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Subject[tip:perf/core] perf stat: Do not print ratio when task-clock event is not counted
Commit-ID:  7255fe2a42c612f2b8fe4c347f0a5f0c97d85a46
Gitweb: http://git.kernel.org/tip/7255fe2a42c612f2b8fe4c347f0a5f0c97d85a46
Author: Lucas De Marchi <lucas.de.marchi@gmail.com>
AuthorDate: Sun, 15 Nov 2009 12:05:08 -0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 15 Nov 2009 15:25:50 +0100

perf stat: 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@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091115140507.GB21561@skywalker.lan>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
tools/perf/builtin-stat.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
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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