On Tue, Dec 23, 2014 at 01:46:58PM -0500, Rik van Riel wrote: > An uncontended futex is taken without ever going into kernel > space. Adaptive spinning allows short duration futexes to be > taken without going into kernel space. The going into kernel is a red herring afaict, a no-op syscall costs ~180 cycles or something like that. So sure you can do a wee spin (~90 cycles to try and amortize that), but I really doubt that this is the problem. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html