linux-kernel - Re: [PATCH 4/6] perf tools: Add support to store time of day in CTF data conversion

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Date:   Mon, 3 Aug 2020 13:00:12 +0900
From:   Namhyung Kim <namhyung@...nel.org>
To:     Jiri Olsa <jolsa@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Michael Petlan <mpetlan@...hat.com>,
        Ian Rogers <irogers@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        David Ahern <dsahern@...il.com>,
        Geneviève Bastien <gbastien@...satic.net>,
        Wang Nan <wangnan0@...wei.com>,
        Jeremie Galarneau <jgalar@...icios.com>
Subject: Re: [PATCH 4/6] perf tools: Add support to store time of day in CTF
 data conversion

On Thu, Jul 30, 2020 at 11:39:48PM +0200, Jiri Olsa wrote:
> Adding support to convert and store time of day in CTF
> data conversion for 'perf data convert' subcommand.
> 
> The perf.data used for conversion needs to have clock data
> information - must be recorded with -k/--clockid option).
> 
> New --tod option is added to 'perf data convert' subcommand
> to convert data with timestamps converted to wall clock time.
> 
> Record data with clockid set:
>   # perf record -k CLOCK_MONOTONIC kill
>   kill: not enough arguments
>   [ perf record: Woken up 1 times to write data ]
>   [ perf record: Captured and wrote 0.033 MB perf.data (8 samples) ]
> 
> Convert data with TOD timestamps:
>   # perf data convert --tod --to-ctf ./ctf
>   [ perf data convert: Converted 'perf.data' into CTF data './ctf' ]
>   [ perf data convert: Converted and wrote 0.000 MB (8 samples) ]
> 
> Display data in perf script:
>   # perf script -F+tod --ns
>             perf 262150 2020-07-13 18:38:50.097678523 153633.958246159:          1 cycles: ...
>             perf 262150 2020-07-13 18:38:50.097682941 153633.958250577:          1 cycles: ...
>             perf 262150 2020-07-13 18:38:50.097684997 153633.958252633:          7 cycles: ...
>   ...

I believe this belongs to a later patch.

Thanks
Namhyung

> 
> Display data in babeltrace:
>   # babeltrace --clock-date  ./ctf
>   [2020-07-13 18:38:50.097678523] (+?.?????????) cycles: { cpu_id = 0 }, { perf_ip = 0xFFF ...
>   [2020-07-13 18:38:50.097682941] (+0.000004418) cycles: { cpu_id = 0 }, { perf_ip = 0xFFF ...
>   [2020-07-13 18:38:50.097684997] (+0.000002056) cycles: { cpu_id = 0 }, { perf_ip = 0xFFF ...
>   ...
> 
> It's available only for recording with clockid specified,
> because it's the only case where we can get reference time
> to wallclock time. It's can't do that with perf clock yet.
> 
> Error is display if you want to use --tod on data without
> clockid specified:
> 
>   # perf data convert --tod --to-ctf ./ctf
>   Can't provide --tod time, missing clock data. Please record with -k/--clockid option.
>   Failed to setup CTF writer.
>   Error during conversion setup.
> 
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/perf/Documentation/perf-data.txt |  3 ++
>  tools/perf/builtin-data.c              |  1 +
>  tools/perf/util/data-convert-bt.c      | 56 +++++++++++++++++---------
>  tools/perf/util/data-convert.h         |  1 +
>  4 files changed, 41 insertions(+), 20 deletions(-)