[tip:perf/core] perf top: Fix annoying fallback message on older kernels

[tip-bot for Kan Liang]

Commit-ID:  853745f5e6d95faaae6381c9a01dbd43de992fb3
Gitweb:     https://git.kernel.org/tip/853745f5e6d95faaae6381c9a01dbd43de992fb3
Author:     Kan Liang <Kan.liang@xxxxxxxxx>
AuthorDate: Mon, 26 Feb 2018 10:17:10 -0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 26 Feb 2018 16:04:08 -0300

perf top: Fix annoying fallback message on older kernels

On older (e.g. v4.4) kernels, an annoying fallback message can be
observed in 'perf top':

	ââWarning:âââââââââââââââââââââââ
	âfall back to non-overwrite modeâ
	â                               â
	â                               â
	âPress any key...               â
	âââââââââââââââââââââââââââââââââ

The 'perf top' utility has been changed to overwrite mode since commit
ebebbf082357 ("perf top: Switch default mode to overwrite mode").

For older kernels which don't have overwrite mode support, 'perf top'
will fall back to non-overwrite mode and print out the fallback message
using ui__warning(), which needs user's input to close.

The fallback message is not critical for end users. Turning it to debug
message which is printed when running with -vv.

Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Link: http://lkml.kernel.org/r/1519669030-176549-1-git-send-email-kan.liang@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-top.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index b7c823ba8374..35ac016fcb98 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -991,7 +991,7 @@ static int perf_top_overwrite_fallback(struct perf_top *top,
 	evlist__for_each_entry(evlist, counter)
 		counter->attr.write_backward = false;
 	opts->overwrite = false;
-	ui__warning("fall back to non-overwrite mode\n");
+	pr_debug2("fall back to non-overwrite mode\n");
 	return 1;
 }