After this patch, 'perf data convert' convert comm events to output CTF
stream.

Result:

  # perf record -a sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.378 MB perf.data (73 samples)  ]

  # perf data convert --to-ctf ./out.ctf
  [ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ]
  [ perf data convert: Converted and wrote 0.003 MB (73 samples) ]

  # babeltrace --clock-seconds ./out.ctf/
  [10627.402515791] (+?.?????????) cycles:ppp: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF81065AF4, perf_tid = 0, perf_pid = 0, perf_period = 1 }
  [10627.402518972] (+0.000003181) cycles:ppp: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF81065AF4, perf_tid = 0, perf_pid = 0, perf_period = 1 }
  ...    // only sample event is converted

  # perf data convert --all --to-ctf ./out.ctf
  [ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ]
  [ perf data convert: Converted and wrote 0.023 MB (73 samples, 384 non-samples) ]

  # babeltrace --clock-seconds ./out.ctf/
  [  0.000000000] (+?.?????????) perf_comm: { cpu_id = 0 }, { pid = 1, tid = 1, comm = "init" }
  [  0.000000000] (+0.000000000) perf_comm: { cpu_id = 0 }, { pid = 2, tid = 2, comm = "kthreadd" }
  [  0.000000000] (+0.000000000) perf_comm: { cpu_id = 0 }, { pid = 3, tid = 3, comm = "ksoftirqd/0" }
  ...    // comm events are converted
  [10627.402515791] (+10627.402515791) cycles:ppp: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF81065AF4, perf_tid = 0, perf_pid = 0, perf_period = 1 }
  [10627.402518972] (+0.000003181) cycles:ppp: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF81065AF4, perf_tid = 0, perf_pid = 0, perf_period = 1 }
  ...    // samples are also converted

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1466767332-114472-7-git-send-email-wangnan0@huawei.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>