Question on wait_for_one

[zcbenz]

My understanding of wait_for_one is: code calls it to wait for one task to finish, but the implementation seems to also stop waiting when there is new task (it waits on condition n_active_tasks() != n_tasks_old):

mlx/mlx/scheduler.h

Lines 127 to 135 in d699cc1

	void wait_for_one() {
	std::unique_lock<std::mutex> lk(mtx);
	int n_tasks_old = n_active_tasks();
	if (n_tasks_old > 1) {
	completion_cv.wait(lk, [this, n_tasks_old] {
	return this->n_active_tasks() != n_tasks_old;
	});
	}
	}

Why shouldn't the condition be n_active_tasks() < n_tasks_old?

[awni]

I'm not too sure why the condition is != istead of <. It does seem like a logic error. We can try the alternative just to be sure it works as expected.

[anonimity69]

If the goal is strictly waiting for a task to finish, then changing != to < makes sense.