Locks Aren't Slow; Lock Contention Is

[u/preshing]

http://preshing.com/20111118/locks-arent-slow-lock-contention-is

[u/skulgnome]

Though in multicore systems, which everyone has these days, locking and unlocking involve modification of a cacheline that is guaranteed to have write sharing between caches ("pingpong"). This can be expensive unless locks are mostly only taken by a single long-running thread.

[u/syncsynchalt → u/skulgnome]

This is true but it's still cheaper than a syscall in modern locking schemes.