Re: perf stat output

From: Lucas De Marchi
Date: Sun Nov 15 2009 - 09:05:06 EST


Ingo, following the tested patch you asked. It's a bit different of what you
sent because branch-misses is counted in another struct.


Lucas De Marchi

--
commit 70e98c814153f0026a683c5d19674ed8185d02fa
Author: Lucas De Marchi <lucas.de.marchi@xxxxxxxxx>
Date: Sun Nov 15 11:20:56 2009 -0200

Do not print ratio when task-clock event is not counted

The ratio between the number of events and the time elapsed makes sense only
if task-clock event is counted. Otherwise it will be simply a (confusing)

# 0.000 M/sec

This patch outputs the ratio only if task-clock event is counted. Some test
examples of before and after:

Before:

[lucas@skywalker linux.trees.git]$ sudo perf stat -e branch-misses -a -- sleep 1

Performance counter stats for 'sleep 1':

1367818 branch-misses # 0.000 M/sec

1.001494325 seconds time elapsed

After (without task-clock):

[lucas@skywalker perf]$ sudo ./perf stat -e branch-misses -a -- sleep 1

Performance counter stats for 'sleep 1':

1135044 branch-misses

1.001370775 seconds time elapsed

After (with task-clock):

[lucas@skywalker perf]$ sudo ./perf stat -e branch-misses -e task-clock -a -- sleep 1

Performance counter stats for 'sleep 1':

1070111 branch-misses # 0.534 M/sec
2002.730893 task-clock-msecs # 1.999 CPUs

1.001640292 seconds time elapsed

Signed-off-by: Lucas De Marchi <lucas.de.marchi@xxxxxxxxx>

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index c6df377..c70d720 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -357,7 +357,8 @@ static void abs_printout(int counter, double avg)
ratio = avg / total;

fprintf(stderr, " # %10.3f IPC ", ratio);
- } else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter)) {
+ } else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter) &&
+ runtime_branches_stats.n != 0) {
total = avg_stats(&runtime_branches_stats);

if (total)
@@ -365,7 +366,7 @@ static void abs_printout(int counter, double avg)

fprintf(stderr, " # %10.3f %% ", ratio);

- } else {
+ } else if (runtime_nsecs_stats.n != 0) {
total = avg_stats(&runtime_nsecs_stats);

if (total)

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