Re: [tbench regression fixes]: digging out smelly deadmen.

Rafael J. Wysocki
2008-10-26T11:29:25Z

On Sunday, 26 of October 2008, David Miller wrote:
> From: "Rafael J. Wysocki" <rjw@sisk.pl>
> Date: Sat, 25 Oct 2008 13:13:20 +0200
>
> > Could you please give me a pointer to the commit disabling the hrtimer feature?
>
> Here it is:

Thanks a lot!

> commit 0c4b83da58ec2e96ce9c44c211d6eac5f9dae478
> Author: Ingo Molnar <mingo@elte.hu>
> Date: Mon Oct 20 14:27:43 2008 +0200
>
> sched: disable the hrtick for now
>
> David Miller reported that hrtick update overhead has tripled the
> wakeup overhead on Sparc64.
>
> That is too much - disable the HRTICK feature for now by default,
> until a faster implementation is found.
>
> Reported-by: David Miller <davem@davemloft.net>
> Acked-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
> diff --git a/kernel/sched_features.h b/kernel/sched_features.h
> index 7c9e8f4..fda0162 100644
> --- a/kernel/sched_features.h
> +++ b/kernel/sched_features.h
> @@ -5,7 +5,7 @@ SCHED_FEAT(START_DEBIT, 1)
> SCHED_FEAT(AFFINE_WAKEUPS, 1)
> SCHED_FEAT(CACHE_HOT_BUDDY, 1)
> SCHED_FEAT(SYNC_WAKEUPS, 1)
> -SCHED_FEAT(HRTICK, 1)
> +SCHED_FEAT(HRTICK, 0)
> SCHED_FEAT(DOUBLE_TICK, 0)
> SCHED_FEAT(ASYM_GRAN, 1)
> SCHED_FEAT(LB_BIAS, 1)

Rafael