On: The Fastest Mutexes

[xxs]

start with few attempts w/o pause, just busy CAS, then CAS + pause, then yield (and backoff/sleep with random duration)

[senderista → xxs]

No, you shouldn’t be calling CAS in a tight loop, but rather a relaxed load to check if a CAS might be successful, with PAUSE equivalent after each load. After spinning for ~context switch latency you should back off with sched_yield before retrying the spin loop (and eventually start sleeping on backoff with exponential jitter etc).

[xxs → senderista]

of course, there is very rarely any a naked CAS