Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200627133654.64863-1-changbin.du@gmail.com> <20200627133654.64863-8-changbin.du@gmail.com>
In-Reply-To: <20200627133654.64863-8-changbin.du@gmail.com>
From:   Namhyung Kim <namhyung@kernel.org>
Date:   Fri, 3 Jul 2020 15:20:15 +0900
Message-ID: <CAM9d7cgSniMTtFY4Mn9=M_C15cQSk4=YtaqZvAzj53brqed3hw@mail.gmail.com>
Subject: Re: [PATCH v2 07/15] perf ftrace: show trace column header
To:     Changbin Du <changbin.du@gmail.com>
Cc:     Jiri Olsa <jolsa@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sat, Jun 27, 2020 at 10:38 PM Changbin Du <changbin.du@gmail.com> 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@gmail.com>
> ---
>  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
>