Re: [patch v4 0/18] sched: simplified fork, release load avg andpower awareness scheduling

From: Borislav Petkov
Date: Mon Jan 28 2013 - 06:26:23 EST


On Mon, Jan 28, 2013 at 11:44:44AM +0100, Mike Galbraith wrote:
> On Mon, 2013-01-28 at 10:55 +0100, Borislav Petkov wrote:
> > On Mon, Jan 28, 2013 at 06:17:46AM +0100, Mike Galbraith wrote:
> > > Zzzt. Wish I could turn turbo thingy off.
> >
> > Try setting /sys/devices/system/cpu/cpufreq/boost to 0.
>
> How convenient (test) works too.
>
> So much for turbo boost theory. Nothing changed until I turned load
> balancing off at NODE. High end went to hell (gee), but low end...
>
> Benchmark Version Machine Run Date
> AIM Multiuser Benchmark - Suite VII "1.1" performance-no-node-load_balance Jan 28 11:20:12 2013
>
> Tasks Jobs/Min JTI Real CPU Jobs/sec/task
> 1 436.3 100 13.9 3.9 7.2714
> 5 2637.1 99 11.5 7.3 8.7903
> 10 5415.5 99 11.2 11.3 9.0259
> 20 10603.7 99 11.4 24.8 8.8364
> 40 20066.2 99 12.1 40.5 8.3609
> 80 35079.6 99 13.8 75.5 7.3082
> 160 55884.7 98 17.3 145.6 5.8213
> 320 79345.3 98 24.4 287.4 4.1326

If you're talking about those results from earlier:

Benchmark Version Machine Run Date
AIM Multiuser Benchmark - Suite VII "1.1" performance Jan 28 08:09:20 2013

Tasks Jobs/Min JTI Real CPU Jobs/sec/task
1 438.8 100 13.8 3.8 7.3135
5 2634.8 99 11.5 7.2 8.7826
10 5396.3 99 11.2 11.4 8.9938
20 10725.7 99 11.3 24.0 8.9381
40 20183.2 99 12.0 38.5 8.4097
80 35620.9 99 13.6 71.4 7.4210
160 57203.5 98 16.9 137.8 5.9587
320 81995.8 98 23.7 271.3 4.2706

then the above no_node-load_balance thing suffers a small-ish dip at 320
tasks, yeah.

And AFAICR, the effect of disabling boosting will be visible in the
small count tasks cases anyway because if you saturate the cores with
tasks, the boosting algorithms tend to get the box out of boosting for
the simple reason that the power/perf headroom simply disappears due to
the SOC being busy.

> 640 100294.8 98 38.7 570.9 2.6118
> 1280 115998.2 97 66.9 1132.8 1.5104
> 2560 125820.0 97 123.3 2256.6 0.8191

I dunno about those. maybe this is expected with so many tasks or do we
want to optimize that case further?

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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