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 09:58:32 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     kan.liang@...el.com
Cc:     acme@...nel.org, 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

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,
jirka