linux-kernel - Re: [PATCH] perf tools: set no branch type for dummy event in PT

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Date:   Fri, 30 Jun 2017 09:06:24 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     "Liang, Kan" <kan.liang@...el.com>
Cc:     "acme@...nel.org" <acme@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "Hunter, Adrian" <adrian.hunter@...el.com>,
        "alexander.shishkin@...ux.intel.com" 
        <alexander.shishkin@...ux.intel.com>,
        "ak@...ux.intel.com" <ak@...ux.intel.com>
Subject: Re: [PATCH] perf tools: set no branch type for dummy event in PT

On Thu, Jun 29, 2017 at 03:50:29PM +0000, Liang, Kan wrote:
> 
> 
> > 
> > On Thu, Jun 29, 2017 at 03:31:45PM +0000, Liang, Kan wrote:
> > 
> > SNIP
> > 
> > > > >  static int intel_pt_recording_options(struct auxtrace_record *itr,
> > > > >  				      struct perf_evlist *evlist,
> > > > >  				      struct record_opts *opts) @@ -701,6
> > +717,8 @@ static
> > > > > int intel_pt_recording_options(struct
> > > > auxtrace_record *itr,
> > > > >  				perf_evsel__set_sample_bit(switch_evsel,
> > > > TIME);
> > > > >  				perf_evsel__set_sample_bit(switch_evsel,
> > > > CPU);
> > > > >
> > > > > +				add_no_lbr_config_term(&switch_evsel-
> > > > >config_terms);
> > > > > +
> > > >
> > > > hum, why can't you change the sample bit directly? with:
> > > >
> > > > 			perf_evsel__reset_sample_bit(switch_evsel,
> > > > BRANCH_STACK);
> > >
> > > It will be overwrite in perf_evsel__config.
> > >
> > 
> > where? you set the evsel->no_aux_samples
> 
> Yes for switch_evsel, but no for tracking_evsel.
> 
> If it's only for switch_evsel, yes, we can change the sample bit directly.
> But I think we should use the same method for both of them.


we could set the no_aux_samples for the tracking_evsel as well

jirka