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    SubjectRe: oltp ~10% regression with 2.6.27-rc5 on stoakley machine
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    > > > Thats bizarre... that just indicates the better clock, which should give
    > > > better (read fairer) scheduling hurts your workload.
    > > >
    > > > Is there anything I can run to see if we can fix the scheduler perhaps?
    > >
    > > I observed schedstats of sysbench, there's more
    > > "nr_failed_migrations_hot"
    > >
    > > 2.6.27-rc4: se.nr_failed_migrations_hot 11
    > > 2.6.27-rc5: se.nr_failed_migrations_hot 95
    > >
    > > task migration failed because of task_hot, the system is un-balanced?
    >
    > Ah, that makes sense, a more accurate clock could indeed make more tasks
    > hot.
    >
    > Can you try fiddling with: /proc/sys/kernel/sched_migration_cost ?

    sched_migration_cost regression
    ---------------------- -------------
    50000 ~6%
    0 ~8%
    500000 (default) ~10%
    5000000 ~14%
    -1 ~19%

    >
    > Also, we used to have some auto-tuning in there, which dissapeared some
    > time ago, gregory brought it back to live recently, perhaps he likes to
    > share? :-)
    >



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