lkml.org 
[lkml]   [2009]   [Apr]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] x86: percpu_to_op() misses memory and flags clobbers
    Jeremy Fitzhardinge a écrit :
    > Eric Dumazet wrote:
    >> +#define percpu_inc(var) percpu_to_op0("inc", per_cpu__##var)
    >> +#define percpu_dec(var) percpu_to_op0("dec", per_cpu__##var)
    >>
    >
    > There's probably not a lot of value in this. The Intel and AMD
    > optimisation guides tend to deprecate inc/dec in favour of using
    > add/sub, because the former can cause pipeline stalls due to its partial
    > flags update.
    >
    > J

    Sure, but this saves one byte per call, this is probably why we still use
    inc/dec in so many places...

    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2009-04-01 20:51    [W:0.036 / U:30.716 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site