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), initReady(false),
50 runOnce(false)
51{}
52
53void
54Scheduler::prepareForInit()
55{
56 for (Process *p = toFinalize.getNext(); p; p = toFinalize.getNext()) {
57 p->finalize();
58 p->popListNode();
59 }
60
61 for (Process *p = initList.getNext(); p; p = initList.getNext()) {
62 p->finalize();
63 p->popListNode();
64 p->ready();
65 }
66
67 for (auto ets: eventsToSchedule)
68 eq->schedule(ets.first, ets.second);
69 eventsToSchedule.clear();
70
71 if (_started)
72 eq->schedule(&maxTickEvent, maxTick);
73
74 initReady = true;
75}
76
77void
78Scheduler::reg(Process *p)
79{
80 if (initReady) {
81 // If we're past initialization, finalize static sensitivity.
82 p->finalize();
83 // Mark the process as ready.
84 p->ready();
85 } else {
86 // Otherwise, record that this process should be initialized once we
87 // get there.
88 initList.pushLast(p);
89 }
90}
91
92void
93Scheduler::dontInitialize(Process *p)
94{
95 if (initReady) {
96 // Pop this process off of the ready list.
97 p->popListNode();
98 } else {
99 // Push this process onto the list of processes which still need
100 // their static sensitivity to be finalized. That implicitly pops it
101 // off the list of processes to be initialized/marked ready.
102 toFinalize.pushLast(p);
103 }
104}
105
106void
107Scheduler::yield()
108{
109 _current = readyList.getNext();
110 if (!_current) {
111 // There are no more processes, so return control to evaluate.
112 Fiber::primaryFiber()->run();
113 } else {
114 _current->popListNode();
115 // Switch to whatever Fiber is supposed to run this process. All
116 // Fibers which aren't running should be parked at this line.
117 _current->fiber()->run();
118 // If the current process needs to be manually started, start it.
119 if (_current && _current->needsStart())
120 _current->run();
121 }
122 if (_current && _current->excWrapper) {
123 // Make sure this isn't a method process.
124 assert(!_current->needsStart());
125 auto ew = _current->excWrapper;
126 _current->excWrapper = nullptr;
127 ew->throw_it();
128 }
129}
130
131void
132Scheduler::ready(Process *p)
133{
134 // Clump methods together to minimize context switching.
135 if (p->procKind() == ::sc_core::SC_METHOD_PROC_)
136 readyList.pushFirst(p);
137 else
138 readyList.pushLast(p);
139
140 scheduleReadyEvent();
141}
142
143void
144Scheduler::requestUpdate(Channel *c)
145{
146 updateList.pushLast(c);
147 if (eq)
148 scheduleReadyEvent();
149}
150
151void
152Scheduler::scheduleReadyEvent()
153{
154 // Schedule the evaluate and update phases.
155 if (!readyEvent.scheduled()) {
156 panic_if(!eq, "Need to schedule ready, but no event manager.\n");
157 eq->schedule(&readyEvent, eq->getCurTick());
158 if (starvationEvent.scheduled())
159 eq->deschedule(&starvationEvent);
160 }
161}
162
163void
164Scheduler::scheduleStarvationEvent()
165{
166 if (!starvationEvent.scheduled()) {
167 panic_if(!eq, "Need to schedule starvation event, "
168 "but no event manager.\n");
169 eq->schedule(&starvationEvent, eq->getCurTick());
170 if (readyEvent.scheduled())
171 eq->deschedule(&readyEvent);
172 }
173}
174
175void
176Scheduler::runReady()
177{
178 bool empty = readyList.empty();
179
180 // The evaluation phase.
181 do {
182 yield();
183 } while (!readyList.empty());
184
185 if (!empty)
186 _numCycles++;
187
188 // The update phase.
189 update();
190
191 if (starved() && !runToTime)
192 scheduleStarvationEvent();
193
| 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), initReady(false),
50 runOnce(false)
51{}
52
53void
54Scheduler::prepareForInit()
55{
56 for (Process *p = toFinalize.getNext(); p; p = toFinalize.getNext()) {
57 p->finalize();
58 p->popListNode();
59 }
60
61 for (Process *p = initList.getNext(); p; p = initList.getNext()) {
62 p->finalize();
63 p->popListNode();
64 p->ready();
65 }
66
67 for (auto ets: eventsToSchedule)
68 eq->schedule(ets.first, ets.second);
69 eventsToSchedule.clear();
70
71 if (_started)
72 eq->schedule(&maxTickEvent, maxTick);
73
74 initReady = true;
75}
76
77void
78Scheduler::reg(Process *p)
79{
80 if (initReady) {
81 // If we're past initialization, finalize static sensitivity.
82 p->finalize();
83 // Mark the process as ready.
84 p->ready();
85 } else {
86 // Otherwise, record that this process should be initialized once we
87 // get there.
88 initList.pushLast(p);
89 }
90}
91
92void
93Scheduler::dontInitialize(Process *p)
94{
95 if (initReady) {
96 // Pop this process off of the ready list.
97 p->popListNode();
98 } else {
99 // Push this process onto the list of processes which still need
100 // their static sensitivity to be finalized. That implicitly pops it
101 // off the list of processes to be initialized/marked ready.
102 toFinalize.pushLast(p);
103 }
104}
105
106void
107Scheduler::yield()
108{
109 _current = readyList.getNext();
110 if (!_current) {
111 // There are no more processes, so return control to evaluate.
112 Fiber::primaryFiber()->run();
113 } else {
114 _current->popListNode();
115 // Switch to whatever Fiber is supposed to run this process. All
116 // Fibers which aren't running should be parked at this line.
117 _current->fiber()->run();
118 // If the current process needs to be manually started, start it.
119 if (_current && _current->needsStart())
120 _current->run();
121 }
122 if (_current && _current->excWrapper) {
123 // Make sure this isn't a method process.
124 assert(!_current->needsStart());
125 auto ew = _current->excWrapper;
126 _current->excWrapper = nullptr;
127 ew->throw_it();
128 }
129}
130
131void
132Scheduler::ready(Process *p)
133{
134 // Clump methods together to minimize context switching.
135 if (p->procKind() == ::sc_core::SC_METHOD_PROC_)
136 readyList.pushFirst(p);
137 else
138 readyList.pushLast(p);
139
140 scheduleReadyEvent();
141}
142
143void
144Scheduler::requestUpdate(Channel *c)
145{
146 updateList.pushLast(c);
147 if (eq)
148 scheduleReadyEvent();
149}
150
151void
152Scheduler::scheduleReadyEvent()
153{
154 // Schedule the evaluate and update phases.
155 if (!readyEvent.scheduled()) {
156 panic_if(!eq, "Need to schedule ready, but no event manager.\n");
157 eq->schedule(&readyEvent, eq->getCurTick());
158 if (starvationEvent.scheduled())
159 eq->deschedule(&starvationEvent);
160 }
161}
162
163void
164Scheduler::scheduleStarvationEvent()
165{
166 if (!starvationEvent.scheduled()) {
167 panic_if(!eq, "Need to schedule starvation event, "
168 "but no event manager.\n");
169 eq->schedule(&starvationEvent, eq->getCurTick());
170 if (readyEvent.scheduled())
171 eq->deschedule(&readyEvent);
172 }
173}
174
175void
176Scheduler::runReady()
177{
178 bool empty = readyList.empty();
179
180 // The evaluation phase.
181 do {
182 yield();
183 } while (!readyList.empty());
184
185 if (!empty)
186 _numCycles++;
187
188 // The update phase.
189 update();
190
191 if (starved() && !runToTime)
192 scheduleStarvationEvent();
193
|
195
196 if (runOnce) {
197 eq->reschedule(&maxTickEvent, eq->getCurTick());
198 runOnce = false;
199 }
200}
201
202void
203Scheduler::update()
204{
205 Channel *channel = updateList.getNext();
206 while (channel) {
207 channel->popListNode();
208 channel->update();
209 channel = updateList.getNext();
210 }
211}
212
213void
214Scheduler::pause()
215{
216 _paused = true;
217 kernel->status(::sc_core::SC_PAUSED);
218 runOnce = false;
219 scMain->run();
220
221 // If the ready event is supposed to run now, run it inline so that it
222 // preempts any delta notifications which were scheduled while we were
223 // paused.
224 if (readyEvent.scheduled()) {
225 eq->deschedule(&readyEvent);
226 runReady();
227 }
228}
229
230void
231Scheduler::stop()
232{
233 _stopped = true;
234 kernel->stop();
235 runOnce = false;
236 scMain->run();
237}
238
239void
240Scheduler::start(Tick max_tick, bool run_to_time)
241{
242 // We should be running from sc_main. Keep track of that Fiber to return
243 // to later.
244 scMain = Fiber::currentFiber();
245
246 _started = true;
247 _paused = false;
248 _stopped = false;
249 runToTime = run_to_time;
250
251 maxTick = max_tick;
252
253 if (starved() && !runToTime)
254 return;
255
256 if (initReady) {
257 kernel->status(::sc_core::SC_RUNNING);
258 eq->schedule(&maxTickEvent, maxTick);
259 }
260
261 // Return to gem5 to let it run events, etc.
262 Fiber::primaryFiber()->run();
263
264 if (pauseEvent.scheduled())
265 eq->deschedule(&pauseEvent);
266 if (stopEvent.scheduled())
267 eq->deschedule(&stopEvent);
268 if (maxTickEvent.scheduled())
269 eq->deschedule(&maxTickEvent);
270 if (starvationEvent.scheduled())
271 eq->deschedule(&starvationEvent);
272}
273
274void
275Scheduler::oneCycle()
276{
277 runOnce = true;
278 start(::MaxTick, false);
279}
280
281void
282Scheduler::schedulePause()
283{
284 if (pauseEvent.scheduled())
285 return;
286
287 eq->schedule(&pauseEvent, eq->getCurTick());
288}
289
290void
291Scheduler::scheduleStop(bool finish_delta)
292{
293 if (stopEvent.scheduled())
294 return;
295
296 if (!finish_delta) {
297 // If we're not supposed to finish the delta cycle, flush the list
298 // of ready processes and scheduled updates.
299 Process *p;
300 while ((p = readyList.getNext()))
301 p->popListNode();
302 Channel *c;
303 while ((c = updateList.getNext()))
304 c->popListNode();
305 }
306 eq->schedule(&stopEvent, eq->getCurTick());
307}
308
309Scheduler scheduler;
310
311} // namespace sc_gem5
| 198
199 if (runOnce) {
200 eq->reschedule(&maxTickEvent, eq->getCurTick());
201 runOnce = false;
202 }
203}
204
205void
206Scheduler::update()
207{
208 Channel *channel = updateList.getNext();
209 while (channel) {
210 channel->popListNode();
211 channel->update();
212 channel = updateList.getNext();
213 }
214}
215
216void
217Scheduler::pause()
218{
219 _paused = true;
220 kernel->status(::sc_core::SC_PAUSED);
221 runOnce = false;
222 scMain->run();
223
224 // If the ready event is supposed to run now, run it inline so that it
225 // preempts any delta notifications which were scheduled while we were
226 // paused.
227 if (readyEvent.scheduled()) {
228 eq->deschedule(&readyEvent);
229 runReady();
230 }
231}
232
233void
234Scheduler::stop()
235{
236 _stopped = true;
237 kernel->stop();
238 runOnce = false;
239 scMain->run();
240}
241
242void
243Scheduler::start(Tick max_tick, bool run_to_time)
244{
245 // We should be running from sc_main. Keep track of that Fiber to return
246 // to later.
247 scMain = Fiber::currentFiber();
248
249 _started = true;
250 _paused = false;
251 _stopped = false;
252 runToTime = run_to_time;
253
254 maxTick = max_tick;
255
256 if (starved() && !runToTime)
257 return;
258
259 if (initReady) {
260 kernel->status(::sc_core::SC_RUNNING);
261 eq->schedule(&maxTickEvent, maxTick);
262 }
263
264 // Return to gem5 to let it run events, etc.
265 Fiber::primaryFiber()->run();
266
267 if (pauseEvent.scheduled())
268 eq->deschedule(&pauseEvent);
269 if (stopEvent.scheduled())
270 eq->deschedule(&stopEvent);
271 if (maxTickEvent.scheduled())
272 eq->deschedule(&maxTickEvent);
273 if (starvationEvent.scheduled())
274 eq->deschedule(&starvationEvent);
275}
276
277void
278Scheduler::oneCycle()
279{
280 runOnce = true;
281 start(::MaxTick, false);
282}
283
284void
285Scheduler::schedulePause()
286{
287 if (pauseEvent.scheduled())
288 return;
289
290 eq->schedule(&pauseEvent, eq->getCurTick());
291}
292
293void
294Scheduler::scheduleStop(bool finish_delta)
295{
296 if (stopEvent.scheduled())
297 return;
298
299 if (!finish_delta) {
300 // If we're not supposed to finish the delta cycle, flush the list
301 // of ready processes and scheduled updates.
302 Process *p;
303 while ((p = readyList.getNext()))
304 p->popListNode();
305 Channel *c;
306 while ((c = updateList.getNext()))
307 c->popListNode();
308 }
309 eq->schedule(&stopEvent, eq->getCurTick());
310}
311
312Scheduler scheduler;
313
314} // namespace sc_gem5
|