Re: [PATCH v2 07/15] perf ftrace: show trace column header

[Namhyung Kim]

On Sat, Jun 27, 2020 at 10:38 PM Changbin Du <changbin.du@xxxxxxxxx> wrote:
>
> 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

You'd better indent the example output by 2 spaces to prevent
the # signs commented out.

Thanks
Namhyung


>
> Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
> ---
>  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 e45496012611..686d744d5025 100644
> --- a/tools/perf/builtin-ftrace.c
> +++ b/tools/perf/builtin-ftrace.c
> @@ -430,6 +430,9 @@ 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 (!ftrace->initial_delay) {
>                 if (write_tracing_file("tracing_on", "1") < 0) {
>                         pr_err("can't enable tracing\n");
> --
> 2.25.1
>