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Subject[tip:perf/urgent] perf top: Fix annoying fallback message on older kernels
Commit-ID:  626af862da9c650e80bdea44684be9334f8eb75b
Author: Kan Liang <>
AuthorDate: Mon, 26 Feb 2018 10:17:10 -0800
Committer: Arnaldo Carvalho de Melo <>
CommitDate: Mon, 5 Mar 2018 11:48:56 -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':

│fall back to non-overwrite mode│
│ │
│ │
│Press any key... │

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 <>
Signed-off-by: Kan Liang <>
Cc: Kan Liang <>
Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Signed-off-by: Arnaldo Carvalho de Melo <>
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;

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