Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation

David S. Miller
2005-12-17T23:05:35Z

From: Richard Henderson <rth@twiddle.net>
Date: Sat, 17 Dec 2005 14:38:24 -0800

> You might consider just beginning your loops like
>
> mov zero, old
> cas [mem], zero, old
>
> to do the initial read, since old will now contain the
> contents of the memory, and we havn't changed the memory.

CAS is 32 cycles minimum on sparc64 even on a cache hit, so I think
the prefetch+load will be faster :-) But it deserves checking out,
that's for sure.

Either way, that is a clever use of CAS :)