[lkml]   [2007]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: O_DIRECT question
    Michael Tokarev wrote:
    > After all the explanations, I still don't see anything wrong with the
    > interface itself. O_DIRECT isn't "different semantics" - we're still
    > writing and reading some data. Yes, O_DIRECT and non-O_DIRECT usages
    > somewhat contradicts with each other, but there are other ways to make
    > the two happy, instead of introducing alot of stupid, complex, and racy
    > code all over.

    By the way. I just ran - for fun - a read test of a raid array.

    Reading blocks of size 512kbytes, starting at random places on a 400Gb
    array, doing 64threads.

    O_DIRECT: 336.73 MB/sec.
    !O_DIRECT: 146.00 MB/sec.

    Quite a... difference here.

    Using posix_fadvice() does not improve it.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2007-01-12 22:23    [W:0.028 / U:3.388 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site