scheduler.cc (13095:836fd7929940) scheduler.cc (13096:9295fa397b3f)
1/*
2 * Copyright 2018 Google, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met: redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer;
8 * redistributions in binary form must reproduce the above copyright
9 * notice, this list of conditions and the following disclaimer in the
10 * documentation and/or other materials provided with the distribution;
11 * neither the name of the copyright holders nor the names of its
12 * contributors may be used to endorse or promote products derived from
13 * this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 * Authors: Gabe Black
28 */
29
30#include "systemc/core/scheduler.hh"
31
32#include "base/fiber.hh"
33#include "base/logging.hh"
34#include "sim/eventq.hh"
35#include "systemc/core/kernel.hh"
36#include "systemc/ext/core/sc_main.hh"
37
38namespace sc_gem5
39{
40
41Scheduler::Scheduler() :
42 eq(nullptr), readyEvent(this, false, ReadyPriority),
43 pauseEvent(this, false, PausePriority),
44 stopEvent(this, false, StopPriority),
45 scMain(nullptr),
46 starvationEvent(this, false, StarvationPriority),
47 _started(false), _paused(false), _stopped(false),
48 maxTickEvent(this, false, MaxTickPriority),
49 _numCycles(0), _current(nullptr), initDone(false),
50 runOnce(false)
51{}
52
53Scheduler::~Scheduler()
54{
55 // Clear out everything that belongs to us to make sure nobody tries to
56 // clear themselves out after the scheduler goes away.
57 clear();
58}
59
60void
61Scheduler::clear()
62{
63 // Delta notifications.
64 for (auto &e: deltas)
65 e->deschedule();
66 deltas.clear();
67
68 // Timed notifications.
69 for (auto &tsp: timeSlots) {
70 TimeSlot *&ts = tsp.second;
71 for (auto &e: ts->events)
72 e->deschedule();
73 deschedule(ts);
74 }
75 timeSlots.clear();
76
77 // gem5 events.
78 if (readyEvent.scheduled())
79 deschedule(&readyEvent);
80 if (pauseEvent.scheduled())
81 deschedule(&pauseEvent);
82 if (stopEvent.scheduled())
83 deschedule(&stopEvent);
84 if (starvationEvent.scheduled())
85 deschedule(&starvationEvent);
86 if (maxTickEvent.scheduled())
87 deschedule(&maxTickEvent);
88
89 Process *p;
90 while ((p = toFinalize.getNext()))
91 p->popListNode();
92 while ((p = initList.getNext()))
93 p->popListNode();
94 while ((p = readyList.getNext()))
95 p->popListNode();
96
97 Channel *c;
98 while ((c = updateList.getNext()))
99 c->popListNode();
100}
101
102void
103Scheduler::initPhase()
104{
105 for (Process *p = toFinalize.getNext(); p; p = toFinalize.getNext()) {
106 p->finalize();
107 p->popListNode();
108 }
109
110 for (Process *p = initList.getNext(); p; p = initList.getNext()) {
111 p->finalize();
112 p->popListNode();
113 p->ready();
114 }
115
116 update();
117
118 for (auto &e: deltas)
119 e->run();
120 deltas.clear();
121
122 for (auto ets: eventsToSchedule)
123 eq->schedule(ets.first, ets.second);
124 eventsToSchedule.clear();
125
126 if (_started) {
1/*
2 * Copyright 2018 Google, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met: redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer;
8 * redistributions in binary form must reproduce the above copyright
9 * notice, this list of conditions and the following disclaimer in the
10 * documentation and/or other materials provided with the distribution;
11 * neither the name of the copyright holders nor the names of its
12 * contributors may be used to endorse or promote products derived from
13 * this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 * Authors: Gabe Black
28 */
29
30#include "systemc/core/scheduler.hh"
31
32#include "base/fiber.hh"
33#include "base/logging.hh"
34#include "sim/eventq.hh"
35#include "systemc/core/kernel.hh"
36#include "systemc/ext/core/sc_main.hh"
37
38namespace sc_gem5
39{
40
41Scheduler::Scheduler() :
42 eq(nullptr), readyEvent(this, false, ReadyPriority),
43 pauseEvent(this, false, PausePriority),
44 stopEvent(this, false, StopPriority),
45 scMain(nullptr),
46 starvationEvent(this, false, StarvationPriority),
47 _started(false), _paused(false), _stopped(false),
48 maxTickEvent(this, false, MaxTickPriority),
49 _numCycles(0), _current(nullptr), initDone(false),
50 runOnce(false)
51{}
52
53Scheduler::~Scheduler()
54{
55 // Clear out everything that belongs to us to make sure nobody tries to
56 // clear themselves out after the scheduler goes away.
57 clear();
58}
59
60void
61Scheduler::clear()
62{
63 // Delta notifications.
64 for (auto &e: deltas)
65 e->deschedule();
66 deltas.clear();
67
68 // Timed notifications.
69 for (auto &tsp: timeSlots) {
70 TimeSlot *&ts = tsp.second;
71 for (auto &e: ts->events)
72 e->deschedule();
73 deschedule(ts);
74 }
75 timeSlots.clear();
76
77 // gem5 events.
78 if (readyEvent.scheduled())
79 deschedule(&readyEvent);
80 if (pauseEvent.scheduled())
81 deschedule(&pauseEvent);
82 if (stopEvent.scheduled())
83 deschedule(&stopEvent);
84 if (starvationEvent.scheduled())
85 deschedule(&starvationEvent);
86 if (maxTickEvent.scheduled())
87 deschedule(&maxTickEvent);
88
89 Process *p;
90 while ((p = toFinalize.getNext()))
91 p->popListNode();
92 while ((p = initList.getNext()))
93 p->popListNode();
94 while ((p = readyList.getNext()))
95 p->popListNode();
96
97 Channel *c;
98 while ((c = updateList.getNext()))
99 c->popListNode();
100}
101
102void
103Scheduler::initPhase()
104{
105 for (Process *p = toFinalize.getNext(); p; p = toFinalize.getNext()) {
106 p->finalize();
107 p->popListNode();
108 }
109
110 for (Process *p = initList.getNext(); p; p = initList.getNext()) {
111 p->finalize();
112 p->popListNode();
113 p->ready();
114 }
115
116 update();
117
118 for (auto &e: deltas)
119 e->run();
120 deltas.clear();
121
122 for (auto ets: eventsToSchedule)
123 eq->schedule(ets.first, ets.second);
124 eventsToSchedule.clear();
125
126 if (_started) {
127 if (starved() && !runToTime)
127 if (!runToTime && starved())
128 scheduleStarvationEvent();
129 kernel->status(::sc_core::SC_RUNNING);
130 }
131
132 initDone = true;
133}
134
135void
136Scheduler::reg(Process *p)
137{
138 if (initDone) {
139 // If we're past initialization, finalize static sensitivity.
140 p->finalize();
141 // Mark the process as ready.
142 p->ready();
143 } else {
144 // Otherwise, record that this process should be initialized once we
145 // get there.
146 initList.pushLast(p);
147 }
148}
149
150void
151Scheduler::dontInitialize(Process *p)
152{
153 if (initDone) {
154 // Pop this process off of the ready list.
155 p->popListNode();
156 } else {
157 // Push this process onto the list of processes which still need
158 // their static sensitivity to be finalized. That implicitly pops it
159 // off the list of processes to be initialized/marked ready.
160 toFinalize.pushLast(p);
161 }
162}
163
164void
165Scheduler::yield()
166{
167 _current = readyList.getNext();
168 if (!_current) {
169 // There are no more processes, so return control to evaluate.
170 Fiber::primaryFiber()->run();
171 } else {
172 _current->popListNode();
173 // Switch to whatever Fiber is supposed to run this process. All
174 // Fibers which aren't running should be parked at this line.
175 _current->fiber()->run();
176 // If the current process needs to be manually started, start it.
177 if (_current && _current->needsStart()) {
178 _current->needsStart(false);
179 _current->run();
180 }
181 }
182 if (_current && _current->excWrapper) {
183 // Make sure this isn't a method process.
184 assert(!_current->needsStart());
185 auto ew = _current->excWrapper;
186 _current->excWrapper = nullptr;
187 ew->throw_it();
188 }
189}
190
191void
192Scheduler::ready(Process *p)
193{
194 // Clump methods together to minimize context switching.
195 if (p->procKind() == ::sc_core::SC_METHOD_PROC_)
196 readyList.pushFirst(p);
197 else
198 readyList.pushLast(p);
199
200 scheduleReadyEvent();
201}
202
203void
204Scheduler::requestUpdate(Channel *c)
205{
206 updateList.pushLast(c);
207 scheduleReadyEvent();
208}
209
210void
211Scheduler::scheduleReadyEvent()
212{
213 // Schedule the evaluate and update phases.
214 if (!readyEvent.scheduled()) {
215 schedule(&readyEvent);
216 if (starvationEvent.scheduled())
217 deschedule(&starvationEvent);
218 }
219}
220
221void
222Scheduler::scheduleStarvationEvent()
223{
224 if (!starvationEvent.scheduled()) {
225 schedule(&starvationEvent);
226 if (readyEvent.scheduled())
227 deschedule(&readyEvent);
228 }
229}
230
231void
232Scheduler::runReady()
233{
234 bool empty = readyList.empty();
235
236 // The evaluation phase.
237 do {
238 yield();
239 } while (!readyList.empty());
240
241 if (!empty)
242 _numCycles++;
243
244 // The update phase.
245 update();
246
128 scheduleStarvationEvent();
129 kernel->status(::sc_core::SC_RUNNING);
130 }
131
132 initDone = true;
133}
134
135void
136Scheduler::reg(Process *p)
137{
138 if (initDone) {
139 // If we're past initialization, finalize static sensitivity.
140 p->finalize();
141 // Mark the process as ready.
142 p->ready();
143 } else {
144 // Otherwise, record that this process should be initialized once we
145 // get there.
146 initList.pushLast(p);
147 }
148}
149
150void
151Scheduler::dontInitialize(Process *p)
152{
153 if (initDone) {
154 // Pop this process off of the ready list.
155 p->popListNode();
156 } else {
157 // Push this process onto the list of processes which still need
158 // their static sensitivity to be finalized. That implicitly pops it
159 // off the list of processes to be initialized/marked ready.
160 toFinalize.pushLast(p);
161 }
162}
163
164void
165Scheduler::yield()
166{
167 _current = readyList.getNext();
168 if (!_current) {
169 // There are no more processes, so return control to evaluate.
170 Fiber::primaryFiber()->run();
171 } else {
172 _current->popListNode();
173 // Switch to whatever Fiber is supposed to run this process. All
174 // Fibers which aren't running should be parked at this line.
175 _current->fiber()->run();
176 // If the current process needs to be manually started, start it.
177 if (_current && _current->needsStart()) {
178 _current->needsStart(false);
179 _current->run();
180 }
181 }
182 if (_current && _current->excWrapper) {
183 // Make sure this isn't a method process.
184 assert(!_current->needsStart());
185 auto ew = _current->excWrapper;
186 _current->excWrapper = nullptr;
187 ew->throw_it();
188 }
189}
190
191void
192Scheduler::ready(Process *p)
193{
194 // Clump methods together to minimize context switching.
195 if (p->procKind() == ::sc_core::SC_METHOD_PROC_)
196 readyList.pushFirst(p);
197 else
198 readyList.pushLast(p);
199
200 scheduleReadyEvent();
201}
202
203void
204Scheduler::requestUpdate(Channel *c)
205{
206 updateList.pushLast(c);
207 scheduleReadyEvent();
208}
209
210void
211Scheduler::scheduleReadyEvent()
212{
213 // Schedule the evaluate and update phases.
214 if (!readyEvent.scheduled()) {
215 schedule(&readyEvent);
216 if (starvationEvent.scheduled())
217 deschedule(&starvationEvent);
218 }
219}
220
221void
222Scheduler::scheduleStarvationEvent()
223{
224 if (!starvationEvent.scheduled()) {
225 schedule(&starvationEvent);
226 if (readyEvent.scheduled())
227 deschedule(&readyEvent);
228 }
229}
230
231void
232Scheduler::runReady()
233{
234 bool empty = readyList.empty();
235
236 // The evaluation phase.
237 do {
238 yield();
239 } while (!readyList.empty());
240
241 if (!empty)
242 _numCycles++;
243
244 // The update phase.
245 update();
246
247 if (starved() && !runToTime)
248 scheduleStarvationEvent();
249
250 // The delta phase.
251 for (auto &e: deltas)
252 e->run();
253 deltas.clear();
254
247 // The delta phase.
248 for (auto &e: deltas)
249 e->run();
250 deltas.clear();
251
252 if (!runToTime && starved())
253 scheduleStarvationEvent();
254
255 if (runOnce)
256 schedulePause();
257}
258
259void
260Scheduler::update()
261{
262 Channel *channel = updateList.getNext();
263 while (channel) {
264 channel->popListNode();
265 channel->update();
266 channel = updateList.getNext();
267 }
268}
269
270void
271Scheduler::pause()
272{
273 _paused = true;
274 kernel->status(::sc_core::SC_PAUSED);
275 runOnce = false;
276 scMain->run();
277}
278
279void
280Scheduler::stop()
281{
282 _stopped = true;
283 kernel->stop();
284
285 clear();
286
287 runOnce = false;
288 scMain->run();
289}
290
291void
292Scheduler::start(Tick max_tick, bool run_to_time)
293{
294 // We should be running from sc_main. Keep track of that Fiber to return
295 // to later.
296 scMain = Fiber::currentFiber();
297
298 _started = true;
299 _paused = false;
300 _stopped = false;
301 runToTime = run_to_time;
302
303 maxTick = max_tick;
304
305 if (initDone) {
255 if (runOnce)
256 schedulePause();
257}
258
259void
260Scheduler::update()
261{
262 Channel *channel = updateList.getNext();
263 while (channel) {
264 channel->popListNode();
265 channel->update();
266 channel = updateList.getNext();
267 }
268}
269
270void
271Scheduler::pause()
272{
273 _paused = true;
274 kernel->status(::sc_core::SC_PAUSED);
275 runOnce = false;
276 scMain->run();
277}
278
279void
280Scheduler::stop()
281{
282 _stopped = true;
283 kernel->stop();
284
285 clear();
286
287 runOnce = false;
288 scMain->run();
289}
290
291void
292Scheduler::start(Tick max_tick, bool run_to_time)
293{
294 // We should be running from sc_main. Keep track of that Fiber to return
295 // to later.
296 scMain = Fiber::currentFiber();
297
298 _started = true;
299 _paused = false;
300 _stopped = false;
301 runToTime = run_to_time;
302
303 maxTick = max_tick;
304
305 if (initDone) {
306 if (starved() && !runToTime)
306 if (!runToTime && starved())
307 scheduleStarvationEvent();
308 kernel->status(::sc_core::SC_RUNNING);
309 }
310
311 schedule(&maxTickEvent, maxTick);
312
313 // Return to gem5 to let it run events, etc.
314 Fiber::primaryFiber()->run();
315
316 if (pauseEvent.scheduled())
317 deschedule(&pauseEvent);
318 if (stopEvent.scheduled())
319 deschedule(&stopEvent);
320 if (maxTickEvent.scheduled())
321 deschedule(&maxTickEvent);
322 if (starvationEvent.scheduled())
323 deschedule(&starvationEvent);
324}
325
326void
327Scheduler::oneCycle()
328{
329 runOnce = true;
330 scheduleReadyEvent();
331 start(::MaxTick, false);
332}
333
334void
335Scheduler::schedulePause()
336{
337 if (pauseEvent.scheduled())
338 return;
339
340 schedule(&pauseEvent);
341}
342
343void
344Scheduler::scheduleStop(bool finish_delta)
345{
346 if (stopEvent.scheduled())
347 return;
348
349 if (!finish_delta) {
350 // If we're not supposed to finish the delta cycle, flush all
351 // pending activity.
352 clear();
353 }
354 schedule(&stopEvent);
355}
356
357Scheduler scheduler;
358
359} // namespace sc_gem5
307 scheduleStarvationEvent();
308 kernel->status(::sc_core::SC_RUNNING);
309 }
310
311 schedule(&maxTickEvent, maxTick);
312
313 // Return to gem5 to let it run events, etc.
314 Fiber::primaryFiber()->run();
315
316 if (pauseEvent.scheduled())
317 deschedule(&pauseEvent);
318 if (stopEvent.scheduled())
319 deschedule(&stopEvent);
320 if (maxTickEvent.scheduled())
321 deschedule(&maxTickEvent);
322 if (starvationEvent.scheduled())
323 deschedule(&starvationEvent);
324}
325
326void
327Scheduler::oneCycle()
328{
329 runOnce = true;
330 scheduleReadyEvent();
331 start(::MaxTick, false);
332}
333
334void
335Scheduler::schedulePause()
336{
337 if (pauseEvent.scheduled())
338 return;
339
340 schedule(&pauseEvent);
341}
342
343void
344Scheduler::scheduleStop(bool finish_delta)
345{
346 if (stopEvent.scheduled())
347 return;
348
349 if (!finish_delta) {
350 // If we're not supposed to finish the delta cycle, flush all
351 // pending activity.
352 clear();
353 }
354 schedule(&stopEvent);
355}
356
357Scheduler scheduler;
358
359} // namespace sc_gem5