When only the cycles event is requested:
$ perf stat -e cycles dd if=/dev/zero of=/dev/null count=1000000
1000000+0 records in
1000000+0 records out
512000000 bytes (512 MB) copied, 0.26123 s, 2.0 GB/s
Performance counter stats for 'dd if=/dev/zero of=/dev/null count=1000000':
911,626,453 cycles # 0.000 GHz
0.262113350 seconds time elapsed
The 0.000 GHz comment in the output is totally bogus and misleading. It
happens because update_shadow_stats() doesn't touch runtime_nsecs_stats;
it is only written when a requested counter matches a SW_TASK_CLOCK. In
our case, since we have only requested HW_CPU_CYCLES,
runtime_nsecs_stats is unavailable. So, omit printing the comment
altogether.
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net>
Signed-off-by: Ramkumar Ramachandra <artag...@gmail.com>
---
tools/perf/builtin-stat.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index f686d5f..cc167ae 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -918,11 +918,10 @@ static void abs_printout(int cpu, int nr, struct
perf_evsel *evsel, double avg)
print_stalled_cycles_backend(cpu, evsel, avg);
} else if (perf_evsel__match(evsel, HARDWARE, HW_CPU_CYCLES)) {
total = avg_stats(&runtime_nsecs_stats[cpu]);
-
- if (total)
- ratio = 1.0 * avg / total;
-
- fprintf(output, " # %8.3f GHz ", ratio);
+ if (total) {
+ ratio = avg / total;
+ fprintf(output, " # %8.3f GHz ",
ratio);
+ }
} else if (runtime_nsecs_stats[cpu].n != 0) {
char unit = 'M';
--
1.8.4.477.g5d89aa9
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