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

[David S. Miller]

From: Richard Henderson <rth@xxxxxxxxxxx>
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 :)
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