Re: [RFC][PATCH 0/3] perf support for amd guest/host-only bits

From: Ingo Molnar
Date: Tue May 10 2011 - 16:42:09 EST



* Roedel, Joerg <Joerg.Roedel@xxxxxxx> wrote:

> On Tue, May 10, 2011 at 11:21:32AM -0400, Ingo Molnar wrote:
> >
> > * Joerg Roedel <joerg.roedel@xxxxxxx> wrote:
> >
> > > So any feedback is greatly appreciated :-)
> >
> > it's nice to see this hw feature utilized :)
>
> Yeah, I planned to do this for some time now and finally found the time
> to do it :)
>
> >
> > > Diffstat:
> > >
> > > arch/x86/include/asm/perf_event.h | 3 +++
> > > arch/x86/kernel/cpu/perf_event_amd.c | 6 ++++++
> > > include/linux/perf_event.h | 5 ++++-
> > > kernel/perf_event.c | 4 ++++
> > > tools/perf/util/parse-events.c | 10 +++++++++-
> > > 5 files changed, 26 insertions(+), 2 deletions(-)
> >
> > I see you have not touched tools/perf/builtin-kvm.c - how does this feature
> > integrate with the features of 'perf kvm'? (are you using perf kvm by any
> > chance?)
>
> builtin-kvm looks like a wrapper for other perf-cmds which just sets up
> some additional state to tell the sub-cmds that guest-symbols need to be
> resolved and so on.
>
> Implementing this into the place where the other exclude-bits get set (which
> is in generic code) seemed like a good idea to me. Touching builtin-kvm was
> unnecessary for this.

ok, then let me put it in another way:

'perf kvm' is the tool that is making Linux instrumentation friendlier to KVM
developers. Can you think of ways to utilize this new feature there?

For example a new 'perf kvm stat' feature could pass the exclusion bits to perf
stat automatically. 'perf kvm record' could record on the guest only by
default.

Things like that.

Thanks,

Ingo
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