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#include "systemc/ext/utils/sc_report.hh"
38#include "systemc/ext/utils/sc_report_handler.hh"
|
40#include "systemc/utils/tracefile.hh"
41
42namespace sc_gem5
43{
44
45Scheduler::Scheduler() :
46 eq(nullptr), readyEvent(this, false, ReadyPriority),
47 pauseEvent(this, false, PausePriority),
48 stopEvent(this, false, StopPriority),
49 scMain(nullptr), _throwToScMain(nullptr),
50 starvationEvent(this, false, StarvationPriority),
51 _elaborationDone(false), _started(false), _stopNow(false),
52 _status(StatusOther), maxTickEvent(this, false, MaxTickPriority),
53 timeAdvancesEvent(this, false, TimeAdvancesPriority), _numCycles(0),
54 _changeStamp(0), _current(nullptr), initDone(false), runOnce(false)
55{}
56
57Scheduler::~Scheduler()
58{
59 // Clear out everything that belongs to us to make sure nobody tries to
60 // clear themselves out after the scheduler goes away.
61 clear();
62}
63
64void
65Scheduler::clear()
66{
67 // Delta notifications.
68 while (!deltas.empty())
69 deltas.front()->deschedule();
70
71 // Timed notifications.
72 for (auto &tsp: timeSlots) {
73 TimeSlot *&ts = tsp.second;
74 while (!ts->events.empty())
75 ts->events.front()->deschedule();
76 deschedule(ts);
77 }
78 timeSlots.clear();
79
80 // gem5 events.
81 if (readyEvent.scheduled())
82 deschedule(&readyEvent);
83 if (pauseEvent.scheduled())
84 deschedule(&pauseEvent);
85 if (stopEvent.scheduled())
86 deschedule(&stopEvent);
87 if (starvationEvent.scheduled())
88 deschedule(&starvationEvent);
89 if (maxTickEvent.scheduled())
90 deschedule(&maxTickEvent);
91 if (timeAdvancesEvent.scheduled())
92 deschedule(&timeAdvancesEvent);
93
94 Process *p;
95 while ((p = initList.getNext()))
96 p->popListNode();
97 while ((p = readyListMethods.getNext()))
98 p->popListNode();
99 while ((p = readyListThreads.getNext()))
100 p->popListNode();
101
102 Channel *c;
103 while ((c = updateList.getNext()))
104 c->popListNode();
105}
106
107void
108Scheduler::initPhase()
109{
110 for (Process *p = initList.getNext(); p; p = initList.getNext()) {
111 p->popListNode();
112
113 if (p->dontInitialize()) {
114 if (!p->hasStaticSensitivities() && !p->internal()) {
115 SC_REPORT_WARNING(
116 "(W558) disable() or dont_initialize() called on "
117 "process with no static sensitivity, it will be "
118 "orphaned", p->name());
119 }
120 } else {
121 p->ready();
122 }
123 }
124
125 runUpdate();
126 runDelta();
127
128 for (auto ets: eventsToSchedule)
129 eq->schedule(ets.first, ets.second);
130 eventsToSchedule.clear();
131
132 if (_started) {
133 if (!runToTime && starved())
134 scheduleStarvationEvent();
135 kernel->status(::sc_core::SC_RUNNING);
136 }
137
138 initDone = true;
139
140 status(StatusOther);
141
142 scheduleTimeAdvancesEvent();
143}
144
145void
146Scheduler::reg(Process *p)
147{
148 if (initDone) {
149 // If not marked as dontInitialize, mark as ready.
150 if (!p->dontInitialize())
151 p->ready();
152 } else {
153 // Otherwise, record that this process should be initialized once we
154 // get there.
155 initList.pushLast(p);
156 }
157}
158
159void
160Scheduler::yield()
161{
162 // Pull a process from the active list.
163 _current = getNextReady();
164 if (!_current) {
165 // There are no more processes, so return control to evaluate.
166 Fiber::primaryFiber()->run();
167 } else {
168 _current->popListNode();
169 // Switch to whatever Fiber is supposed to run this process. All
170 // Fibers which aren't running should be parked at this line.
171 _current->fiber()->run();
172 // If the current process needs to be manually started, start it.
173 if (_current && _current->needsStart()) {
174 _current->needsStart(false);
175 // If a process hasn't started yet, "resetting" it just starts it
176 // and signals its reset event.
177 if (_current->inReset())
178 _current->resetEvent().notify();
179 try {
180 _current->run();
181 } catch (...) {
182 throwToScMain();
183 }
184 }
185 }
186 if (_current && !_current->needsStart()) {
187 if (_current->excWrapper) {
188 auto ew = _current->excWrapper;
189 _current->excWrapper = nullptr;
190 ew->throw_it();
191 } else if (_current->inReset()) {
192 _current->reset(false);
193 }
194 }
195}
196
197void
198Scheduler::ready(Process *p)
199{
200 if (_stopNow)
201 return;
202
203 if (p->procKind() == ::sc_core::SC_METHOD_PROC_)
204 readyListMethods.pushLast(p);
205 else
206 readyListThreads.pushLast(p);
207
208 if (!inEvaluate())
209 scheduleReadyEvent();
210}
211
212void
213Scheduler::resume(Process *p)
214{
215 if (initDone)
216 ready(p);
217 else
218 initList.pushLast(p);
219}
220
221bool
222listContains(ListNode *list, ListNode *target)
223{
224 ListNode *n = list->nextListNode;
225 while (n != list)
226 if (n == target)
227 return true;
228 return false;
229}
230
231bool
232Scheduler::suspend(Process *p)
233{
234 bool was_ready;
235 if (initDone) {
236 // After initialization, check if we're on a ready list.
237 was_ready = (p->nextListNode != nullptr);
238 p->popListNode();
239 } else {
240 // Nothing is ready before init.
241 was_ready = false;
242 }
243 return was_ready;
244}
245
246void
247Scheduler::requestUpdate(Channel *c)
248{
249 updateList.pushLast(c);
250 if (!inEvaluate())
251 scheduleReadyEvent();
252}
253
254void
255Scheduler::scheduleReadyEvent()
256{
257 // Schedule the evaluate and update phases.
258 if (!readyEvent.scheduled()) {
259 schedule(&readyEvent);
260 if (starvationEvent.scheduled())
261 deschedule(&starvationEvent);
262 }
263}
264
265void
266Scheduler::scheduleStarvationEvent()
267{
268 if (!starvationEvent.scheduled()) {
269 schedule(&starvationEvent);
270 if (readyEvent.scheduled())
271 deschedule(&readyEvent);
272 }
273}
274
275void
276Scheduler::runReady()
277{
278 scheduleTimeAdvancesEvent();
279
280 bool empty = readyListMethods.empty() && readyListThreads.empty();
281 lastReadyTick = getCurTick();
282
283 // The evaluation phase.
284 status(StatusEvaluate);
285 do {
286 yield();
287 } while (getNextReady());
288 _current = nullptr;
289
290 if (!empty) {
291 _numCycles++;
292 _changeStamp++;
293 }
294
295 if (_stopNow) {
296 status(StatusOther);
297 return;
298 }
299
300 runUpdate();
301 if (!traceFiles.empty())
302 trace(true);
303 runDelta();
304
305 if (!runToTime && starved())
306 scheduleStarvationEvent();
307
308 if (runOnce)
309 schedulePause();
310
311 status(StatusOther);
312}
313
314void
315Scheduler::runUpdate()
316{
317 status(StatusUpdate);
318
319 try {
320 Channel *channel = updateList.getNext();
321 while (channel) {
322 channel->popListNode();
323 channel->update();
324 channel = updateList.getNext();
325 }
326 } catch (...) {
327 throwToScMain();
328 }
329}
330
331void
332Scheduler::runDelta()
333{
334 status(StatusDelta);
335
336 try {
337 while (!deltas.empty())
338 deltas.back()->run();
339 } catch (...) {
340 throwToScMain();
341 }
342}
343
344void
345Scheduler::pause()
346{
347 status(StatusPaused);
348 kernel->status(::sc_core::SC_PAUSED);
349 runOnce = false;
350 if (scMain && !scMain->finished())
351 scMain->run();
352}
353
354void
355Scheduler::stop()
356{
357 status(StatusStopped);
358 kernel->stop();
359
360 clear();
361
362 runOnce = false;
363 if (scMain && !scMain->finished())
364 scMain->run();
365}
366
367void
368Scheduler::start(Tick max_tick, bool run_to_time)
369{
370 // We should be running from sc_main. Keep track of that Fiber to return
371 // to later.
372 scMain = Fiber::currentFiber();
373
374 _started = true;
375 status(StatusOther);
376 runToTime = run_to_time;
377
378 maxTick = max_tick;
379 lastReadyTick = getCurTick();
380
381 if (initDone) {
382 if (!runToTime && starved())
383 scheduleStarvationEvent();
384 kernel->status(::sc_core::SC_RUNNING);
385 }
386
387 schedule(&maxTickEvent, maxTick);
388 scheduleTimeAdvancesEvent();
389
390 // Return to gem5 to let it run events, etc.
391 Fiber::primaryFiber()->run();
392
393 if (pauseEvent.scheduled())
394 deschedule(&pauseEvent);
395 if (stopEvent.scheduled())
396 deschedule(&stopEvent);
397 if (maxTickEvent.scheduled())
398 deschedule(&maxTickEvent);
399 if (starvationEvent.scheduled())
400 deschedule(&starvationEvent);
401
402 if (_throwToScMain) {
403 const ::sc_core::sc_report *to_throw = _throwToScMain;
404 _throwToScMain = nullptr;
405 throw *to_throw;
406 }
407}
408
409void
410Scheduler::oneCycle()
411{
412 runOnce = true;
413 scheduleReadyEvent();
414 start(::MaxTick, false);
415}
416
417void
418Scheduler::schedulePause()
419{
420 if (pauseEvent.scheduled())
421 return;
422
423 schedule(&pauseEvent);
424}
425
426void
427Scheduler::throwToScMain()
428{
429 ::sc_core::sc_report report = reportifyException();
430 _throwToScMain = &report;
431 status(StatusOther);
432 scMain->run();
433}
434
435void
436Scheduler::scheduleStop(bool finish_delta)
437{
438 if (stopEvent.scheduled())
439 return;
440
441 if (!finish_delta) {
442 _stopNow = true;
443 // If we're not supposed to finish the delta cycle, flush all
444 // pending activity.
445 clear();
446 }
447 schedule(&stopEvent);
448}
449
450void
451Scheduler::trace(bool delta)
452{
453 for (auto tf: traceFiles)
454 tf->trace(delta);
455}
456
457Scheduler scheduler;
458
459namespace {
460
461void
462throwingReportHandler(const ::sc_core::sc_report &r,
463 const ::sc_core::sc_actions &)
464{
465 throw r;
466}
467
468} // anonymous namespace
469
470const ::sc_core::sc_report
471reportifyException()
472{
|