[PATCH v8 05/18] perf ftrace: show trace column header

From: Changbin Du
Date: Fri Aug 07 2020 - 22:32:35 EST


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@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 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