Subject: Re: 2.6.24-git4+ regression
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Lukas Hejtmanek <xhejtman@ics.muni.cz>
Cc: Ingo Molnar <mingo@elte.hu>, mingo@redhat.com,
       linux-kernel@vger.kernel.org
In-Reply-To: <20080204143622.GC4329@ics.muni.cz>
References: <20080130135609.GA5100@ics.muni.cz>
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Date: Mon, 04 Feb 2008 15:45:10 +0100
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On Mon, 2008-02-04 at 15:36 +0100, Lukas Hejtmanek wrote:
> On Mon, Feb 04, 2008 at 12:36:36PM +0100, Peter Zijlstra wrote:
> > I can't reproduce this with a pure cpu load. I started 10 
> >   while :; do :; done &
> > instances and aside from slowing down, nothing bad happened.
> 
> yes, while true; do true; does nothing wrong. But running make -j2 in kernel
> sources or mesa sources is catastrophic.
>  
> > May I suggest you try latency top to see if there is something in your
> > build scenario that generates horrible latencies (some IO path or
> > whatnot).
> 
> see my previous mail to Ingo (you were Cc.), latency top says that Xorg and
> gnome-terminal suffers 300+ms latency in scheduler: waiting for cpu.

what happens when you turn CONFIG_FAIR_GROUP_SCHED off?

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