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

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Message-ID: <37D7C6CF3E00A74B8858931C1DB2F077537141A7@SHSMSX103.ccr.corp.intel.com>
Date:   Thu, 29 Jun 2017 15:50:29 +0000
From:   "Liang, Kan" <kan.liang@...el.com>
To:     Jiri Olsa <jolsa@...hat.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 03:31:45PM +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.

Thanks,
Kan