void ThreadPool::run()
{
for (uint8 x=0; x<m_uiCount; x++)
{
ThreadPoolThread *thread = new ThreadPoolThread(this, false);
thread->onCompleteEvent += delegate(this, &ThreadPool::onThreadComplete);
m_vThreadList.push_back( thread );
thread->start();
}
while (!isStopped())
{
doPause();
removedForced();
uint32 runTaskCount = activeThreads();
if (runTaskCount < m_uiCount)
startNewTasks();
runTaskCount = activeThreads();
if ((runTaskCount == m_uiCount || m_vTaskList.empty()) && !isStopped())
m_WaitCondition.wait();
}
}
void ThreadPool::purgeTasks()
{
{
m_TaskMutex.lock();
m_ThreadMutex.readLock();
for (size_t x=0; x<m_vThreadList.size(); x++)
{
m_vThreadList[x]->stopTask();
}
m_ThreadMutex.readUnlock();
m_ForcedMutex.writeLock();
for (size_t x=0; x<m_vForcedList.size(); x++)
{
m_vForcedList[x]->stop();
m_vForcedList[x]->onCompleteEvent -= delegate(this, &ThreadPool::onThreadComplete);
}
safe_delete(m_vForcedList);
m_ForcedMutex.writeUnlock();
safe_delete(m_vTaskList);
m_TaskMutex.unlock();
}
while (activeThreads() > 0)
gcSleep(50);
}
void WorkQueue::concurrentApply(size_t iterations, WTF::Function<void (size_t index)>&& function)
{
if (!iterations)
return;
if (iterations == 1) {
function(0);
return;
}
class ThreadPool {
public:
ThreadPool()
{
// We don't need a thread for the current core.
unsigned threadCount = numberOfProcessorCores() - 1;
m_workers.reserveInitialCapacity(threadCount);
for (unsigned i = 0; i < threadCount; ++i) {
m_workers.append(Thread::create("ThreadPool Worker", [this] {
threadBody();
}));
}
}
size_t workerCount() const { return m_workers.size(); }
void dispatch(const WTF::Function<void ()>* function)
{
LockHolder holder(m_lock);
m_queue.append(function);
m_condition.notifyOne();
}
private:
NO_RETURN void threadBody()
{
while (true) {
const WTF::Function<void ()>* function;
{
LockHolder holder(m_lock);
m_condition.wait(m_lock, [this] {
return !m_queue.isEmpty();
});
function = m_queue.takeFirst();
}
(*function)();
}
}
Lock m_lock;
Condition m_condition;
Deque<const WTF::Function<void ()>*> m_queue;
Vector<Ref<Thread>> m_workers;
};
static LazyNeverDestroyed<ThreadPool> threadPool;
static std::once_flag onceFlag;
std::call_once(onceFlag, [] {
threadPool.construct();
});
// Cap the worker count to the number of iterations (excluding this thread)
const size_t workerCount = std::min(iterations - 1, threadPool->workerCount());
std::atomic<size_t> currentIndex(0);
std::atomic<size_t> activeThreads(workerCount + 1);
Condition condition;
Lock lock;
WTF::Function<void ()> applier = [&, function = WTFMove(function)] {
size_t index;
// Call the function for as long as there are iterations left.
while ((index = currentIndex++) < iterations)
function(index);
// If there are no active threads left, signal the caller.
if (!--activeThreads) {
LockHolder holder(lock);
condition.notifyOne();
}
};
for (size_t i = 0; i < workerCount; ++i)
threadPool->dispatch(&applier);
applier();
LockHolder holder(lock);
condition.wait(lock, [&] { return !activeThreads; });
}
