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    SubjectRe: PostgreSQL pgbench performance regression in 2.6.23+
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    On Fri, 2008-05-23 at 12:10 +0200, Ingo Molnar wrote:

    > if it's other tweaks as well then could you perhaps try to make
    > SCHED_BATCH batch more agressively?

    Running SCHED_BATCH with only the below put a large dent in the problem.

    You can have tl <= current->se.load.weight. Nothing good happens in
    either case, at least with this load.

    --- kernel/sched_fair.c.org 2008-05-23 14:59:39.000000000 +0200
    +++ kernel/sched_fair.c 2008-05-23 14:49:05.000000000 +0200
    @@ -1081,7 +1081,7 @@ wake_affine(struct rq *rq, struct sched_
    * effect of the currently running task from the load
    * of the current CPU:
    */
    - if (sync)
    + if (sync && tl > current->se.load.weight)
    tl -= current->se.load.weight;

    if ((tl <= load && tl + target_load(prev_cpu, idx) <= tl_per_task) ||


    2.6.26-smp x86_64
    1 9209.503213
    2 15792.406916
    3 23369.199181
    4 23140.108032
    5 24556.515470
    6 24926.457776
    8 26896.607558
    10 27350.988396
    15 29005.426298
    20 28558.267290
    30 27002.328374
    40 25809.202374
    50 24589.478654



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