FIBER_START_FUNCTION_CLASS_IMPL(TaskScheduler, FiberStart) {
GlobalArgs *globalArgs = reinterpret_cast<GlobalArgs *>(arg);
TaskScheduler *taskScheduler = &globalArgs->g_taskScheduler;
while (!taskScheduler->m_quit.load()) {
// Check if any of the waiting tasks are ready
WaitingTask waitingTask;
bool waitingTaskReady = false;
taskScheduler->m_waitingTaskLock.lock();
auto iter = taskScheduler->m_waitingTasks.begin();
for (; iter != taskScheduler->m_waitingTasks.end(); ++iter) {
if (iter->Counter->load() == iter->Value) {
waitingTaskReady = true;
break;
}
}
if (waitingTaskReady) {
waitingTask = *iter;
// Optimization for removing an item from a vector as suggested by ryeguy on reddit
// Explained here: http://stackoverflow.com/questions/4442477/remove-ith-item-from-c-stdvector/4442529#4442529
// Essentially, rather than forcing a memcpy to shift all the remaining elements down after the erase,
// we move the last element into the place where the erased element was. Then we pop off the last element
// Check that we're not already the last item
// Move assignment to self is not defined
if (iter != (--taskScheduler->m_waitingTasks.end())) {
*iter = std::move(taskScheduler->m_waitingTasks.back());
}
taskScheduler->m_waitingTasks.pop_back();
}
taskScheduler->m_waitingTaskLock.unlock();
if (waitingTaskReady) {
taskScheduler->SwitchFibers(waitingTask.Fiber);
}
TaskBundle nextTask;
if (!taskScheduler->GetNextTask(&nextTask)) {
std::this_thread::yield();
} else {
nextTask.TaskToExecute.Function(&globalArgs->g_taskScheduler, &globalArgs->g_heap, &globalArgs->g_allocator, nextTask.TaskToExecute.ArgData);
nextTask.Counter->fetch_sub(1);
}
}
FTLConvertFiberToThread(FTLGetCurrentFiber());
globalArgs->g_taskScheduler.m_numActiveWorkerThreads.fetch_sub(1);
FTLEndCurrentThread();
}
THREAD_FUNC_RETURN_TYPE TaskScheduler::ThreadStart(void *arg) {
ThreadStartArgs *threadArgs = reinterpret_cast<ThreadStartArgs *>(arg);
TaskScheduler *taskScheduler = threadArgs->taskScheduler;
uint index = threadArgs->threadIndex;
// Clean up
delete threadArgs;
// Get a free fiber to switch to
std::size_t freeFiberIndex = taskScheduler->GetNextFreeFiberIndex();
// Initialize tls
taskScheduler->m_tls[index].CurrentFiberIndex = freeFiberIndex;
// Switch
taskScheduler->m_tls[index].ThreadFiber.SwitchToFiber(&taskScheduler->m_fibers[freeFiberIndex]);
// And we've returned
// Cleanup and shutdown
FTLEndCurrentThread();
THREAD_FUNC_END;
}
