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To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: John Stoffel <john@stoffel.org>,
       kvm-devel <kvm-devel@lists.sourceforge.net>,
       Laurent Vivier <Laurent.Vivier@bull.net>,
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From: laurent.vivier@bull.net
Subject: =?iso-8859-1?Q?R=E9f=2E_=3A_Re=3A_[PATCH_0=2F4]_Virtual_Machine_Time?=
 Accounting
Date: Mon, 20 Aug 2007 19:54:52 +0200
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> Laurent Vivier wrote:
> functionnalities:
>
> > - allow to measure time spent by a CPU in a virtual CPU.
> > - allow to display in /proc/state this value by CPU
> > - allow to display in /proc/<pid>/state this value by process
> > - allow KVM to use these 3 previous functionnalities
> >
>
> So, currently time spent in a kvm guest is accumulated as qemu-kvm
> usertime, right?  Given that qemu knows when its running in qemu vs

No, it is accumulated as kvm system time.

> guest context, couldn't it provide the breakdown between user and guest
> time (ditto lguest)?

by doing this at kernel level, we can:
- measure exactly the guest time,
- move this part of system time to user time (as you think it should be
user time),
- have consistency between system, user and guest time,
- report values in /proc/state and /proc/<pid>/state, at system wide level

I'm not sure we can measure the guest time at the qemu user level.

Perhaps Rusty can say what he thinks about this ?

Regards,
Laurent


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