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 13:31:27 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>,
        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 Mon, Aug 03, 2020 at 01:00:12PM +0900, Namhyung Kim wrote:
> 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.

I wanted to show in changelog that the timestamps match
for both script and data convert tools

jirka

> 
> 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(-)
>