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Date: Wed, 14 Mar 2007 12:47:58 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Rik van Riel <riel@redhat.com>
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       cpufreq@lists.linux.org.uk,
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Subject: Re: Stolen and degraded time and schedulers
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Rik van Riel wrote:
> Jeremy Fitzhardinge wrote:
>
>> It doesn't matter why you didn't get the time; 
>
> Oh, but it does.

I meant specifically from a scheduling perspective.

> System administrators can use steal time the same way they
> use iowait time: to spot bottlenecks on their systems.
>
> If you have a lot of iowait time, you know you want either
> faster IO or more memory.
>
> If you have a lot of steal time, you know you need to spread
> your virtual machines over more CPUs.
>
> Steal time allows you to see the difference between a busy
> system and an overloaded system.

Sure, the various accounting tools can go into as much detail as you
want.  I just added stolen time accounting to the xen-pv_ops patchset
which is equivalent to the xen-unstable stolen time accounting.  Is that
sufficient for these purposes?

    J