This is kind of what I am talking about though. The whole point of async scheduling is that semaphores, locking, etc are unnecessary because you strictly control the CPU schedule and can dynamically rewrite the schedule such that the need for such mechanisms largely doesn't exist. This provides a qualitative performance boost for quite a few analytics and other workloads, which is the only reason we do it (since it is considerably more complex to implement).

If you aren't bothering to write a real scheduler then it becomes less clear why you would bother with true async. Lots of hassle for not much payoff.