lkml.org 
[lkml]   [2006]   [Mar]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Ocfs2 performance bugs of doom
    On Tue, Mar 07, 2006 at 04:34:12AM +0100, Andi Kleen wrote:
    > Did you actually do some statistics how long the hash chains are?
    > Just increasing hash tables blindly has other bad side effects, like
    > increasing cache misses.
    Yep, the gory details are at:

    http://oss.oracle.com/~mfasheh/lock_distribution.csv

    This measure was taken about 18,000 locks into a kernel untar. The only
    change was that I switched things to only hash the last 18 characters of
    lock resource names.

    In short things aren't so bad that a larger hash table wouldn't help. We've
    definitely got some peaks however. Our in-house laboratory of mathematicians
    (read: Bill Irwin) is checking out methods by which we can smooth things out
    a bit more :)
    --Mark

    --
    Mark Fasheh
    Senior Software Developer, Oracle
    mark.fasheh@oracle.com
    -
    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: 2006-03-07 06:02    [W:2.203 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site