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RE: [Xen-devel] cpufreq status information

To: "Jan Beulich" <jbeulich@xxxxxxxxxx>, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>
Subject: RE: [Xen-devel] cpufreq status information
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Mon, 8 Sep 2008 22:57:37 +0800
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Thread-topic: [Xen-devel] cpufreq status information
>From: Jan Beulich [mailto:jbeulich@xxxxxxxxxx] 
>Sent: 2008年9月8日 22:31
>>>> Keir Fraser <keir.fraser@xxxxxxxxxxxxx> 08.09.08 16:00 >>>
>>After all, guest performance is at least as affected by CPU (and other
>>resources) contention from other guests as it is by power-management
>>governors in the hyeprvisor. Indeed, if the governors are 
>doing their job
>>right then guest performance should not be considerably 
>impacted by them
>>even in absolute terms.
>Right you say 'if' - what if not? How do I tell, especially 
>when I can't touch
>the system and easily put a patched hypervisor and/or kernel on. If we
>get a complaint from a customer that he thinks frequency 
>scaling doesn't
>do what it's expected to, we'll need to have a simple mechanism at hand
>to determine what's going on with his box.

Extend this complaint to the case, where a customer complains that he
thinks frequency scaling on (v)cpu 0 doesn't do what it's expected to, how
do you check what's going on if there's no fixed mapping between vcpu
and pcpu, and no tool talking to xen directly...


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