Re: [james-xen@dingwall.me.uk: [Xen-users] Xen 4.2.0 - CPU Frequency Scaling]

[James Dingwall <james@dingwall.me.uk>]

On Tue, Oct 02, 2012 at 03:08:39PM -0400, Konrad Rzeszutek Wilk wrote:
> >>
> >> What exactly are you trying to manage? As in what are you doing?
> >
> > What I was trying to achieve was 2 vcpus assigned and pinned to dom0 with
> > the remaining available for domUs.  I wanted to set the scaling governor as
> > performance for the dom0 vcpus and ondemand for domUs.
> >
> > It was an obvious test to change dom0_max_vcpus and I should have done it
> > before. On removing the parameter so that all cpus were seen in dom0 I could
> > control the power state of them all independently.  Reinstating the
> > parameter with value of n showed that cpu 1 - (n-1) could be controlled
> > independently while cpus 0 and n-11 were grouped together.
> 
> And this behavior existed with the old kernel? Or was this something
> you were trying to do now?

I seem to recall that with the old xen-sources kernel that this wasn't a 
problem as I had an init script which set the cpu frequency governors as 
I wanted them.  However once mainline got dom0 pvops I jumped to that 
and made do without that particular feature.  Once xen-acpi-processor 
was added then I noticed this behaviour.  It is possible that during 
that time I added the dom0_max_vcpus parameter and so I'm not comparing 
exactly the same configuration.  I'll poke around to see if I can find 
an old xen kernel which I can test with.

Thanks,
JAmes