Also am I understanding it correctly that n is the number of threads in your example? Don't you find it suspicious that the number of operations goes up as the thread count goes up?

edit: ok, you are saying that under heavy contention the check avoids having to do the store at all. This is racy, and whether this is correct or not, would be very application specific.

edit2: I thought about this a bit, and I'm not sure i can come up with a scenario where the race matters...

edit3: ... as long as all threads are only doing atomic_max operations on the memory location, which an implementation can't assume.