There will not. QOS was a very large and intentional change, and it&#x27;s critical to getting great performance out of iOS and to make the fanless MacBook work at all.<p>In general, Apple has never encouraged anyone to use spinlocks, and as I mentioned at the end, as long as your critical section is really tiny and CPU-bound you&#x27;re unlikely to actually have a problem in practice. Note that spinlocks have always had a problem with priority inversion (OSSpinLock&#x27;s back-off algorithm is just to call syscall_thread_switch with a 1ms delay every 1024 iterations, which is not bad but doesn&#x27;t solve all priority inversions anyway).