[Novalug] Virtual box cpu usage
Jon LaBadie
novalugml@jgcomp.com
Sat Dec 13 08:59:34 EST 2008
On Fri, Dec 12, 2008 at 09:27:26AM -0500, The Doctor wrote:
> Jon LaBadie wrote:
> > Under Fedora 9 I have VirtualBox running
> > a winXP pro session. I have few bkg procs
> > running on winXP. If I'm not doing any
> > windows tasks the task manager shows V low
> > cpu usage. Yet in this "idle state", top on
> > Fedora 9 shows VBox is using 30-35% of one
> > core of my system.
> >
> > This is my first experience with VBox. Is
> > this type of idle cpu usage typical?
>
> It seems a little odd. I've been using VirtualBox for a couple of
> months to test it out, and I've noticed that it tends to bounce between
> 4% and 19% of CPU utilization if you let the guest OS run on its own
> (Windows XP SP2).
>
> How much RAM do you have in your box? How many CPUs, and of what kind?
> What revision of VirtualBox are you running?
>
> Jon LaBadie wrote:
>
> > System is dual core AMD 5600 with 4GB of RAM.
> > Running the PAE version of Fedora 9 so I see all 4GB.
> > VBox version is 2.06.
>
> <whistles>
>
> This is strange, indeed. I'm running VirtualBox v2.0.4 on a dual-core
> laptop (Intel T7500 (2.2 GHz)) with 2GB of RAM on top of Gentoo 2008.0
> (kernel revision 2.6.27.4).
>
Turns out it was an example of the Heisenberg uncertainty principle
(or Schrodinger's cat if you prefer :) where the experimental tools
were affecting the results.
My primary measurement tool was the graphical gnome-system-monitor.
Turns out this consumes substantial Xorg cpu cycles for its updates.
I compiled an alternative (sdtperfmeter and rstatd) from the
Solaris world and sure enough there is little total cpu usage
when both native Fedora and the virtual winXP are idle.
Jon
--
Jon H. LaBadie jon@jgcomp.com
JG Computing
12027 Creekbend Drive (703) 787-0884
Reston, VA 20194 (703) 787-0922 (fax)
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