linux-kernel - Re: [PATCH v2 2/4] perf arm-spe: Update --switch-events docs in perf-record

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Date:   Thu, 11 Nov 2021 15:18:15 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     German Gomez <german.gomez@....com>
Cc:     linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        acme@...nel.org, Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/4] perf arm-spe: Update --switch-events docs in
 perf-record

On Tue, Nov 09, 2021 at 11:50:18AM +0000, German Gomez wrote:
> Update perf-record docs and Arm SPE recording options so that they are
> consistent. This includes supporting the --no-switch-events flag in Arm
> SPE as well.
> 
> Signed-off-by: German Gomez <german.gomez@....com>

Reviewed-by: Leo Yan <leo.yan@...aro.org>

> ---
>  tools/perf/Documentation/perf-record.txt | 2 +-
>  tools/perf/arch/arm64/util/arm-spe.c     | 4 +++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index 2d7df8703..3cf7bac67 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -469,7 +469,7 @@ This option sets the time out limit. The default value is 500 ms.
>  
>  --switch-events::
>  Record context switch events i.e. events of type PERF_RECORD_SWITCH or
> -PERF_RECORD_SWITCH_CPU_WIDE. In some cases (e.g. Intel PT or CoreSight)
> +PERF_RECORD_SWITCH_CPU_WIDE. In some cases (e.g. Intel PT, CoreSight or Arm SPE)
>  switch events will be enabled automatically, which can be suppressed by
>  by the option --no-switch-events.
>  
> diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> index 58ba8d15c..725a06cd2 100644
> --- a/tools/perf/arch/arm64/util/arm-spe.c
> +++ b/tools/perf/arch/arm64/util/arm-spe.c
> @@ -169,8 +169,10 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
>  	if (!perf_cpu_map__empty(cpus)) {
>  		evsel__set_sample_bit(tracking_evsel, TIME);
>  		evsel__set_sample_bit(tracking_evsel, CPU);
> +
>  		/* also track task context switch */
> -		tracking_evsel->core.attr.context_switch = 1;
> +		if (!record_opts__no_switch_events(opts))
> +			tracking_evsel->core.attr.context_switch = 1;
>  	}
>  
>  	return 0;
> -- 
> 2.25.1
>