained by the 'nextInBin'
193 // pointer. The list will be accessed in LIFO order. The end
194 // result is that the insert/removal in 'nextBin' is
195 // linear/constant, and the lookup/removal in 'nextInBin' is
196 // constant/constant. Hopefully this is a significant improvement
197 // over the current fully linear insertion.
198 Event *nextBin;
199 Event *nextInBin;
200
201 static Event *insertBefore(Event *event, Event *curr);
202 static Event *removeItem(Event *event, Event *last);
203
204 Tick _when; //!< timestamp when event should be processed
205 Priority _priority; //!< event priority
206 Flags flags;
207
208#ifndef NDEBUG
209 /// Global counter to generate unique IDs for Event instances
210 static Counter instanceCounter;
211
212 /// This event's unique ID. We can also use pointer values for
213 /// this but they're not consistent across runs making debugging
214 /// more difficult. Thus we use a global counter value when
215 /// debugging.
216 Counter instance;
217
218 /// queue to which this event belongs (though it may or may not be
219 /// scheduled on this queue yet)
220 EventQueue *queue;
221#endif
222
223#ifdef EVENTQ_DEBUG
224 Tick whenCreated; //!< time created
225 Tick whenScheduled; //!< time scheduled
226#endif
227
228 void
229 setWhen(Tick when, EventQueue *q)
230 {
231 _when = when;
232#ifndef NDEBUG
233 queue = q;
234#endif
235#ifdef EVENTQ_DEBUG
236 whenScheduled = curTick();
237#endif
238 }
239
240 bool
241 initialized() const
242 {
243 return (flags & InitMask) == Initialized;
244 }
245
246 protected:
247 /// Accessor for flags.
248 Flags
249 getFlags() const
250 {
251 return flags & PublicRead;
252 }
253
254 bool
255 isFlagSet(Flags _flags) const
256 {
257 assert(_flags.noneSet(~PublicRead));
258 return flags.isSet(_flags);
259 }
260
261 /// Accessor for flags.
262 void
263 setFlags(Flags _flags)
264 {
265 assert(_flags.noneSet(~PublicWrite));
266 flags.set(_flags);
267 }
268
269 void
270 clearFlags(Flags _flags)
271 {
272 assert(_flags.noneSet(~PublicWrite));
273 flags.clear(_flags);
274 }
275
276 void
277 clearFlags()
278 {
279 flags.clear(PublicWrite);
280 }
281
282 // This function isn't really useful if TRACING_ON is not defined
283 virtual void trace(const char *action); //!< trace event activity
284
285 public:
286
287 /*
288 * Event constructor
289 * @param queue that the event gets scheduled on
290 */
291 Event(Priority p = Default_Pri, Flags f = 0)
292 : nextBin(nullptr), nextInBin(nullptr), _when(0), _priority(p),
293 flags(Initialized | f)
294 {
295 assert(f.noneSet(~PublicWrite));
296#ifndef NDEBUG
297 instance = ++instanceCounter;
298 queue = NULL;
299#endif
300#ifdef EVENTQ_DEBUG
301 whenCreated = curTick();
302 whenScheduled = 0;
303#endif
304 }
305
306 virtual ~Event();
307 virtual const std::string name() const;
308
309 /// Return a C string describing the event. This string should
310 /// *not* be dynamically allocated; just a const char array
311 /// describing the event class.
312 virtual const char *description() const;
313
314 /// Dump the current event data
315 void dump() const;
316
317 public:
318 /*
319 * This member function is invoked when the event is processed
320 * (occurs). There is no default implementation; each subclass
321 * must provide its own implementation. The event is not
322 * automatically deleted after it is processed (to allow for
323 * statically allocated event objects).
324 *
325 * If the AutoDestroy flag is set, the object is deleted once it
326 * is processed.
327 */
328 virtual void process() = 0;
329
330 /// Determine if the current event is scheduled
331 bool scheduled() const { return flags.isSet(Scheduled); }
332
333 /// Squash the current event
334 void squash() { flags.set(Squashed); }
335
336 /// Check whether the event is squashed
337 bool squashed() const { return flags.isSet(Squashed); }
338
339 /// See if this is a SimExitEvent (without resorting to RTTI)
340 bool isExitEvent() const { return flags.isSet(IsExitEvent); }
341
342 /// Check whether this event will auto-delete
343 bool isAutoDelete() const { return flags.isSet(AutoDelete); }
344
345 /// Get the time that the event is scheduled
346 Tick when() const { return _when; }
347
348 /// Get the event priority
349 Priority priority() const { return _priority; }
350
351 //! If this is part of a GlobalEvent, return the pointer to the
352 //! Global Event. By default, there is no GlobalEvent, so return
353 //! NULL. (Overridden in GlobalEvent::BarrierEvent.)
354 virtual BaseGlobalEvent *globalEvent() { return NULL; }
355
359#ifndef SWIG
360 void serialize(CheckpointOut &cp) const override;
361 void unserialize(CheckpointIn &cp) override;
356 void serialize(CheckpointOut &cp) const override;
357 void unserialize(CheckpointIn &cp) override;
362#endif
363};
364
358};
359
365#ifndef SWIG
366inline bool
367operator<(const Event &l, const Event &r)
368{
369 return l.when() < r.when() ||
370 (l.when() == r.when() && l.priority() < r.priority());
371}
372
373inline bool
374operator>(const Event &l, const Event &r)
375{
376 return l.when() > r.when() ||
377 (l.when() == r.when() && l.priority() > r.priority());
378}
379
380inline bool
381operator<=(const Event &l, const Event &r)
382{
383 return l.when() < r.when() ||
384 (l.when() == r.when() && l.priority() <= r.priority());
385}
386inline bool
387operator>=(const Event &l, const Event &r)
388{
389 return l.when() > r.when() ||
390 (l.when() == r.when() && l.priority() >= r.priority());
391}
392
393inline bool
394operator==(const Event &l, const Event &r)
395{
396 return l.when() == r.when() && l.priority() == r.priority();
397}
398
399inline bool
400operator!=(const Event &l, const Event &r)
401{
402 return l.when() != r.when() || l.priority() != r.priority();
403}
360inline bool
361operator<(const Event &l, const Event &r)
362{
363 return l.when() < r.when() ||
364 (l.when() == r.when() && l.priority() < r.priority());
365}
366
367inline bool
368operator>(const Event &l, const Event &r)
369{
370 return l.when() > r.when() ||
371 (l.when() == r.when() && l.priority() > r.priority());
372}
373
374inline bool
375operator<=(const Event &l, const Event &r)
376{
377 return l.when() < r.when() ||
378 (l.when() == r.when() && l.priority() <= r.priority());
379}
380inline bool
381operator>=(const Event &l, const Event &r)
382{
383 return l.when() > r.when() ||
384 (l.when() == r.when() && l.priority() >= r.priority());
385}
386
387inline bool
388operator==(const Event &l, const Event &r)
389{
390 return l.when() == r.when() && l.priority() == r.priority();
391}
392
393inline bool
394operator!=(const Event &l, const Event &r)
395{
396 return l.when() != r.when() || l.priority() != r.priority();
397}
404#endif
405
406/**
407 * Queue of events sorted in time order
408 *
409 * Events are scheduled (inserted into the event queue) using the
410 * schedule() method. This method either inserts a <i>synchronous</i>
411 * or <i>asynchronous</i> event.
412 *
413 * Synchronous events are scheduled using schedule() method with the
414 * argument 'global' set to false (default). This should only be done
415 * from a thread holding the event queue lock
416 * (EventQueue::service_mutex). The lock is always held when an event
417 * handler is called, it can therefore always insert events into its
418 * own event queue unless it voluntarily releases the lock.
419 *
420 * Events can be scheduled across thread (and event queue borders) by
421 * either scheduling asynchronous events or taking the target event
422 * queue's lock. However, the lock should <i>never</i> be taken
423 * directly since this is likely to cause deadlocks. Instead, code
424 * that needs to schedule events in other event queues should
425 * temporarily release its own queue and lock the new queue. This
426 * prevents deadlocks since a single thread never owns more than one
427 * event queue lock. This functionality is provided by the
428 * ScopedMigration helper class. Note that temporarily migrating
429 * between event queues can make the simulation non-deterministic, it
430 * should therefore be limited to cases where that can be tolerated
431 * (e.g., handling asynchronous IO or fast-forwarding in KVM).
432 *
433 * Asynchronous events can also be scheduled using the normal
434 * schedule() method with the 'global' parameter set to true. Unlike
435 * the previous queue migration strategy, this strategy is fully
436 * deterministic. This causes the event to be inserted in a separate
437 * queue of asynchronous events (async_queue), which is merged main
438 * event queue at the end of each simulation quantum (by calling the
439 * handleAsyncInsertions() method). Note that this implies that such
440 * events must happen at least one simulation quantum into the future,
441 * otherwise they risk being scheduled in the past by
442 * handleAsyncInsertions().
443 */
444class EventQueue
445{
446 private:
447 std::string objName;
448 Event *head;
449 Tick _curTick;
450
451 //! Mutex to protect async queue.
452 std::mutex async_queue_mutex;
453
454 //! List of events added by other threads to this event queue.
455 std::list<Event*> async_queue;
456
457 /**
458 * Lock protecting event handling.
459 *
460 * This lock is always taken when servicing events. It is assumed
461 * that the thread scheduling new events (not asynchronous events
462 * though) have taken this lock. This is normally done by
463 * serviceOne() since new events are typically scheduled as a
464 * response to an earlier event.
465 *
466 * This lock is intended to be used to temporarily steal an event
467 * queue to support inter-thread communication when some
468 * deterministic timing can be sacrificed for speed. For example,
469 * the KVM CPU can use this support to access devices running in a
470 * different thread.
471 *
472 * @see EventQueue::ScopedMigration.
473 * @see EventQueue::ScopedRelease
474 * @see EventQueue::lock()
475 * @see EventQueue::unlock()
476 */
477 std::mutex service_mutex;
478
479 //! Insert / remove event from the queue. Should only be called
480 //! by thread operating this queue.
481 void insert(Event *event);
482 void remove(Event *event);
483
484 //! Function for adding events to the async queue. The added events
485 //! are added to main event queue later. Threads, other than the
486 //! owning thread, should call this function instead of insert().
487 void asyncInsert(Event *event);
488
489 EventQueue(const EventQueue &);
490
491 public:
398
399/**
400 * Queue of events sorted in time order
401 *
402 * Events are scheduled (inserted into the event queue) using the
403 * schedule() method. This method either inserts a <i>synchronous</i>
404 * or <i>asynchronous</i> event.
405 *
406 * Synchronous events are scheduled using schedule() method with the
407 * argument 'global' set to false (default). This should only be done
408 * from a thread holding the event queue lock
409 * (EventQueue::service_mutex). The lock is always held when an event
410 * handler is called, it can therefore always insert events into its
411 * own event queue unless it voluntarily releases the lock.
412 *
413 * Events can be scheduled across thread (and event queue borders) by
414 * either scheduling asynchronous events or taking the target event
415 * queue's lock. However, the lock should <i>never</i> be taken
416 * directly since this is likely to cause deadlocks. Instead, code
417 * that needs to schedule events in other event queues should
418 * temporarily release its own queue and lock the new queue. This
419 * prevents deadlocks since a single thread never owns more than one
420 * event queue lock. This functionality is provided by the
421 * ScopedMigration helper class. Note that temporarily migrating
422 * between event queues can make the simulation non-deterministic, it
423 * should therefore be limited to cases where that can be tolerated
424 * (e.g., handling asynchronous IO or fast-forwarding in KVM).
425 *
426 * Asynchronous events can also be scheduled using the normal
427 * schedule() method with the 'global' parameter set to true. Unlike
428 * the previous queue migration strategy, this strategy is fully
429 * deterministic. This causes the event to be inserted in a separate
430 * queue of asynchronous events (async_queue), which is merged main
431 * event queue at the end of each simulation quantum (by calling the
432 * handleAsyncInsertions() method). Note that this implies that such
433 * events must happen at least one simulation quantum into the future,
434 * otherwise they risk being scheduled in the past by
435 * handleAsyncInsertions().
436 */
437class EventQueue
438{
439 private:
440 std::string objName;
441 Event *head;
442 Tick _curTick;
443
444 //! Mutex to protect async queue.
445 std::mutex async_queue_mutex;
446
447 //! List of events added by other threads to this event queue.
448 std::list<Event*> async_queue;
449
450 /**
451 * Lock protecting event handling.
452 *
453 * This lock is always taken when servicing events. It is assumed
454 * that the thread scheduling new events (not asynchronous events
455 * though) have taken this lock. This is normally done by
456 * serviceOne() since new events are typically scheduled as a
457 * response to an earlier event.
458 *
459 * This lock is intended to be used to temporarily steal an event
460 * queue to support inter-thread communication when some
461 * deterministic timing can be sacrificed for speed. For example,
462 * the KVM CPU can use this support to access devices running in a
463 * different thread.
464 *
465 * @see EventQueue::ScopedMigration.
466 * @see EventQueue::ScopedRelease
467 * @see EventQueue::lock()
468 * @see EventQueue::unlock()
469 */
470 std::mutex service_mutex;
471
472 //! Insert / remove event from the queue. Should only be called
473 //! by thread operating this queue.
474 void insert(Event *event);
475 void remove(Event *event);
476
477 //! Function for adding events to the async queue. The added events
478 //! are added to main event queue later. Threads, other than the
479 //! owning thread, should call this function instead of insert().
480 void asyncInsert(Event *event);
481
482 EventQueue(const EventQueue &);
483
484 public:
492#ifndef SWIG
493 /**
494 * Temporarily migrate execution to a different event queue.
495 *
496 * An instance of this class temporarily migrates execution to a
497 * different event queue by releasing the current queue, locking
498 * the new queue, and updating curEventQueue(). This can, for
499 * example, be useful when performing IO across thread event
500 * queues when timing is not crucial (e.g., during fast
501 * forwarding).
502 */
503 class ScopedMigration
504 {
505 public:
506 ScopedMigration(EventQueue *_new_eq)
507 : new_eq(*_new_eq), old_eq(*curEventQueue())
508 {
509 old_eq.unlock();
510 new_eq.lock();
511 curEventQueue(&new_eq);
512 }
513
514 ~ScopedMigration()
515 {
516 new_eq.unlock();
517 old_eq.lock();
518 curEventQueue(&old_eq);
519 }
520
521 private:
522 EventQueue &new_eq;
523 EventQueue &old_eq;
524 };
525
526 /**
527 * Temporarily release the event queue service lock.
528 *
529 * There are cases where it is desirable to temporarily release
530 * the event queue lock to prevent deadlocks. For example, when
531 * waiting on the global barrier, we need to release the lock to
532 * prevent deadlocks from happening when another thread tries to
533 * temporarily take over the event queue waiting on the barrier.
534 */
535 class ScopedRelease
536 {
537 public:
538 ScopedRelease(EventQueue *_eq)
539 : eq(*_eq)
540 {
541 eq.unlock();
542 }
543
544 ~ScopedRelease()
545 {
546 eq.lock();
547 }
548
549 private:
550 EventQueue &eq;
551 };
485 /**
486 * Temporarily migrate execution to a different event queue.
487 *
488 * An instance of this class temporarily migrates execution to a
489 * different event queue by releasing the current queue, locking
490 * the new queue, and updating curEventQueue(). This can, for
491 * example, be useful when performing IO across thread event
492 * queues when timing is not crucial (e.g., during fast
493 * forwarding).
494 */
495 class ScopedMigration
496 {
497 public:
498 ScopedMigration(EventQueue *_new_eq)
499 : new_eq(*_new_eq), old_eq(*curEventQueue())
500 {
501 old_eq.unlock();
502 new_eq.lock();
503 curEventQueue(&new_eq);
504 }
505
506 ~ScopedMigration()
507 {
508 new_eq.unlock();
509 old_eq.lock();
510 curEventQueue(&old_eq);
511 }
512
513 private:
514 EventQueue &new_eq;
515 EventQueue &old_eq;
516 };
517
518 /**
519 * Temporarily release the event queue service lock.
520 *
521 * There are cases where it is desirable to temporarily release
522 * the event queue lock to prevent deadlocks. For example, when
523 * waiting on the global barrier, we need to release the lock to
524 * prevent deadlocks from happening when another thread tries to
525 * temporarily take over the event queue waiting on the barrier.
526 */
527 class ScopedRelease
528 {
529 public:
530 ScopedRelease(EventQueue *_eq)
531 : eq(*_eq)
532 {
533 eq.unlock();
534 }
535
536 ~ScopedRelease()
537 {
538 eq.lock();
539 }
540
541 private:
542 EventQueue &eq;
543 };
552#endif
553
554 EventQueue(const std::string &n);
555
556 virtual const std::string name() const { return objName; }
557 void name(const std::string &st) { objName = st; }
558
559 //! Schedule the given event on this queue. Safe to call from any
560 //! thread.
561 void schedule(Event *event, Tick when, bool global = false);
562
563 //! Deschedule the specified event. Should be called only from the
564 //! owning thread.
565 void deschedule(Event *event);
566
567 //! Reschedule the specified event. Should be called only from
568 //! the owning thread.
569 void reschedule(Event *event, Tick when, bool always = false);
570
571 Tick nextTick() const { return head->when(); }
572 void setCurTick(Tick newVal) { _curTick = newVal; }
573 Tick getCurTick() const { return _curTick; }
574 Event *getHead() const { return head; }
575
576 Event *serviceOne();
577
578 // process all events up to the given timestamp. we inline a
579 // quick test to see if there are any events to process; if so,
580 // call the internal out-of-line version to process them all.
581 void
582 serviceEvents(Tick when)
583 {
584 while (!empty()) {
585 if (nextTick() > when)
586 break;
587
588 /**
589 * @todo this assert is a good bug catcher. I need to
590 * make it true again.
591 */
592 //assert(head->when() >= when && "event scheduled in the past");
593 serviceOne();
594 }
595
596 setCurTick(when);
597 }
598
599 // return true if no events are queued
600 bool empty() const { return head == NULL; }
601
602 void dump() const;
603
604 bool debugVerify() const;
605
606 //! Function for moving events from the async_queue to the main queue.
607 void handleAsyncInsertions();
608
609 /**
610 * Function to signal that the event loop should be woken up because
611 * an event has been scheduled by an agent outside the gem5 event
612 * loop(s) whose event insertion may not have been noticed by gem5.
613 * This function isn't needed by the usual gem5 event loop but may
614 * be necessary in derived EventQueues which host gem5 onto other
615 * schedulers.
616 *
617 * @param when Time of a delayed wakeup (if known). This parameter
618 * can be used by an implementation to schedule a wakeup in the
619 * future if it is sure it will remain active until then.
620 * Or it can be ignored and the event queue can be woken up now.
621 */
622 virtual void wakeup(Tick when = (Tick)-1) { }
623
624 /**
625 * function for replacing the head of the event queue, so that a
626 * different set of events can run without disturbing events that have
627 * already been scheduled. Already scheduled events can be processed
628 * by replacing the original head back.
629 * USING THIS FUNCTION CAN BE DANGEROUS TO THE HEALTH OF THE SIMULATOR.
630 * NOT RECOMMENDED FOR USE.
631 */
632 Event* replaceHead(Event* s);
633
634 /**@{*/
635 /**
636 * Provide an interface for locking/unlocking the event queue.
637 *
638 * @warn Do NOT use these methods directly unless you really know
639 * what you are doing. Incorrect use can easily lead to simulator
640 * deadlocks.
641 *
642 * @see EventQueue::ScopedMigration.
643 * @see EventQueue::ScopedRelease
644 * @see EventQueue
645 */
646 void lock() { service_mutex.lock(); }
647 void unlock() { service_mutex.unlock(); }
648 /**@}*/
649
650 /**
651 * Reschedule an event after a checkpoint.
652 *
653 * Since events don't know which event queue they belong to,
654 * parent objects need to reschedule events themselves. This
655 * method conditionally schedules an event that has the Scheduled
656 * flag set. It should be called by parent objects after
657 * unserializing an object.
658 *
659 * @warn Only use this method after unserializing an Event.
660 */
661 void checkpointReschedule(Event *event);
662
663 virtual ~EventQueue() { }
664};
665
666void dumpMainQueue();
667
544
545 EventQueue(const std::string &n);
546
547 virtual const std::string name() const { return objName; }
548 void name(const std::string &st) { objName = st; }
549
550 //! Schedule the given event on this queue. Safe to call from any
551 //! thread.
552 void schedule(Event *event, Tick when, bool global = false);
553
554 //! Deschedule the specified event. Should be called only from the
555 //! owning thread.
556 void deschedule(Event *event);
557
558 //! Reschedule the specified event. Should be called only from
559 //! the owning thread.
560 void reschedule(Event *event, Tick when, bool always = false);
561
562 Tick nextTick() const { return head->when(); }
563 void setCurTick(Tick newVal) { _curTick = newVal; }
564 Tick getCurTick() const { return _curTick; }
565 Event *getHead() const { return head; }
566
567 Event *serviceOne();
568
569 // process all events up to the given timestamp. we inline a
570 // quick test to see if there are any events to process; if so,
571 // call the internal out-of-line version to process them all.
572 void
573 serviceEvents(Tick when)
574 {
575 while (!empty()) {
576 if (nextTick() > when)
577 break;
578
579 /**
580 * @todo this assert is a good bug catcher. I need to
581 * make it true again.
582 */
583 //assert(head->when() >= when && "event scheduled in the past");
584 serviceOne();
585 }
586
587 setCurTick(when);
588 }
589
590 // return true if no events are queued
591 bool empty() const { return head == NULL; }
592
593 void dump() const;
594
595 bool debugVerify() const;
596
597 //! Function for moving events from the async_queue to the main queue.
598 void handleAsyncInsertions();
599
600 /**
601 * Function to signal that the event loop should be woken up because
602 * an event has been scheduled by an agent outside the gem5 event
603 * loop(s) whose event insertion may not have been noticed by gem5.
604 * This function isn't needed by the usual gem5 event loop but may
605 * be necessary in derived EventQueues which host gem5 onto other
606 * schedulers.
607 *
608 * @param when Time of a delayed wakeup (if known). This parameter
609 * can be used by an implementation to schedule a wakeup in the
610 * future if it is sure it will remain active until then.
611 * Or it can be ignored and the event queue can be woken up now.
612 */
613 virtual void wakeup(Tick when = (Tick)-1) { }
614
615 /**
616 * function for replacing the head of the event queue, so that a
617 * different set of events can run without disturbing events that have
618 * already been scheduled. Already scheduled events can be processed
619 * by replacing the original head back.
620 * USING THIS FUNCTION CAN BE DANGEROUS TO THE HEALTH OF THE SIMULATOR.
621 * NOT RECOMMENDED FOR USE.
622 */
623 Event* replaceHead(Event* s);
624
625 /**@{*/
626 /**
627 * Provide an interface for locking/unlocking the event queue.
628 *
629 * @warn Do NOT use these methods directly unless you really know
630 * what you are doing. Incorrect use can easily lead to simulator
631 * deadlocks.
632 *
633 * @see EventQueue::ScopedMigration.
634 * @see EventQueue::ScopedRelease
635 * @see EventQueue
636 */
637 void lock() { service_mutex.lock(); }
638 void unlock() { service_mutex.unlock(); }
639 /**@}*/
640
641 /**
642 * Reschedule an event after a checkpoint.
643 *
644 * Since events don't know which event queue they belong to,
645 * parent objects need to reschedule events themselves. This
646 * method conditionally schedules an event that has the Scheduled
647 * flag set. It should be called by parent objects after
648 * unserializing an object.
649 *
650 * @warn Only use this method after unserializing an Event.
651 */
652 void checkpointReschedule(Event *event);
653
654 virtual ~EventQueue() { }
655};
656
657void dumpMainQueue();
658
668#ifndef SWIG
669class EventManager
670{
671 protected:
672 /** A pointer to this object's event queue */
673 EventQueue *eventq;
674
675 public:
676 EventManager(EventManager &em) : eventq(em.eventq) {}
677 EventManager(EventManager *em) : eventq(em->eventq) {}
678 EventManager(EventQueue *eq) : eventq(eq) {}
679
680 EventQueue *
681 eventQueue() const
682 {
683 return eventq;
684 }
685
686 void
687 schedule(Event &event, Tick when)
688 {
689 eventq->schedule(&event, when);
690 }
691
692 void
693 deschedule(Event &event)
694 {
695 eventq->deschedule(&event);
696 }
697
698 void
699 reschedule(Event &event, Tick when, bool always = false)
700 {
701 eventq->reschedule(&event, when, always);
702 }
703
704 void
705 schedule(Event *event, Tick when)
706 {
707 eventq->schedule(event, when);
708 }
709
710 void
711 deschedule(Event *event)
712 {
713 eventq->deschedule(event);
714 }
715
716 void
717 reschedule(Event *event, Tick when, bool always = false)
718 {
719 eventq->reschedule(event, when, always);
720 }
721
722 void wakeupEventQueue(Tick when = (Tick)-1)
723 {
724 eventq->wakeup(when);
725 }
726
727 void setCurTick(Tick newVal) { eventq->setCurTick(newVal); }
728};
729
730template <class T, void (T::* F)()>
731void
732DelayFunction(EventQueue *eventq, Tick when, T *object)
733{
734 class DelayEvent : public Event
735 {
736 private:
737 T *object;
738
739 public:
740 DelayEvent(T *o)
741 : Event(Default_Pri, AutoDelete), object(o)
742 { }
743 void process() { (object->*F)(); }
744 const char *description() const { return "delay"; }
745 };
746
747 eventq->schedule(new DelayEvent(object), when);
748}
749
750template <class T, void (T::* F)()>
751class EventWrapper : public Event
752{
753 private:
754 T *object;
755
756 public:
757 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
758 : Event(p), object(obj)
759 {
760 if (del)
761 setFlags(AutoDelete);
762 }
763
764 EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
765 : Event(p), object(&obj)
766 {
767 if (del)
768 setFlags(AutoDelete);
769 }
770
771 void process() { (object->*F)(); }
772
773 const std::string
774 name() const
775 {
776 return object->name() + ".wrapped_event";
777 }
778
779 const char *description() const { return "EventWrapped"; }
780};
659class EventManager
660{
661 protected:
662 /** A pointer to this object's event queue */
663 EventQueue *eventq;
664
665 public:
666 EventManager(EventManager &em) : eventq(em.eventq) {}
667 EventManager(EventManager *em) : eventq(em->eventq) {}
668 EventManager(EventQueue *eq) : eventq(eq) {}
669
670 EventQueue *
671 eventQueue() const
672 {
673 return eventq;
674 }
675
676 void
677 schedule(Event &event, Tick when)
678 {
679 eventq->schedule(&event, when);
680 }
681
682 void
683 deschedule(Event &event)
684 {
685 eventq->deschedule(&event);
686 }
687
688 void
689 reschedule(Event &event, Tick when, bool always = false)
690 {
691 eventq->reschedule(&event, when, always);
692 }
693
694 void
695 schedule(Event *event, Tick when)
696 {
697 eventq->schedule(event, when);
698 }
699
700 void
701 deschedule(Event *event)
702 {
703 eventq->deschedule(event);
704 }
705
706 void
707 reschedule(Event *event, Tick when, bool always = false)
708 {
709 eventq->reschedule(event, when, always);
710 }
711
712 void wakeupEventQueue(Tick when = (Tick)-1)
713 {
714 eventq->wakeup(when);
715 }
716
717 void setCurTick(Tick newVal) { eventq->setCurTick(newVal); }
718};
719
720template <class T, void (T::* F)()>
721void
722DelayFunction(EventQueue *eventq, Tick when, T *object)
723{
724 class DelayEvent : public Event
725 {
726 private:
727 T *object;
728
729 public:
730 DelayEvent(T *o)
731 : Event(Default_Pri, AutoDelete), object(o)
732 { }
733 void process() { (object->*F)(); }
734 const char *description() const { return "delay"; }
735 };
736
737 eventq->schedule(new DelayEvent(object), when);
738}
739
740template <class T, void (T::* F)()>
741class EventWrapper : public Event
742{
743 private:
744 T *object;
745
746 public:
747 EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
748 : Event(p), object(obj)
749 {
750 if (del)
751 setFlags(AutoDelete);
752 }
753
754 EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
755 : Event(p), object(&obj)
756 {
757 if (del)
758 setFlags(AutoDelete);
759 }
760
761 void process() { (object->*F)(); }
762
763 const std::string
764 name() const
765 {
766 return object->name() + ".wrapped_event";
767 }
768
769 const char *description() const { return "EventWrapped"; }
770};
781#endif
782
783#endif // __SIM_EVENTQ_HH__
771
772#endif // __SIM_EVENTQ_HH__