[bitbake-devel] [PATCH 2/2] runqueue: Introduce load balanced task spawning

[Andre McCurdy]

On Mon, Aug 13, 2018 at 2:30 PM, Andreas Müller <schnitzeltony at gmail.com> wrote:
> On Mon, Aug 13, 2018 at 11:20 PM, Alexander Kanavin
> <alex.kanavin at gmail.com> wrote:
>> 2018-08-13 23:04 GMT+02:00 Andreas Müller <schnitzeltony at 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? :)
>>
> Indeed - but I have to wait till next holiday to assemble such kind of machine.
>
> I still can't believe the results are that disappointing...

I wonder if you've experimented with the opposite approach, ie
spawning fewer tasks when CPU load is very high? If a single
do_compile task can fully load all CPUs, not running other tasks in
parallel with it (especially another do_compile) might give some
benefit?

Dynamically boosting and dynamically lowering BB_NUMBER_THREADS based
on overall CPU load both seem like logical things to do.