From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: David Miller <davem@davemloft.net>
Subject: Re: [tbench regression fixes]: digging out smelly deadmen.
Date: Sun, 26 Oct 2008 12:33:41 +0100
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Cc: mingo@elte.hu, s0mbre@tservice.net.ru, a.p.zijlstra@chello.nl,
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References: <200810250025.35734.rjw@sisk.pl> <200810251313.21120.rjw@sisk.pl> <20081025.205501.193695937.davem@davemloft.net>
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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
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