[lkml]   [2001]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: reschedule_idle changes in ac kernels
    I ran the VolanoMark and TPC-H benchmarks on an 8 CPU system
    to observe the differences when changing the value at which
    preemptions are triggered. I used the 2.4.5 kernel as a basis
    and only changed the 'max_prio = ' statement in reschedule_idle()
    to change the preemption trigger threshold. In the 2.4.5 kernel
    the value of max_prio is set to 1.

    The results:

    In VolanoMark, changing the preemption trigger from 1 to 0
    resulted in a 4% drop in throughput.

    In TPC-H there was virtually no difference when going from
    1 to 0. If anything, the results were slightly better with
    0 as a threshold value as opposed to 1.

    My guess is that the threshold value was changed from 0 to
    1 in the 2.4 kernel for better performance with some workload.
    Anyone remember what that workload was/is?

    Mike Kravetz
    IBM Linux Technology Center
    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: 2005-03-22 13:17    [W:0.027 / U:0.080 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site