[viega]

As the article says, the futex system call is overly complicated. But one shouldn't downplay its importance. Every major OS has had a slimmed down equivalent for about a decade, and the futex is at the core of any good modern lock.

Many things are obvious after, but there was plenty of time before for other people to do the same thing, it's not like we didn't know sysv semaphores didn't scale well.

"ad hoc" feels like an opinion here. My opinion is that when separation of concerns leads to big gains like the futex did, that's elegant, and an achievement. No need to diminish the good work done!