linux-kernel - Re: [PATCH V2 2/2] perf tools: always set no branch for dummy event in PT

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Date:   Mon, 3 Jul 2017 13:59:22 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     kan.liang@...el.com, linux-kernel@...r.kernel.org,
        mingo@...hat.com, peterz@...radead.org, adrian.hunter@...el.com,
        alexander.shishkin@...ux.intel.com, ak@...ux.intel.com
Subject: Re: [PATCH V2 2/2] perf tools: always set no branch for dummy event
 in PT

Em Mon, Jul 03, 2017 at 09:58:32AM +0200, Jiri Olsa escreveu:
> On Fri, Jun 30, 2017 at 10:16:56AM -0400, kan.liang@...el.com wrote:
> > From: Kan Liang <kan.liang@...el.com>
> > 
> > An earlier kernel patch allowed enabling PT and LBR at the same time on
> > Goldmont.
> > 
> > commit ccbebba4c6bf ("perf/x86/intel/pt: Bypass PT vs. LBR exclusivity
> > if the core supports it")
> > 
> > However, users still cannot use Intel PT and LBRs simultaneously.
> >  $ sudo perf record -e cycles,intel_pt//u -b  -- sleep 1
> >  Error:
> >  PMU Hardware doesn't support sampling/overflow-interrupts.
> > 
> > PT implicitly adds dummy event in perf tool. dummy event is software
> > event which doesn't support LBR.
> > 
> > Always setting no branch for dummy event in Intel PT.
> > 
> > Signed-off-by: Kan Liang <kan.liang@...el.com>
> 
> for the patchset:
> 
> Acked-by: Jiri Olsa <jolsa@...nel.org>

Thanks, applied.

- Arnaldo