Messages in this thread | | | Date | Wed, 2 Apr 2008 14:35:25 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH]: Fix SMP-reordering race in mark_buffer_dirty |
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On Wed, 2 Apr 2008, Linus Torvalds wrote: > > Core 2 is the outlier in having a noticeably faster "mfence" than atomic > instructions
Side note: mfence is probably faster than 6 cycles on Core 2. I've seen it be basically zero-cost. Try adding a few memory ops around it - the timing will probably change. Core 2 has this odd behaviour that it sometimes does worse on the *really* trivial things that don't happen in real life.
Linus
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