[tip:perf/core] perf ftrace: Use pager for displaying result

[tip-bot for Namhyung Kim]

Commit-ID:  583359646fde8526ea9456618cc24dc359b34094
Gitweb:     http://git.kernel.org/tip/583359646fde8526ea9456618cc24dc359b34094
Author:     Namhyung Kim <namhyung@xxxxxxxxxx>
AuthorDate: Fri, 24 Feb 2017 10:12:51 +0900
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 3 Mar 2017 19:07:17 -0300

perf ftrace: Use pager for displaying result

It's convenient to use the pager when seeing many lines of result.

Note that setup_pager() should be called after perf_evlist__prepare_workload()
since they can interfere each other regarding shared stdio streams.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: kernel-team@xxxxxxx
Link: http://lkml.kernel.org/r/20170224011251.14946-4-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 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 d5b566e..6087295 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -195,6 +195,7 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 	signal(SIGINT, sig_handler);
 	signal(SIGUSR1, sig_handler);
 	signal(SIGCHLD, sig_handler);
+	signal(SIGPIPE, sig_handler);
 
 	if (reset_tracing_files(ftrace) < 0)
 		goto out;
@@ -247,6 +248,8 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 		goto out_close_fd;
 	}
 
+	setup_pager();
+
 	perf_evlist__start_workload(ftrace->evlist);
 
 	while (!done) {