Re: [PATCH 2/2] runqueue: Introduce load balanced task spawning

[Martin Jansa <martin.jansa@gmail.com>]

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On Mon, Aug 13, 2018 at 11:20:50PM +0200, Alexander Kanavin wrote:
> 2018-08-13 23:04 GMT+02:00 Andreas Müller <schnitzeltony@gmail.com>:
> > To get most out of build host, bitbake now detects if the CPU workload is low.
> > If so, additional tasks are spawned. Maximum 'dynamic' tasks are set by
> > BB_NUMBER_THREADS_LOW_CPU.
> 
> So the best improvement is going from 114.5 minutes to 113.5 minutes?
> I don't think it's worth the trouble. Maybe it's time to invest in 16
> (or even 32!) core amd threadripper? :)

IMHO the best improvement was for 3 BB_NUMBER_THREADS and possibly even
bigger improvement for 2 BB_NUMBER_THREADS.


>  2                 | 156m48.741s
> ------------------------------------
>  3                 | 126m27.426s
> ------------------------------------

...

> With the patch applied and BB_NUMBER_THREADS_LOW_CPU = "20" (as
> written in docs
> for max thread count)
> 
>  BB_NUMBER_THREADS | Build time [s]
> ------------------------------------
>  3                 | 114m48.105s

I'm running with 2 BB_NUMBER_THREADS on similar HW (8core Bulldozer
FX(tm)-8120, 32GB ram), because it leaves the desktop usable for other
stuff while some build is running on background.

With 4 BB_NUMBER_THREADS, big build and a bit of bad luck I was getting
4 do_compile tasks like qtbase, chromium, firefox and gimp at the same
time which either makes me drink too much coffee or even invites uncle
OOMK.

I quite like the idea behind BB_NUMBER_THREADS_LOW_CPU.

-- 
Martin 'JaMa' Jansa     jabber: Martin.Jansa@gmail.com

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