linux-kernel - Re: [PATCH 0/5] sched/debug: decouple sched_stat tracepoints from CONFIG

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Date:	Tue, 21 Jun 2016 13:57:14 +0530
From:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:	Josh Poimboeuf <jpoimboe@...hat.com>
Cc:	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org,
	Mel Gorman <mgorman@...hsingularity.net>,
	Matt Fleming <matt@...eblueprint.co.uk>
Subject: Re: [PATCH 0/5] sched/debug: decouple sched_stat tracepoints from
 CONFIG_SCHEDSTATS

* Josh Poimboeuf <jpoimboe@...hat.com> [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@...ux.vnet.ibm.com>

-- 
Thanks and Regards
Srikar Dronamraju