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;
From:   Changbin Du <changbin.du@gmail.com>
To:     Jiri Olsa <jolsa@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel@vger.kernel.org, Changbin Du <changbin.du@gmail.com>
Subject: [PATCH v2 07/15] perf ftrace: show trace column header
Date:   Sat, 27 Jun 2020 21:36:46 +0800
Message-Id: <20200627133654.64863-8-changbin.du@gmail.com>
In-Reply-To: <20200627133654.64863-1-changbin.du@gmail.com>
References: <20200627133654.64863-1-changbin.du@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

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