lkml.org 
[lkml]   [2010]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Subject[patch 0/12] sched: fastpath cycle recovery
    From
    Date
    Hi Peter,

    The following patchlets take a pinned pipe-test context switch frequency
    in tip from 663KHZ to 694KHZ, and an unpinned instance from 450KHz to
    540KHz. With these applied to tip.today, I have zero 31-12->today
    regressions, and even some modest progressions.

    The biggest difference is made by the first patch. We have a problem
    with nohz when waking cross-cpu, which given select_idle_sibling(), we
    do quite a bit. In testing netperf TCP_RR, hitting nohz code on every
    micro-idle was eating ~10% of throughput, making cross-cpu wakeup a
    loser. These patchlets combined turned netperf TCP_RR cross-cpu vs
    affine from big loser into a winner.

    All of these are trivial, mostly axe murder, but cycles add up.

    -Mike



    \
     
     \ /
      Last update: 2010-03-11 10:51    [W:3.387 / U:0.076 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site