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SubjectRe: [PATCH 13/15] x86: add cmpxchg_flag() variant
On 08/23/2011 03:15 PM, Jeremy Fitzhardinge wrote:
>
> However, having prototyped it, I dunno, it doesn't really seem like much
> of a win for all the extra code it adds. I just can't get too excited
> about an extra test instruction adjacent to a monster like a locked
> cmpxchg. The jump variant avoids the test, but gcc still generates some
> pretty bogus stuff:
>

A compare is hardly a big cost, as you're quite correctly pointing out.

-hpa



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