[tip:perf/core] perf top: Tell the user how to unfreeze events after pressing 'f'

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  ae3b6ab603bce6a74ca089f7a944196863166a52
Gitweb:     http://git.kernel.org/tip/ae3b6ab603bce6a74ca089f7a944196863166a52
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Fri, 19 Jun 2015 17:35:25 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 19 Jun 2015 18:13:59 -0300

perf top: Tell the user how to unfreeze events after pressing 'f'

When the user presses 'f' to disable events the visual cues are, well,
the percentages not changing and the number of events freezing.

Be more explicit by changing the help line at the bottom of the screen
to show the following messages when 'f' is pressed:

  "Press 'f' again to re-enable the events"

And then, when 'f' is pressed again:

  "Press 'f' to disable the events or 'h'

Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-uhiswg9a9rxm5gxg7ptjskjn@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-top.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index ccf569a..70a9505 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -599,7 +599,13 @@ static void *display_thread_tui(void *arg)
 		 * No need to refresh, resort/decay histogram entries
 		 * if we are not collecting samples:
 		 */
-		hbt.refresh = top->evlist->enabled ? top->delay_secs : 0;
+		if (top->evlist->enabled) {
+			hbt.refresh = top->delay_secs;
+			help = "Press 'f' to disable the events or 'h' to see other hotkeys";
+		} else {
+			help = "Press 'f' again to re-enable the events";
+			hbt.refresh = 0;
+		}
 	}
 
 	done = 1;
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