Re: [PATCH 0/5] sched/debug: decouple sched_stat tracepoints from CONFIG_SCHEDSTATS

From: Srikar Dronamraju
Date: Tue Jun 21 2016 - 04:34:38 EST


* Josh Poimboeuf <jpoimboe@xxxxxxxxxx> [2016-06-17 12:43:22]:

> NOTE: I didn't include any performance numbers because I wasn't able to
> get consistent results. I tried the following on a Xeon E5-2420 v2 CPU:
>
> $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do echo -n performance > $i; done
> $ echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo
> $ echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct
> $ echo 0 > /proc/sys/kernel/nmi_watchdog
> $ taskset 0x10 perf stat -n -r10 perf bench sched pipe -l 1000000
>
> I was going to post the numbers from that, both with and without
> SCHEDSTATS, but then when I tried to repeat the test on a different day,
> the results were surprisingly different, with different conclusions.
>
> So any advice on measuring scheduler performance would be appreciated...
>
> Josh Poimboeuf (5):
> sched/debug: rename and move enqueue_sleeper()
> sched/debug: schedstat macro cleanup
> sched/debug: 'schedstat_val()' -> 'schedstat_val_or_zero()'
> sched/debug: remove several CONFIG_SCHEDSTATS guards
> sched/debug: decouple 'sched_stat_*' tracepoints' from
> CONFIG_SCHEDSTATS
>

This patchset looks good to me.

Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

--
Thanks and Regards
Srikar Dronamraju