[tip:perf/core] perf c2c: Fix display bug when using pipe

[tip-bot for Namhyung Kim]

Commit-ID:  1936feae54a6724a27a6ca1b948fd0e80371f7b0
Gitweb:     http://git.kernel.org/tip/1936feae54a6724a27a6ca1b948fd0e80371f7b0
Author:     Namhyung Kim <namhyung@xxxxxxxxxx>
AuthorDate: Wed, 8 Mar 2017 00:08:33 +0900
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 7 Mar 2017 12:48:46 -0300

perf c2c: Fix display bug when using pipe

Currently 'perf c2c report' determines display mode using the --stdio
option, but it could be a problem if stdout is not a tty since
setup_browser falls back to stdio in this case.

But perf c2c didn't know this and tried to use TUI browser anyway.  It
should check "use_browser" variable instead.

For example, the following command showed nothing and broke terminal
setting.  Now it's fixed..

  $ perf c2c report | head
  =================================================
              Trace Event Information
  =================================================
    Total records                     :        136
    Locked Load/Store Operations      :          6
    Load Operations                   :         62
    Loads - uncacheable               :          0
    Loads - IO                        :          1
    Loads - Miss                      :          7
    Loads - no mapping                :          2

Committer notes:

When trying it without a proper perf.data file it results in a stuck
terminal, just as Namhyung reported above:

  [acme@jouet ~]$ perf c2c report | head
  WARNING: no sample cpu value[acme@jouet ~]$

One has to kill it from some other xterm. Confirm that this patch fixes
it:

After:

  $ perf c2c report | head
  WARNING: no sample cpu value=================================================
              Trace Event Information
  =================================================
    Total records                     :         14
    Locked Load/Store Operations      :          0
    Load Operations                   :          0
    Loads - uncacheable               :          0
    Loads - IO                        :          0
    Loads - Miss                      :          0
    Loads - no mapping                :          0
  $

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: kernel-team@xxxxxxx
Link: http://lkml.kernel.org/r/20170307150851.22304-6-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-c2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 3fac30e..5cd6d7a 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -2334,7 +2334,7 @@ out:
 
 static void perf_c2c_display(struct perf_session *session)
 {
-	if (c2c.use_stdio)
+	if (use_browser == 0)
 		perf_c2c__hists_fprintf(stdout, session);
 	else
 		perf_c2c__hists_browse(&c2c.hists.hists);