void TaskScheduler::MainFiberStart(intptr_t arg) {
MainFiberStartArgs *mainFiberArgs = reinterpret_cast<MainFiberStartArgs *>(arg);
TaskScheduler *taskScheduler = mainFiberArgs->taskScheduler;
// Call the main task procedure
mainFiberArgs->MainTask(taskScheduler, mainFiberArgs->Arg);
// Request that all the threads quit
taskScheduler->m_quit.store(true, std::memory_order_release);
// Switch to the thread fibers
ThreadLocalStorage &tls = taskScheduler->m_tls[taskScheduler->GetCurrentThreadIndex()];
taskScheduler->m_fibers[tls.CurrentFiberIndex].SwitchToFiber(&tls.ThreadFiber);
// We should never get here
printf("Error: FiberStart should never return");
}
void TaskScheduler::FiberStart(intptr_t arg) {
TaskScheduler *taskScheduler = reinterpret_cast<TaskScheduler *>(arg);
while (!taskScheduler->m_quit.load(std::memory_order_acquire)) {
// Clean up from the last fiber to run on this thread
taskScheduler->CleanUpOldFiber();
// Check if any of the waiting tasks are ready
std::size_t waitingFiberIndex = FTL_INVALID_INDEX;
for (std::size_t i = 0; i < taskScheduler->m_fiberPoolSize; ++i) {
// Double lock
if (!taskScheduler->m_waitingFibers[i].load(std::memory_order_relaxed)) {
continue;
}
if (!taskScheduler->m_waitingFibers[i].load(std::memory_order_acquire)) {
continue;
}
// Found a waiting fiber
// Test if it's ready
WaitingBundle *bundle = &taskScheduler->m_waitingBundles[i];
if (bundle->Counter->load(std::memory_order_relaxed) != bundle->TargetValue) {
continue;
}
bool expected = true;
if (std::atomic_compare_exchange_weak_explicit(&taskScheduler->m_waitingFibers[i], &expected, false, std::memory_order_release, std::memory_order_relaxed)) {
waitingFiberIndex = i;
break;
}
}
if (waitingFiberIndex != FTL_INVALID_INDEX) {
// Found a waiting task that is ready to continue
ThreadLocalStorage &tls = taskScheduler->m_tls[taskScheduler->GetCurrentThreadIndex()];
tls.OldFiberIndex = tls.CurrentFiberIndex;
tls.CurrentFiberIndex = waitingFiberIndex;
tls.OldFiberDestination = FiberDestination::ToPool;
// Switch
taskScheduler->m_fibers[tls.OldFiberIndex].SwitchToFiber(&taskScheduler->m_fibers[tls.CurrentFiberIndex]);
// And we're back
} else {
// Get a new task from the queue, and execute it
TaskBundle nextTask;
if (!taskScheduler->GetNextTask(&nextTask)) {
// Spin
} else {
nextTask.TaskToExecute.Function(taskScheduler, nextTask.TaskToExecute.ArgData);
nextTask.Counter->fetch_sub(1);
}
}
}
// Start the quit sequence
// Switch to the thread fibers
ThreadLocalStorage &tls = taskScheduler->m_tls[taskScheduler->GetCurrentThreadIndex()];
taskScheduler->m_fibers[tls.CurrentFiberIndex].SwitchToFiber(&tls.ThreadFiber);
// We should never get here
printf("Error: FiberStart should never return");
}
