Class Barrier

src/engine/Engine.cpp:35–66

Multiple-phase barrier based on C++ mutexes, as a reference. */

/** Multiple-phase barrier based on C++ mutexes, as a reference.
*/
struct Barrier {
	size_t threads = 0;
	size_t count = 0;
	size_t phase = 0;

	std::mutex mutex;
	std::condition_variable cv;

	void setThreads(size_t threads) {
		this->threads = threads;
	}

	void wait() {
		std::unique_lock<std::mutex> lock(mutex);
		size_t currentPhase = phase;

		// Check if we're the last thread.
		if (++count >= threads) {
			// Advance phase and reset count
			count = 0;
			phase++;
			// Notify all other threads
			cv.notify_all();
			return;
		}

		// Unlock and wait on phase to change
		cv.wait(lock, [&] {
			return phase != currentPhase;
		});
	}
};


/** Multiple-phase barrier based on spin-locking.