Em Sat, Aug 08, 2020 at 10:31:28AM +0800, Changbin Du escreveu:
> This makes perf-ftrace display column header before printing trace.
>
> $ sudo perf ftrace
> # tracer: function
> #
> # entries-in-buffer/entries-written: 0/0 #P:8
> #
> # TASK-PID CPU# TIMESTAMP FUNCTION
> # | | | | |
> <...>-9246 [006] 10726.262760: mutex_unlock <-rb_simple_write
> <...>-9246 [006] 10726.262764: __fsnotify_parent <-vfs_write
> <...>-9246 [006] 10726.262765: fsnotify <-vfs_write
> <...>-9246 [006] 10726.262766: __sb_end_write <-vfs_write
> <...>-9246 [006] 10726.262767: fpregs_assert_state_consistent
> <-do_syscall_64
We have:
# perf report -h header
Usage: perf report [<options>]
--header Show data header.
--header-only Show only data header.
#
So perhaps we should have those as well, in the 'ftrace' case one would
perhaps want to use --no-header, for instance, to do some scripting
parsing just the trace lines.
- Arnaldo
> Signed-off-by: Changbin Du <[email protected]>
> ---
> tools/perf/builtin-ftrace.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> index a3a4f4be9dde..39c694be2b71 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -435,6 +435,9 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int
> argc, const char **argv)
> fcntl(trace_fd, F_SETFL, O_NONBLOCK);
> pollfd.fd = trace_fd;
>
> + /* display column headers */
> + read_tracing_file_to_stdout("trace");
> +
> if (write_tracing_file("tracing_on", "1") < 0) {
> pr_err("can't enable tracing\n");
> goto out_close_fd;
> --
> 2.25.1
>
--
- Arnaldo
