Re: [PATCH] Enhance perf to collect KVM guest os statistics from host side

Peter Zijlstra
2010-03-23T15:23:01Z

On Tue, 2010-03-23 at 11:10 -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Mar 23, 2010 at 02:49:01PM +0100, Andi Kleen escreveu:
> > Soeren Sandmann <sandmann@daimi.au.dk> writes:
> > > To fix that problem, it seems like we need some way to have python
> > > export what is going on. Maybe the same mechanism could be used to
> > > both access what is going on in qemu and python.
> >
> > oprofile already has an interface to let JITs export
> > information about the JITed code. C Python is not a JIT,
> > but presumably one of the python JITs could do it.
> >
> > http://oprofile.sourceforge.net/doc/devel/index.html
> >
> > I know it's not envogue anymore and you won't be a approved
> > cool kid if you do, but you could just use oprofile?
>
> perf also has supports for this and Pekka Enberg's jato uses it:
>
> http://penberg.blogspot.com/2009/06/jato-has-profiler.html

Right, we need to move that into a library though (always meant to do
that, never got around to doing it).

That way the app can link against a dso with weak empty stubs and have
perf record LD_PRELOAD a version that has a suitable implementation.

That all has the advantage of not exposing the actual interface like we
do now.