[PATCH] perf stat: Don't print bogus data when one event is requested

[PATCH] perf stat: Don't print bogus data when one event is requested

[Ramkumar Ramachandra]

When only the stalled-cycles-frontend event is requested:

  $ perf stat -e stalled-cycles-frontend -- git s
  ## acme...ram/acme

   Performance counter stats for 'git s':

         326,947,423      stalled-cycles-frontend   #    0.00% frontend cycles idle

         0.363599976 seconds time elapsed

The 0.00% frontend cycles idle comment in the output is totally bogus
and misleading. Omit printing it here, as well as in the
stalled-cycles-backend case.

Cc: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 tools/perf/builtin-stat.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 8b0e1c9..0bd98fa 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -797,14 +797,13 @@ static void print_stalled_cycles_frontend(int cpu,
 
 	total = avg_stats(&runtime_cycles_stats[cpu]);
 
-	if (total)
+	if (total) {
 		ratio = avg / total * 100.0;
-
-	color = get_ratio_color(GRC_STALLED_CYCLES_FE, ratio);
-
-	fprintf(output, " #  ");
-	color_fprintf(output, color, "%6.2f%%", ratio);
-	fprintf(output, " frontend cycles idle   ");
+		color = get_ratio_color(GRC_STALLED_CYCLES_FE, ratio);
+		fprintf(output, " #  ");
+		color_fprintf(output, color, "%6.2f%%", ratio);
+		fprintf(output, " frontend cycles idle   ");
+	}
 }
 
 static void print_stalled_cycles_backend(int cpu,
@@ -816,14 +815,13 @@ static void print_stalled_cycles_backend(int cpu,
 
 	total = avg_stats(&runtime_cycles_stats[cpu]);
 
-	if (total)
+	if (total) {
 		ratio = avg / total * 100.0;
-
-	color = get_ratio_color(GRC_STALLED_CYCLES_BE, ratio);
-
-	fprintf(output, " #  ");
-	color_fprintf(output, color, "%6.2f%%", ratio);
-	fprintf(output, " backend  cycles idle   ");
+		color = get_ratio_color(GRC_STALLED_CYCLES_BE, ratio);
+		fprintf(output, " #  ");
+		color_fprintf(output, color, "%6.2f%%", ratio);
+		fprintf(output, " backend  cycles idle   ");
+	}
 }
 
 static void print_branch_misses(int cpu,
-- 
1.9.0.431.g014438b

Re: [PATCH] perf stat: Don't print bogus data when one event is requested

[Jiri Olsa]

On Thu, Mar 27, 2014 at 06:20:59PM -0400, Ramkumar Ramachandra wrote:
> When only the stalled-cycles-frontend event is requested:
> 
>   $ perf stat -e stalled-cycles-frontend -- git s
>   ## acme...ram/acme
> 
>    Performance counter stats for 'git s':
> 
>          326,947,423      stalled-cycles-frontend   #    0.00% frontend cycles idle
> 
>          0.363599976 seconds time elapsed
> 
> The 0.00% frontend cycles idle comment in the output is totally bogus
> and misleading. Omit printing it here, as well as in the
> stalled-cycles-backend case.

hi,
I agree with the change, but the reason for 0% is not only that
'one' event was stated, but that 'cycles' event is missing in
measurement.

Please change your changelog accordingly, the change itself
looks ok.

thanks,
jirka