On Mon, Oct 28, 2013 at 05:24:38PM +0100, Ingo Molnar wrote: > > * 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 I wasn't, but I will... Neil
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