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    SubjectRe: [PATCH 13/15] x86: add cmpxchg_flag() variant
    On Tue, 23 Aug 2011, 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:

    There are also unlocked cmpxchges in use. And if the cmpxchg is a 16 byte
    cmpxchg (cmpxchg_double) then the comparison is getting more expensive.


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