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

Peter Zijlstra
2012-06-07T10:45:44Z

On Thu, 2012-06-07 at 12:35 +0200, Stephane Eranian wrote:
> > This will only warn about the PEBS issue once you try and use a PEBS
> > counter. Shouldn't we do this on boot? IOW. put check_pebs_quirks()
> > inside the existing quirk code instead of here?
> >
> 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..?

> The other thing is that as it is now, if you
> get an error, you check dmesg and it's obvious what is wrong. With
> the boot warning, you'd have to look back all the way to the early boot
> messages. Whatever you prefer, I am fine.

We could do both I guess. But the event creation one needs a rate
limiter.