Date: Tue, 21 Mar 2006 18:50:04 +0100
From: Willy Tarreau <willy@w.ods.org>
To: Con Kolivas <kernel@kolivas.org>
Cc: Mike Galbraith <efault@gmx.de>, Ingo Molnar <mingo@elte.hu>,
       lkml <linux-kernel@vger.kernel.org>, Andrew Morton <akpm@osdl.org>,
       bugsplatter@gmail.com
Subject: Re: interactive task starvation
Message-ID: <20060321175004.GA27303@w.ods.org>
References: <200603090036.49915.kernel@kolivas.org> <1142949690.7807.80.camel@homer> <200603220117.54822.kernel@kolivas.org> <200603220220.11368.kernel@kolivas.org>
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On Wed, Mar 22, 2006 at 02:20:10AM +1100, Con Kolivas wrote:
> On Wednesday 22 March 2006 01:17, Con Kolivas wrote:
> > I actually believe the same effect can be had by a tiny 
> > modification to enable/disable the estimator anyway.
> 
> Just for argument's sake it would look something like this.
> 
> Cheers,
> Con
> ---
> Add sysctl to enable/disable cpu scheduer interactivity estimator

At least, in May 2005, the equivalent of this patch I tested on
2.6.11.7 considerably improved responsiveness, but there was still
this very annoying slowdown when the load increased. vmstat delays
increased by one second every 10 processes. I retried again around
2.6.14 a few months ago, and it was the same. Perhaps Mike's code
and other changes in 2.6-mm really fix the initial problem (array
switching ?) and then only the interactivity boost is causing the
remaining trouble ?

Cheers,
Willy

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