Message-ID: <4AAE5D60.2080703@nortel.com>
Date: Mon, 14 Sep 2009 09:12:32 -0600
From: "Chris Friesen" <cfriesen@nortel.com>
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To: Mike Galbraith <efault@gmx.de>
CC: pavel@pavlinux.ru, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: INGO Why you remove  set_user_nice() from kernel/kthread.c
References: <200909141742.45487.pavel@pavlinux.ru> <1252937140.6500.11.camel@marge.simson.net>
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On 09/14/2009 08:05 AM, Mike Galbraith wrote:
> If you're asking Ingo a question, maybe a CC is in order.
> 
> On Mon, 2009-09-14 at 17:42 +0400, Pavel Vasilyev wrote:
>>
>> Next patсh -  
>> http://www.kernel.org/diff/diffview.cgi?file=%2Fpub%2Flinux%2Fkernel%2F%2Fv2.6%2Fsnapshots%2Fpatch-2.6.31-git2.bz2;z=548
>>
>> This patch defines the core processes that are working with nice leve equal to 
>> zero , as in the BFS. :)
>>
>> Why?
> 
> I did that, not Ingo, and did so because with kthreads that use
> diddly-spit CPU (every one I see), it's just a waste of math.  What
> kthreads are you seeing using so much CPU that their weight is a factor?
> They _should_ be able to preempt and get their work done just fine
> without a boost.

Under heavy network load ksoftirqd can use significant amounts of cpu.

Chris
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