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

[Jiri Olsa <jolsa@redhat.com>]

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@kernel.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(-)
>