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    SubjectRe: [PATCH 5/5] sched: make fix_small_imbalance work with asymmetric packing
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    On Fri, 2010-04-09 at 16:21 +1000, Michael Neuling wrote:
    > With the asymmetric packing infrastructure, fix_small_imbalance is
    > causing idle higher threads to pull tasks off lower threads.
    >
    > This is being caused by an off-by-one error.
    >
    > Signed-off-by: Michael Neuling <mikey@neuling.org>
    > ---
    > I'm not sure this is the right fix but without it, higher threads pull
    > tasks off the lower threads, then the packing pulls it back down, etc
    > etc and tasks bounce around constantly.

    Would help if you expand upon the why/how it manages to get pulled up.

    I can't immediately spot anything wrong with the patch, but then that
    isn't my favourite piece of code either.. Suresh, any comments?

    > ---
    >
    > kernel/sched_fair.c | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > Index: linux-2.6-ozlabs/kernel/sched_fair.c
    > ===================================================================
    > --- linux-2.6-ozlabs.orig/kernel/sched_fair.c
    > +++ linux-2.6-ozlabs/kernel/sched_fair.c
    > @@ -2652,7 +2652,7 @@ static inline void fix_small_imbalance(s
    > * SCHED_LOAD_SCALE;
    > scaled_busy_load_per_task /= sds->busiest->cpu_power;
    >
    > - if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
    > + if (sds->max_load - sds->this_load + scaled_busy_load_per_task >
    > (scaled_busy_load_per_task * imbn)) {
    > *imbalance = sds->busiest_load_per_task;
    > return;



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