[lkml]   [2010]   [Aug]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    Subject[RFC PATCH 00/11] sched: CFS low-latency features

    Following the findings I presented a few months ago
    ( about CFS having large vruntime spread
    issues, Peter Zijlstra and I pursued the discussion and the implementation
    effort (my work on this is funded by Nokia). I recently put the result together
    and came up with this patchset, combining both his work and mine.

    With this patchset, I got the following results with wakeup-latency.c (a 10ms
    periodic timer), running, Xorg, make -j3 and firefox (playing a
    youtube video), with Xorg moving terminal windows around, in parallel on a UP
    system (links to the test program source in the dyn min_vruntime patch). The
    Xorg interactivity is very good with the new features enabled, but was poor
    originally with the vanilla mainline scheduler. The 10ms timer delays are as
    follow: mainline* with low-latency features**
    maximum latency: 34465.2 µs 8261.4 µs
    average latency: 6445.5 µs 211.2 µs
    missed timer events: yes no

    * mainline test needs to run for a few minutes first
    to let it rip the spread apart.

    ** low-latency features:

    with the patchset applied and CONFIG_SCHED_DEBUG=y
    (with debugfs mounted in /sys/debugfs)

    for opt in DYN_MIN_VRUNTIME \
    do echo $opt > /sys/debugfs/sched_features;

    These patches are designed to allow individual enabling of each feature and to
    make sure that the object size of sched.o does not grow when the features are
    disabled on a CONFIG_SCHED_DEBUG=n kernel. Optimization of the try_to_wake_up()
    fast path when features are enabled could be done later by merging some of these
    features together. This patchset is based on

    Feedback is welcome,



    Mathieu Desnoyers
    Operating System Efficiency R&D Consultant
    EfficiOS Inc.
    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: 2010-08-26 20:19    [W:0.021 / U:0.548 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site