Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge

Ingo Molnar
2012-06-08T09:35:21Z

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, 2012-06-07 at 12:48 +0200, Stephane Eranian wrote:
> > >> The warning could also be done on boot. But the check has to be done
> > >> when the event is created.
> > >
> > > Is this because of the ucode loader not having done its thing yet etc..?
>
> Ah, its because you can update ucode at runtime of course.
>
> A quick look at the ucode loader doesn't show it having a
> notifier either, so then yeah we need to check on every event
> creation :/
>
> Or we could put a hook in the ucode loader.

I'd really suggest the latter - I doubt this will be our only
ucode dependent quirk, going forward ...

Thanks,

Ingo