Re: [PATCH] perf/x86: Reject non sampling events with precise_ip

From: Vince Weaver
Date: Tue Jan 03 2017 - 17:06:45 EST


On Tue, 3 Jan 2017, Jiri Olsa wrote:
> On Tue, Jan 03, 2017 at 10:40:59AM +0100, Peter Zijlstra wrote:
> >
> > I think we should reject non sampling pebs events, as you say they make
> > no sense what so ever.
>
> ook, attached
>

you can use the PEBS events to gather aggregate stats though and they
seem roughly right. Are they truly meaningless?

I had misremembered that they might not have the determinism problems of
regular events (turns out that's wrong). They oddly seem to be worse in
some limited tests I did.

So I guess nothing will be lost if they're disabled.

Vince