From a1f3d56761df31f0ffeb215b974e26d5613e92a4 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 13 May 2016 15:01:03 +0900 Subject: [PATCH] perf stat: Use cpu-clock event for cpu targets Currently 'perf stat' always counts task-clock event by default. But it's somewhat confusing for system-wide targets (especially with 'sleep N' as the 'sleep' task just sleeps and doesn't use cputime). Changing to cpu-clock event instead for that case makes more sense IMHO. Before: # perf stat -a sleep 0.1 Performance counter stats for 'system wide': 403.038603 task-clock (msec) # 4.001 CPUs utilized 150 context-switches # 0.372 K/sec 7 cpu-migrations # 0.017 K/sec 71 page-faults # 0.176 K/sec 23,705,169 cycles # 0.059 GHz 15,888,166 instructions # 0.67 insn per cycle 3,326,078 branches # 8.253 M/sec 87,643 branch-misses # 2.64% of all branches 0.100737009 seconds time elapsed # After: # perf stat -a sleep 0.1 Performance counter stats for 'system wide': 404.271182 cpu-clock (msec) # 4.000 CPUs utilized 143 context-switches # 0.354 K/sec 13 cpu-migrations # 0.032 K/sec 73 page-faults # 0.181 K/sec 22,119,220 cycles # 0.055 GHz 13,622,065 instructions # 0.62 insn per cycle 2,918,769 branches # 7.220 M/sec 85,033 branch-misses # 2.91% of all branches 0.101073089 seconds time elapsed # Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Andi Kleen Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1463119263-5569-3-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-stat.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 16a923c1633b..efdd23221c16 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -1905,6 +1905,9 @@ static int add_default_attributes(void) } if (!evsel_list->nr_entries) { + if (target__has_cpu(&target)) + default_attrs0[0].config = PERF_COUNT_SW_CPU_CLOCK; + if (perf_evlist__add_default_attrs(evsel_list, default_attrs0) < 0) return -1; if (pmu_have_event("cpu", "stalled-cycles-frontend")) { -- 2.20.1