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

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).