Messages in this thread Patch in this message | | | From | Ramkumar Ramachandra <> | Subject | [PATCH 2/2] perf tool: don't print bogus data on -e cycles | Date | Mon, 30 Sep 2013 16:43:05 +0530 |
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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 <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ramkumar Ramachandra <artagnon@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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