Adad 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: ...
...

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
Cc: Alexander Shishkin
Cc: Andi Kleen
Cc: David Ahern
Cc: Geneviève Bastien
Cc: Ian Rogers
Cc: Jeremie Galarneau
Cc: Michael Petlan
Cc: Namhyung Kim
Cc: Peter Zijlstra
Cc: Wang Nan
Link: http://lore.kernel.org/lkml/20200805093444.314999-6-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo