1 // The MIT License (MIT)
2 //
3 // 	Copyright (c) 2015 Sergey Makeev, Vadim Slyusarev
4 //
5 // 	Permission is hereby granted, free of charge, to any person obtaining a copy
6 // 	of this software and associated documentation files (the "Software"), to deal
7 // 	in the Software without restriction, including without limitation the rights
8 // 	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // 	copies of the Software, and to permit persons to whom the Software is
10 // 	furnished to do so, subject to the following conditions:
11 //
12 //  The above copyright notice and this permission notice shall be included in
13 // 	all copies or substantial portions of the Software.
14 //
15 // 	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // 	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // 	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // 	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // 	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // 	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // 	THE SOFTWARE.
22 
23 #include <MTScheduler.h>
24 #include <string.h> // for memset
25 
26 namespace MT
27 {
28 
29 #ifdef MT_INSTRUMENTED_BUILD
30 	TaskScheduler::TaskScheduler(uint32 workerThreadsCount, WorkerThreadParams* workerParameters, IProfilerEventListener* listener)
31 #else
32 	TaskScheduler::TaskScheduler(uint32 workerThreadsCount, WorkerThreadParams* workerParameters)
33 #endif
34 		: roundRobinThreadIndex(0)
35 		, startedThreadsCount(0)
36 	{
37 
38 #ifdef MT_INSTRUMENTED_BUILD
39 		profilerEventListener = listener;
40 #endif
41 
42 		if (workerThreadsCount != 0)
43 		{
44 			threadsCount.StoreRelaxed( MT::Clamp(workerThreadsCount, (uint32)1, (uint32)MT_MAX_THREAD_COUNT) );
45 		} else
46 		{
47 			//query number of processor
48 			threadsCount.StoreRelaxed( (uint32)MT::Clamp(Thread::GetNumberOfHardwareThreads() - 1, 1, (int)MT_MAX_THREAD_COUNT) );
49 		}
50 
51 		// create fiber pool (fibers with standard stack size)
52 		for (uint32 i = 0; i < MT_MAX_STANDART_FIBERS_COUNT; i++)
53 		{
54 			FiberContext& context = standartFiberContexts[i];
55 			context.fiber.Create(MT_STANDART_FIBER_STACK_SIZE, FiberMain, &context);
56 			bool res = standartFibersAvailable.TryPush( &context );
57 			MT_USED_IN_ASSERT(res);
58 			MT_ASSERT(res == true, "Can't add fiber to storage");
59 		}
60 
61 		// create fiber pool (fibers with extended stack size)
62 		for (uint32 i = 0; i < MT_MAX_EXTENDED_FIBERS_COUNT; i++)
63 		{
64 			FiberContext& context = extendedFiberContexts[i];
65 			context.fiber.Create(MT_EXTENDED_FIBER_STACK_SIZE, FiberMain, &context);
66 			bool res = extendedFibersAvailable.TryPush( &context );
67 			MT_USED_IN_ASSERT(res);
68 			MT_ASSERT(res == true, "Can't add fiber to storage");
69 		}
70 
71 
72 		for (int16 i = 0; i < TaskGroup::MT_MAX_GROUPS_COUNT; i++)
73 		{
74 			if (i != TaskGroup::DEFAULT)
75 			{
76 				bool res = availableGroups.TryPush( TaskGroup(i) );
77 				MT_USED_IN_ASSERT(res);
78 				MT_ASSERT(res == true, "Can't add group to storage");
79 			}
80 		}
81 
82 #if MT_GROUP_DEBUG
83 		groupStats[TaskGroup::DEFAULT].SetDebugIsFree(false);
84 #endif
85 
86 		// create worker thread pool
87 		int32 totalThreadsCount = GetWorkersCount();
88 		for (int32 i = 0; i < totalThreadsCount; i++)
89 		{
90 			threadContext[i].SetThreadIndex(i);
91 			threadContext[i].taskScheduler = this;
92 
93 			uint32 threadCore = i;
94 			ThreadPriority::Type priority = ThreadPriority::DEFAULT;
95 			if (workerParameters != nullptr)
96 			{
97 				const WorkerThreadParams& params = workerParameters[i];
98 
99 				threadCore = params.core;
100 				priority = params.priority;
101 			}
102 
103 			threadContext[i].thread.Start( MT_SCHEDULER_STACK_SIZE, WorkerThreadMain, &threadContext[i], threadCore, priority);
104 		}
105 	}
106 
107 
108 	TaskScheduler::~TaskScheduler()
109 	{
110 		int32 totalThreadsCount = GetWorkersCount();
111 		for (int32 i = 0; i < totalThreadsCount; i++)
112 		{
113 			threadContext[i].state.Store(internal::ThreadState::EXIT);
114 			threadContext[i].hasNewTasksEvent.Signal();
115 		}
116 
117 		for (int32 i = 0; i < totalThreadsCount; i++)
118 		{
119 			threadContext[i].thread.Join();
120 		}
121 	}
122 
123 	FiberContext* TaskScheduler::RequestFiberContext(internal::GroupedTask& task)
124 	{
125 		FiberContext *fiberContext = task.awaitingFiber;
126 		if (fiberContext)
127 		{
128 			task.awaitingFiber = nullptr;
129 			return fiberContext;
130 		}
131 
132 		MT::StackRequirements::Type stackRequirements = task.desc.stackRequirements;
133 
134 		fiberContext = nullptr;
135 		bool res = false;
136 		MT_USED_IN_ASSERT(res);
137 		switch(stackRequirements)
138 		{
139 		case MT::StackRequirements::STANDARD:
140 			res = standartFibersAvailable.TryPop(fiberContext);
141 			MT_ASSERT(res, "Can't get more standard fibers!");
142 			break;
143 		case MT::StackRequirements::EXTENDED:
144 			res = extendedFibersAvailable.TryPop(fiberContext);
145 			MT_ASSERT(res, "Can't get more extended fibers!");
146 			break;
147 		default:
148 			MT_REPORT_ASSERT("Unknown stack requrements");
149 		}
150 
151 		MT_ASSERT(fiberContext != nullptr, "Can't get more fibers. Too many tasks in flight simultaneously?");
152 
153 		fiberContext->currentTask = task.desc;
154 		fiberContext->currentGroup = task.group;
155 		fiberContext->parentFiber = task.parentFiber;
156 		fiberContext->stackRequirements = stackRequirements;
157 		return fiberContext;
158 	}
159 
160 	void TaskScheduler::ReleaseFiberContext(FiberContext*&& fiberContext)
161 	{
162 		MT_ASSERT(fiberContext, "Can't release nullptr Fiber. fiberContext is nullptr");
163 
164 		MT::StackRequirements::Type stackRequirements = fiberContext->stackRequirements;
165 		fiberContext->Reset();
166 
167 		MT_ASSERT(fiberContext != nullptr, "Fiber context can't be nullptr");
168 
169 		bool res = false;
170 		MT_USED_IN_ASSERT(res);
171 		switch(stackRequirements)
172 		{
173 		case MT::StackRequirements::STANDARD:
174 			res = standartFibersAvailable.TryPush(std::move(fiberContext));
175 			break;
176 		case MT::StackRequirements::EXTENDED:
177 			res = extendedFibersAvailable.TryPush(std::move(fiberContext));
178 			break;
179 		default:
180 			MT_REPORT_ASSERT("Unknown stack requrements");
181 		}
182 
183 		MT_USED_IN_ASSERT(res);
184 		MT_ASSERT(res != false, "Can't return fiber to storage");
185 	}
186 
187 	FiberContext* TaskScheduler::ExecuteTask(internal::ThreadContext& threadContext, FiberContext* fiberContext)
188 	{
189 		MT_ASSERT(threadContext.thread.IsCurrentThread(), "Thread context sanity check failed");
190 
191 		MT_ASSERT(fiberContext, "Invalid fiber context");
192 		MT_ASSERT(fiberContext->currentTask.IsValid(), "Invalid task");
193 
194 		// Set actual thread context to fiber
195 		fiberContext->SetThreadContext(&threadContext);
196 
197 		// Update task status
198 		fiberContext->SetStatus(FiberTaskStatus::RUNNED);
199 
200 		MT_ASSERT(fiberContext->GetThreadContext()->thread.IsCurrentThread(), "Thread context sanity check failed");
201 
202 		const void* poolUserData = fiberContext->currentTask.userData;
203 		TPoolTaskDestroy poolDestroyFunc = fiberContext->currentTask.poolDestroyFunc;
204 
205 #ifdef MT_INSTRUMENTED_BUILD
206 		threadContext.NotifyTaskEndExecute( MT_SYSTEM_TASK_COLOR, MT_SYSTEM_TASK_NAME );
207 #endif
208 
209 		// Run current task code
210 		Fiber::SwitchTo(threadContext.schedulerFiber, fiberContext->fiber);
211 
212 #ifdef MT_INSTRUMENTED_BUILD
213 		threadContext.NotifyTaskBeginExecute( MT_SYSTEM_TASK_COLOR, MT_SYSTEM_TASK_NAME );
214 #endif
215 
216 		// If task was done
217 		FiberTaskStatus::Type taskStatus = fiberContext->GetStatus();
218 		if (taskStatus == FiberTaskStatus::FINISHED)
219 		{
220 			//destroy task (call dtor) for "fire and forget" type of task from TaskPool
221 			if (poolDestroyFunc != nullptr)
222 			{
223 				poolDestroyFunc(poolUserData);
224 			}
225 
226 			TaskGroup taskGroup = fiberContext->currentGroup;
227 
228 			TaskScheduler::TaskGroupDescription  & groupDesc = threadContext.taskScheduler->GetGroupDesc(taskGroup);
229 
230 			// Update group status
231 			int groupTaskCount = groupDesc.Dec();
232 			MT_ASSERT(groupTaskCount >= 0, "Sanity check failed!");
233 			if (groupTaskCount == 0)
234 			{
235 				// Signal pending threads that group work is finished. Group can be destroyed after this call.
236 				groupDesc.Signal();
237 
238 				fiberContext->currentGroup = TaskGroup::INVALID;
239 			}
240 
241 			// Update total task count
242 			int allGroupTaskCount = threadContext.taskScheduler->allGroups.Dec();
243 			MT_ASSERT(allGroupTaskCount >= 0, "Sanity check failed!");
244 			if (allGroupTaskCount == 0)
245 			{
246 				// Notify all tasks in all group finished
247 				threadContext.taskScheduler->allGroups.Signal();
248 			}
249 
250 			FiberContext* parentFiberContext = fiberContext->parentFiber;
251 			if (parentFiberContext != nullptr)
252 			{
253 				int childrenFibersCount = parentFiberContext->childrenFibersCount.DecFetch();
254 				MT_ASSERT(childrenFibersCount >= 0, "Sanity check failed!");
255 
256 				if (childrenFibersCount == 0)
257 				{
258 					// This is a last subtask. Restore parent task
259 					MT_ASSERT(threadContext.thread.IsCurrentThread(), "Thread context sanity check failed");
260 					MT_ASSERT(parentFiberContext->GetThreadContext() == nullptr, "Inactive parent should not have a valid thread context");
261 
262 					// WARNING!! Thread context can changed here! Set actual current thread context.
263 					parentFiberContext->SetThreadContext(&threadContext);
264 
265 					MT_ASSERT(parentFiberContext->GetThreadContext()->thread.IsCurrentThread(), "Thread context sanity check failed");
266 
267 					// All subtasks is done.
268 					// Exiting and return parent fiber to scheduler
269 					return parentFiberContext;
270 				} else
271 				{
272 					// Other subtasks still exist
273 					// Exiting
274 					return nullptr;
275 				}
276 			} else
277 			{
278 				// Task is finished and no parent task
279 				// Exiting
280 				return nullptr;
281 			}
282 		}
283 
284 		MT_ASSERT(taskStatus != FiberTaskStatus::RUNNED, "Incorrect task status")
285 		return nullptr;
286 	}
287 
288 
289 	void TaskScheduler::FiberMain(void* userData)
290 	{
291 		FiberContext& fiberContext = *(FiberContext*)(userData);
292 		for(;;)
293 		{
294 			MT_ASSERT(fiberContext.currentTask.IsValid(), "Invalid task in fiber context");
295 			MT_ASSERT(fiberContext.GetThreadContext(), "Invalid thread context");
296 			MT_ASSERT(fiberContext.GetThreadContext()->thread.IsCurrentThread(), "Thread context sanity check failed");
297 
298 #ifdef MT_INSTRUMENTED_BUILD
299 			fiberContext.fiber.SetName( MT_SYSTEM_TASK_FIBER_NAME );
300 			fiberContext.GetThreadContext()->NotifyTaskBeginExecute( fiberContext.currentTask.debugColor, fiberContext.currentTask.debugID );
301 #endif
302 
303 			fiberContext.currentTask.taskFunc( fiberContext, fiberContext.currentTask.userData );
304 			fiberContext.SetStatus(FiberTaskStatus::FINISHED);
305 
306 #ifdef MT_INSTRUMENTED_BUILD
307 			fiberContext.fiber.SetName( MT_SYSTEM_TASK_FIBER_NAME );
308 			fiberContext.GetThreadContext()->NotifyTaskEndExecute( fiberContext.currentTask.debugColor, fiberContext.currentTask.debugID );
309 #endif
310 
311 			Fiber::SwitchTo(fiberContext.fiber, fiberContext.GetThreadContext()->schedulerFiber);
312 		}
313 
314 	}
315 
316 
317 	bool TaskScheduler::TryStealTask(internal::ThreadContext& threadContext, internal::GroupedTask & task, uint32 workersCount)
318 	{
319 		if (workersCount <= 1)
320 		{
321 			return false;
322 		}
323 
324 		uint32 victimIndex = threadContext.random.Get();
325 
326 		for (uint32 attempt = 0; attempt < workersCount; attempt++)
327 		{
328 			uint32 index = victimIndex % workersCount;
329 			if (index == threadContext.workerIndex)
330 			{
331 				victimIndex++;
332 				index = victimIndex % workersCount;
333 			}
334 
335 			internal::ThreadContext& victimContext = threadContext.taskScheduler->threadContext[index];
336 			if (victimContext.queue.TryPopNewest(task))
337 			{
338 				return true;
339 			}
340 
341 			victimIndex++;
342 		}
343 		return false;
344 	}
345 
346 
347 	void TaskScheduler::WorkerThreadMain( void* userData )
348 	{
349 		internal::ThreadContext& context = *(internal::ThreadContext*)(userData);
350 		MT_ASSERT(context.taskScheduler, "Task scheduler must be not null!");
351 
352 #ifdef MT_INSTRUMENTED_BUILD
353 		const char* threadNames[] = {"worker0","worker1","worker2","worker3","worker4","worker5","worker6","worker7","worker8","worker9","worker10","worker11","worker12"};
354 		if (context.workerIndex < MT_ARRAY_SIZE(threadNames))
355 		{
356 			Thread::SetThreadName(threadNames[context.workerIndex]);
357 		} else
358 		{
359 			Thread::SetThreadName("worker_thread");
360 		}
361 #endif
362 
363 		context.schedulerFiber.CreateFromCurrentThreadAndRun(SchedulerFiberMain, userData);
364 	}
365 
366 
367 	void TaskScheduler::SchedulerFiberMain( void* userData )
368 	{
369 		internal::ThreadContext& context = *(internal::ThreadContext*)(userData);
370 		MT_ASSERT(context.taskScheduler, "Task scheduler must be not null!");
371 
372 #ifdef MT_INSTRUMENTED_BUILD
373 		context.NotifyThreadCreate(context.workerIndex);
374 #endif
375 
376 		uint32 workersCount = context.taskScheduler->GetWorkersCount();
377 		int32 totalThreadsCount = context.taskScheduler->threadsCount.LoadRelaxed();
378 
379 		context.taskScheduler->startedThreadsCount.IncFetch();
380 
381 		//Simple spinlock until all threads is started and initialized
382 		for(;;)
383 		{
384 			int32 initializedThreadsCount = context.taskScheduler->startedThreadsCount.Load();
385 			if (initializedThreadsCount == totalThreadsCount)
386 			{
387 				break;
388 			}
389 
390 			// sleep some time until all other thread initialized
391 			Thread::Sleep(1);
392 		}
393 
394 		HardwareFullMemoryBarrier();
395 
396 #ifdef MT_INSTRUMENTED_BUILD
397 		context.NotifyThreadStart(context.workerIndex);
398 		context.NotifyTaskBeginExecute( MT_SYSTEM_TASK_COLOR, MT_SYSTEM_TASK_NAME );
399 #endif
400 
401 		while(context.state.Load() != internal::ThreadState::EXIT)
402 		{
403 			internal::GroupedTask task;
404 			if (context.queue.TryPopOldest(task) || TryStealTask(context, task, workersCount) )
405 			{
406 #ifdef MT_INSTRUMENTED_BUILD
407 				bool isNewTask = (task.awaitingFiber == nullptr);
408 #endif
409 
410 				// There is a new task
411 				FiberContext* fiberContext = context.taskScheduler->RequestFiberContext(task);
412 				MT_ASSERT(fiberContext, "Can't get execution context from pool");
413 				MT_ASSERT(fiberContext->currentTask.IsValid(), "Sanity check failed");
414 				MT_ASSERT(fiberContext->stackRequirements == task.desc.stackRequirements, "Sanity check failed");
415 
416 				while(fiberContext)
417 				{
418 #ifdef MT_INSTRUMENTED_BUILD
419 					if (isNewTask)
420 					{
421 						//TODO:
422 						isNewTask = false;
423 					}
424 #endif
425 					// prevent invalid fiber resume from child tasks, before ExecuteTask is done
426 					fiberContext->childrenFibersCount.IncFetch();
427 
428 					FiberContext* parentFiber = ExecuteTask(context, fiberContext);
429 
430 					FiberTaskStatus::Type taskStatus = fiberContext->GetStatus();
431 
432 					//release guard
433 					int childrenFibersCount = fiberContext->childrenFibersCount.DecFetch();
434 
435 					// Can drop fiber context - task is finished
436 					if (taskStatus == FiberTaskStatus::FINISHED)
437 					{
438 						MT_ASSERT( childrenFibersCount == 0, "Sanity check failed");
439 						context.taskScheduler->ReleaseFiberContext(std::move(fiberContext));
440 
441 						// If parent fiber is exist transfer flow control to parent fiber, if parent fiber is null, exit
442 						fiberContext = parentFiber;
443 					} else
444 					{
445 						MT_ASSERT( childrenFibersCount >= 0, "Sanity check failed");
446 
447 						// No subtasks here and status is not finished, this mean all subtasks already finished before parent return from ExecuteTask
448 						if (childrenFibersCount == 0)
449 						{
450 							MT_ASSERT(parentFiber == nullptr, "Sanity check failed");
451 						} else
452 						{
453 							// If subtasks still exist, drop current task execution. task will be resumed when last subtask finished
454 							break;
455 						}
456 
457 						// If task is in await state drop execution. task will be resumed when RestoreAwaitingTasks called
458 						if (taskStatus == FiberTaskStatus::AWAITING_GROUP)
459 						{
460 							break;
461 						}
462 					}
463 				} //while(fiberContext)
464 
465 			} else
466 			{
467 #ifdef MT_INSTRUMENTED_BUILD
468 				context.NotifyThreadIdleBegin(context.workerIndex);
469 #endif
470 
471 				// Queue if empty and stealing attempt failed
472 				// Wait for new events
473 				context.hasNewTasksEvent.Wait(2000);
474 
475 #ifdef MT_INSTRUMENTED_BUILD
476 				context.NotifyThreadIdleEnd(context.workerIndex);
477 #endif
478 
479 			}
480 
481 		} // main thread loop
482 
483 #ifdef MT_INSTRUMENTED_BUILD
484 		context.NotifyThreadStop(context.workerIndex);
485 #endif
486 
487 	}
488 
489 	void TaskScheduler::RunTasksImpl(ArrayView<internal::TaskBucket>& buckets, FiberContext * parentFiber, bool restoredFromAwaitState)
490 	{
491 		// This storage is necessary to calculate how many tasks we add to different groups
492 		int newTaskCountInGroup[TaskGroup::MT_MAX_GROUPS_COUNT];
493 
494 		// Default value is 0
495 		memset(&newTaskCountInGroup[0], 0, sizeof(newTaskCountInGroup));
496 
497 		// Set parent fiber pointer
498 		// Calculate the number of tasks per group
499 		// Calculate total number of tasks
500 		size_t count = 0;
501 		for (size_t i = 0; i < buckets.Size(); ++i)
502 		{
503 			internal::TaskBucket& bucket = buckets[i];
504 			for (size_t taskIndex = 0; taskIndex < bucket.count; taskIndex++)
505 			{
506 				internal::GroupedTask & task = bucket.tasks[taskIndex];
507 
508 				task.parentFiber = parentFiber;
509 
510 				int idx = task.group.GetValidIndex();
511 				MT_ASSERT(idx >= 0 && idx < TaskGroup::MT_MAX_GROUPS_COUNT, "Invalid index");
512 				newTaskCountInGroup[idx]++;
513 			}
514 
515 			count += bucket.count;
516 		}
517 
518 		// Increments child fibers count on parent fiber
519 		if (parentFiber)
520 		{
521 			parentFiber->childrenFibersCount.AddFetch((int)count);
522 		}
523 
524 		if (restoredFromAwaitState == false)
525 		{
526 			// Increase the number of active tasks in the group using data from temporary storage
527 			for (size_t i = 0; i < TaskGroup::MT_MAX_GROUPS_COUNT; i++)
528 			{
529 				int groupNewTaskCount = newTaskCountInGroup[i];
530 				if (groupNewTaskCount > 0)
531 				{
532 					groupStats[i].Reset();
533 					groupStats[i].Add((uint32)groupNewTaskCount);
534 				}
535 			}
536 
537 			// Increments all task in progress counter
538 			allGroups.Reset();
539 			allGroups.Add((uint32)count);
540 		} else
541 		{
542 			// If task's restored from await state, counters already in correct state
543 		}
544 
545 		// Add to thread queue
546 		for (size_t i = 0; i < buckets.Size(); ++i)
547 		{
548 			int bucketIndex = roundRobinThreadIndex.IncFetch() % threadsCount.LoadRelaxed();
549 			internal::ThreadContext & context = threadContext[bucketIndex];
550 
551 			internal::TaskBucket& bucket = buckets[i];
552 
553 			for(;;)
554 			{
555 				bool res = context.queue.Add(bucket.tasks, bucket.count);
556 				if (res == true)
557 				{
558 					break;
559 				}
560 
561 				//Can't add new tasks onto the queue. Look like the job system is overloaded. Wait some time and try again.
562 				//TODO: implement waiting until workers done using events.
563 				Thread::Sleep(10);
564 			}
565 
566 			context.hasNewTasksEvent.Signal();
567 		}
568 	}
569 
570 	void TaskScheduler::RunAsync(TaskGroup group, const TaskHandle* taskHandleArray, uint32 taskHandleCount)
571 	{
572 		MT_ASSERT(!IsWorkerThread(), "Can't use RunAsync inside Task. Use FiberContext.RunAsync() instead.");
573 
574 		ArrayView<internal::GroupedTask> buffer(MT_ALLOCATE_ON_STACK(sizeof(internal::GroupedTask) * taskHandleCount), taskHandleCount);
575 
576 		uint32 bucketCount = MT::Min((uint32)GetWorkersCount(), taskHandleCount);
577 		ArrayView<internal::TaskBucket> buckets(MT_ALLOCATE_ON_STACK(sizeof(internal::TaskBucket) * bucketCount), bucketCount);
578 
579 		internal::DistibuteDescriptions(group, taskHandleArray, buffer, buckets);
580 		RunTasksImpl(buckets, nullptr, false);
581 	}
582 
583 	bool TaskScheduler::WaitGroup(TaskGroup group, uint32 milliseconds)
584 	{
585 		MT_VERIFY(IsWorkerThread() == false, "Can't use WaitGroup inside Task. Use FiberContext.WaitGroupAndYield() instead.", return false);
586 
587 		TaskScheduler::TaskGroupDescription & groupDesc = GetGroupDesc(group);
588 
589 		return groupDesc.Wait(milliseconds);
590 	}
591 
592 	bool TaskScheduler::WaitAll(uint32 milliseconds)
593 	{
594 		MT_VERIFY(IsWorkerThread() == false, "Can't use WaitAll inside Task.", return false);
595 
596 		return allGroups.Wait(milliseconds);
597 	}
598 
599 	bool TaskScheduler::IsEmpty()
600 	{
601 		for (uint32 i = 0; i < MT_MAX_THREAD_COUNT; i++)
602 		{
603 			if (!threadContext[i].queue.IsEmpty())
604 			{
605 				return false;
606 			}
607 		}
608 		return true;
609 	}
610 
611 	int32 TaskScheduler::GetWorkersCount() const
612 	{
613 		return threadsCount.LoadRelaxed();
614 	}
615 
616 	bool TaskScheduler::IsWorkerThread() const
617 	{
618 		for (uint32 i = 0; i < MT_MAX_THREAD_COUNT; i++)
619 		{
620 			if (threadContext[i].thread.IsCurrentThread())
621 			{
622 				return true;
623 			}
624 		}
625 		return false;
626 	}
627 
628 	TaskGroup TaskScheduler::CreateGroup()
629 	{
630 		MT_ASSERT(IsWorkerThread() == false, "Can't use CreateGroup inside Task.");
631 
632 		TaskGroup group;
633 		if (!availableGroups.TryPop(group))
634 		{
635 			MT_REPORT_ASSERT("Group pool is empty");
636 		}
637 
638 		int idx = group.GetValidIndex();
639 		MT_USED_IN_ASSERT(idx);
640 		MT_ASSERT(groupStats[idx].GetDebugIsFree() == true, "Bad logic!");
641 #if MT_GROUP_DEBUG
642 		groupStats[idx].SetDebugIsFree(false);
643 #endif
644 
645 		return group;
646 	}
647 
648 	void TaskScheduler::ReleaseGroup(TaskGroup group)
649 	{
650 		MT_ASSERT(IsWorkerThread() == false, "Can't use ReleaseGroup inside Task.");
651 		MT_ASSERT(group.IsValid(), "Invalid group ID");
652 
653 		int idx = group.GetValidIndex();
654 		MT_USED_IN_ASSERT(idx);
655 		MT_ASSERT(groupStats[idx].GetDebugIsFree() == false, "Group already released");
656 #if MT_GROUP_DEBUG
657 		groupStats[idx].SetDebugIsFree(true);
658 #endif
659 
660 		bool res = availableGroups.TryPush(std::move(group));
661 		MT_USED_IN_ASSERT(res);
662 		MT_ASSERT(res, "Can't return group to pool");
663 	}
664 
665 	TaskScheduler::TaskGroupDescription & TaskScheduler::GetGroupDesc(TaskGroup group)
666 	{
667 		MT_ASSERT(group.IsValid(), "Invalid group ID");
668 
669 		int idx = group.GetValidIndex();
670 		TaskScheduler::TaskGroupDescription & groupDesc = groupStats[idx];
671 
672 		MT_ASSERT(groupDesc.GetDebugIsFree() == false, "Invalid group");
673 		return groupDesc;
674 	}
675 }
676 
677 
678