perf stat: Fix -nan% output in perf stat noise printouts
Before:
0 CPU-migrations # 0.000 M/sec ( +- -nan% )
After:
0 CPU-migrations # 0.000 M/sec ( +- 0.00% )
Also factor out the noise printing function.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/n/tip-z89h2v1bk1mikcbsf7e6v34q@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 924d18c..845ded8 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -382,6 +382,16 @@
return WEXITSTATUS(status);
}
+static void print_noise_pct(double total, double avg)
+{
+ double pct = 0.0;
+
+ if (avg)
+ pct = 100.0*total/avg;
+
+ fprintf(stderr, " ( +-%6.2f%% )", pct);
+}
+
static void print_noise(struct perf_evsel *evsel, double avg)
{
struct perf_stat *ps;
@@ -390,8 +400,7 @@
return;
ps = evsel->priv;
- fprintf(stderr, " ( +- %7.3f%% )",
- 100 * stddev_stats(&ps->res_stats[0]) / avg);
+ print_noise_pct(stddev_stats(&ps->res_stats[0]), avg);
}
static void nsec_printout(int cpu, struct perf_evsel *evsel, double avg)
@@ -635,9 +644,8 @@
fprintf(stderr, " %18.9f seconds time elapsed",
avg_stats(&walltime_nsecs_stats)/1e9);
if (run_count > 1) {
- fprintf(stderr, " ( +-%5.2f%% )",
- 100*stddev_stats(&walltime_nsecs_stats) /
- avg_stats(&walltime_nsecs_stats));
+ print_noise_pct(stddev_stats(&walltime_nsecs_stats),
+ avg_stats(&walltime_nsecs_stats));
}
fprintf(stderr, "\n\n");
}