lkml.org 
[lkml]   [2007]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 2.6.21-rc3-mm2 4/4] sys_futex64 : allows 64bit futexes
    Andrew Morton wrote:
    > Well OK. But that doesn't actually explain why 64-bit mutexes are needed.
    > It just says they are required.

    I can show you the code but it's not easy to understand. For
    complicated syn objects like rwlocks the state information is more than
    just locked or not. Currently we have to use internal locks, modify the
    state information, and then release it. This is terribly inefficient
    when many threads are used. With 64bit futexes the state information
    can be kept in the futex object and we don't need an internal lock,
    hence the speed-up.

    --
    ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖

    [unhandled content-type:application/pgp-signature]
    \
     
     \ /
      Last update: 2007-03-15 20:39    [W:2.822 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site