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From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>,
	Mike Galbraith <efault@gmx.de>, Ingo Molnar <mingo@elte.hu>,
	Srivatsa Vaddagiri <vatsa@in.ibm.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched: revert load_balance_monitor()
Date: Mon, 25 Feb 2008 16:53:01 +0100	[thread overview]
Message-ID: <20080225155301.GA6787@osiris.boeblingen.de.ibm.com> (raw)
In-Reply-To: <1203953282.6242.180.camel@lappy>

On Mon, Feb 25, 2008 at 04:28:02PM +0100, Peter Zijlstra wrote:
> On Mon, 2008-02-25 at 20:05 +0530, Dhaval Giani wrote:
> Subject: sched: fully revert load_balance_monitor()
> 
> The following commit causes a number of serious regressions:
> 
>   commit 6b2d7700266b9402e12824e11e0099ae6a4a6a79
>   Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
>   Date:   Fri Jan 25 21:08:00 2008 +0100
>   sched: group scheduler, fix fairness of cpu bandwidth allocation for task groups
> 
> Namely:
>  - very frequent wakeups on SMP, reported by PowerTop users.
>  - cacheline trashing on (large) SMP
>  - some latencies larger than 500ms
> 
> While there is a mergeable patch to fix the latter, the former issues
> are IMHO not fixable in a manner suitable for .25 (we're at -rc3 now).
> Hence I propose to revert this patch and try again for .26.

I was just about to complain about the frequent wakeups caused by the
original patch.
It's responsible of 70% of wakeups on an otherwise idle system on s390.

Thanks :)

  reply	other threads:[~2008-02-25 15:53 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-25 12:22 [PATCH] sched: revert load_balance_monitor() Peter Zijlstra
2008-02-25 14:29 ` Mike Galbraith
2008-02-25 14:35   ` Dhaval Giani
2008-02-25 14:37     ` Mike Galbraith
2008-02-28 13:26       ` Ingo Molnar
2008-02-28 16:13         ` Mike Galbraith
2008-02-29  7:11           ` Mike Galbraith
2008-02-25 15:28     ` Peter Zijlstra
2008-02-25 15:53       ` Heiko Carstens [this message]
2008-02-25 16:01       ` Srivatsa Vaddagiri
2008-02-25 16:34         ` Peter Zijlstra

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