The guy is a professional dev working on Linux, are you seriously suggesting he shouldn't know what "man" does? And are you seriously suggesting that searching

The guy is a professional dev working on Linux, are you seriously suggesting he shouldn't know what "man" does? And are you seriously suggesting that searching for "spin" is somehow arcane? https://www.google.com/search?q=linux+spin+lock+library https://www.google.com/search?q=linux+spin+lock+library pthread_spin_lock(3) is on the first page, along with a RH presentation which explains exactly why trying to roll your own userspace implementation is unlikely to be successful. The guy simply didn't do his homework, I have no idea why you are trying to defend him.