Re: 2.6.16-rc5 perfmon2 new code base + libpfm with Montecito support

From: Stephane Eranian
Date: Wed Mar 08 2006 - 16:23:54 EST


Will,

On Wed, Mar 08, 2006 at 03:40:16PM -0500, William Cohen wrote:
> >
> >I have released another version of the perfmon new base package.
> >This release is relative to 2.6.16-rc5
>
> Hello Stephane,
>
> Is there any thoughts on how perfmon2 is going to work with xen enabled
> kernels or processors that support virtualization?
>

AFAIK, there is currently no Xen support for PMU on any platforms. By "support"
I mean suport for guests using the PMU. As such, I do not think this works.
I am planning on looking at this next because this is becoming a pressing matter
and not just on IA-64.

My first goal is to ensure that a guest using perfmon2 works once it is virtualized.
That implies that the Xen VMM does save/restore PMU state on guest switch. That's a bare
minimum.

As for HW virutlization support, I think it helps a little bit but there still needs to
be some additional code in the VMM to make this work correctly. This is also something
I want to look at.

--
-Stephane
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