perf record: Clarify help for --switch-output

The help description for --switch-output looks like there are multiple
comma separated fields. But it's actually a choice of different options.
Make it clear and less confusing.

Before:

  % perf record -h
  ...
          --switch-output[=<signal,size,time>]
                            Switch output when receive SIGUSR2 or cross size,time threshold

After:

  % perf record -h
  ...

          --switch-output[=<signal or size[BKMG] or time[smhd]>]
                            Switch output when receiving SIGUSR2 (signal) or cross a size or time threshold

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
LPU-Reference: 20190314225002.30108-4-andi@firstfloor.org
Link: https://lkml.kernel.org/n/tip-9yecyuha04nyg8toyd1b2pgi@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 02d7c40b2d106f0b37ddd07f979f68b3a9532650..e7144a1c1c8226d4bb49f06d0ebb3d90cae51cff 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1989,8 +1989,8 @@ static struct option __record_options[] = {
        OPT_BOOLEAN(0, "timestamp-boundary", &record.timestamp_boundary,
                    "Record timestamp boundary (time of first/last samples)"),
        OPT_STRING_OPTARG_SET(0, "switch-output", &record.switch_output.str,
-                         &record.switch_output.set, "signal,size,time",
-                         "Switch output when receive SIGUSR2 or cross size,time threshold",
+                         &record.switch_output.set, "signal or size[BKMG] or time[smhd]",
+                         "Switch output when receiving SIGUSR2 (signal) or cross a size or time threshold",
                          "signal"),
        OPT_INTEGER(0, "switch-max-files", &record.switch_output.num_files,
                   "Limit number of switch output generated files"),