If multiple cores are trying to do atomic operations on the same value, the hardware typically is not fair. For mutexes, it depends on whether the operating sys

If multiple cores are trying to do atomic operations on the same value, the hardware typically is not fair. For mutexes, it depends on whether the operating system wakes up waiters in a fair way. Often that is not fully fair either. If there are only two threads at most, you can sometimes use a different algorithm than if you have an arbitrary number of threads (for example, for single-producer, single-consumer queues, lockless is typically better than with a mutex). You should of course benchmark your particular problem to see what solution is actually faster.