* Neil Horman <nhor...@tuxdriver.com> wrote: > Looking at the specific cpu counters we get this: > > Base: > Total time: 0.179 [sec] > > Performance counter stats for 'perf bench sched messaging -- bash -c echo 1 > > /sys/module/csum_test/parameters/test_fire' (20 runs): > > 1571.304618 task-clock # 5.213 CPUs utilized > ( +- 0.45% ) > 14,423 context-switches # 0.009 M/sec > ( +- 4.28% ) > 2,710 cpu-migrations # 0.002 M/sec > ( +- 2.83% )
Hm, for these second round of measurements were you using 'perf stat -a -C ...'? The most accurate method of measurement for such single-threaded workloads is something like: taskset 0x1 perf stat -a -C 1 --repeat 20 ... this will bind your workload to CPU#0, and will do PMU measurements only there - without mixing in other CPUs or workloads. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/