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    SubjectRe: [patch 5/12] sched: tweak sched_latency and min_granularity
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    sched: tweak sched_latency and min_granularity

    Allow LAST_BUDDY to kick in sooner, improving cache utilization as soon as
    a second buddy pair arrives on scene. The cost is latency starting to climb
    sooner, the tbenefit for tbench 8 on my Q6600 box is ~2%. No detrimental
    effects noted in normal idesktop usage.

    Signed-off-by: Mike Galbraith <efault@gmx.de>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    LKML-Reference: <new-submission>

    ---
    kernel/sched_fair.c | 12 ++++++------
    1 file changed, 6 insertions(+), 6 deletions(-)

    Index: linux-2.6/kernel/sched_fair.c
    ===================================================================
    --- linux-2.6.orig/kernel/sched_fair.c
    +++ linux-2.6/kernel/sched_fair.c
    @@ -35,8 +35,8 @@
    * (to see the precise effective timeslice length of your workload,
    * run vmstat and monitor the context-switches (cs) field)
    */
    -unsigned int sysctl_sched_latency = 5000000ULL;
    -unsigned int normalized_sysctl_sched_latency = 5000000ULL;
    +unsigned int sysctl_sched_latency = 6000000ULL;
    +unsigned int normalized_sysctl_sched_latency = 6000000ULL;

    /*
    * The initial- and re-scaling of tunables is configurable
    @@ -52,15 +52,15 @@ enum sched_tunable_scaling sysctl_sched_

    /*
    * Minimal preemption granularity for CPU-bound tasks:
    - * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
    + * (default: 2 msec * (1 + ilog(ncpus)), units: nanoseconds)
    */
    -unsigned int sysctl_sched_min_granularity = 1000000ULL;
    -unsigned int normalized_sysctl_sched_min_granularity = 1000000ULL;
    +unsigned int sysctl_sched_min_granularity = 2000000ULL;
    +unsigned int normalized_sysctl_sched_min_granularity = 2000000ULL;

    /*
    * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
    */
    -static unsigned int sched_nr_latency = 5;
    +static unsigned int sched_nr_latency = 3;

    /*
    * After fork, child runs first. If set to 0 (default) then



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