4 ms·

http://www.feyrer.de/NetBSD/gmcgarry/ http://www.feyrer.de/NetBSD/gmcgarry/ suggests that the cost to acquire an uncontested mutex on NetBSD in 2005 was ~37 nse

by neilc 17y ago

http://www.feyrer.de/NetBSD/gmcgarry/ http://www.feyrer.de/NetBSD/gmcgarry/ suggests that the cost to acquire an uncontested mutex on NetBSD in 2005 was ~37 nsec, so ~25 nsec doesn't seem too unreasonable (although strangely it was more expensive on FreeBSD).

Freaky 17y ago
> although strangely it was more expensive on FreeBSD I think mutex ops in 5.3 depended on syscalls or so. I distinctly remember a commit reducing mutex overheads by moving more of it into userspace, somewhat like futex I guess.