On 08/28/2007 06:27 PM, Siddha, Suresh B wrote:
> On Mon, Aug 27, 2007 at 12:31:03PM -0700, Siddha, Suresh B wrote:
>> Essentially I observed that nice 0 tasks still endup on two cores of same
>> package, with out getting spread out to two different packages. This behavior
>> is same with out this fix and this fix doesn't help in any way.
>
> Ingo, Appended patch seems to fix the issue and as far as I can test, seems ok
> to me.
>
> This is a quick fix for .23. Peter Williams and myself plan to look at
> code cleanups in this area (HT/MC optimizations) post .23
>
> BTW, with this fix, do you want to retain the current FUZZ value?
>
> thanks,
> suresh
> --
>
> Try to fix MC/HT scheduler optimization breakage again, with out breaking
> the FUZZ logic.
>
> First fix the check
> if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task)
> with this
> if (*imbalance < busiest_load_per_task)
>
> As the current check is always false for nice 0 tasks (as
> SCHED_LOAD_SCALE_FUZZ
> is same as busiest_load_per_task for nice 0 tasks).
>
> With the above change, imbalance was getting reset to 0 in the corner case
> condition, making the FUZZ logic fail. Fix it by not corrupting the
> imbalance and change the imbalance, only when it finds that the
> HT/MC optimization is needed.
>
> Signed-off-by: Suresh Siddha <[EMAIL PROTECTED]>
> ---
>
> diff --git a/kernel/sched.c b/kernel/sched.c
> index 9fe473a..03e5e8d 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -2511,7 +2511,7 @@ group_next:
> * a think about bumping its value to force at least one task to be
> * moved
> */
> - if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task) {
> + if (*imbalance < busiest_load_per_task) {
> unsigned long tmp, pwr_now, pwr_move;
> unsigned int imbn;
>
> @@ -2563,10 +2563,8 @@ small_imbalance:
> pwr_move /= SCHED_LOAD_SCALE;
>
> /* Move if we gain throughput */
> - if (pwr_move <= pwr_now)
> - goto out_balanced;
> -
> - *imbalance = busiest_load_per_task;
> + if (pwr_move > pwr_now)
> + *imbalance = busiest_load_per_task;
> }
>
> return busiest;
Seems this didn't get merged? Latest git as of today still has the code
as it was before this patch.
-
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