Re: [PATCH 1/3] perf tools: Fix period/freq terms setup

From: Jiri Olsa
Date: Mon Feb 05 2018 - 10:17:40 EST


On Fri, Feb 02, 2018 at 01:04:34PM -0800, Stephane Eranian wrote:
> On Fri, Feb 2, 2018 at 12:40 PM, Arnaldo Carvalho de Melo
> <acme@xxxxxxxxxx> wrote:
> > Em Fri, Feb 02, 2018 at 05:28:49PM -0300, Arnaldo Carvalho de Melo escreveu:
> >> Em Fri, Feb 02, 2018 at 10:45:46AM -0800, Stephane Eranian escreveu:
> >> > Otherwise, I tested what you have written so far and it works.
> >
> >> So I take that as a Tested-by: Stephane and will apply the patches, Jiri
> >> can continue working on these other aspects, right?
> >
> > I also added this for the casual reader to get up to speed more quickly,
> > please check that it makes sense.
> >
> > Committer note:
> >
> > When we use -c or a period=N term in the event definition, then we don't
> > need to ask the kernel, via perf_event_attr.sample_type |=
> > PERF_SAMPLE_PERIOD, to put the event period in each sample, as we know
> > it already, it is in perf_event_attr.sample_period.
> >
> Not quite. It depends on how each event is setup. I can mix & match period
> and frequency. The PERF_SAMPLE_PERIOD can be dropped only if all the
> events use a fixed period either via period=N or -c.

I think you can have both period and freq based event in one session
if that's your concern..? what would be the problem?

jirka

> I hope that perf report can deal with config mixing period and fixed
> mode correctly.