[yocto] [feature request] avoid getting the server stuck because of high "-j" value

[Burton, Ross]

Alex's comment is right that the semantics of PARALLEL_MAKE are GNU Make
specific so you might find some recipes don't handle anything but there
being -j values.  You might have a little bit of fixing to do.

Ross

On 4 August 2017 at 13:00, Burton, Ross <ross.burton at intel.com> wrote:

> It's not just feasible but you can do it right now.
>
> PARALLEL_MAKE is the variable that sets how parallel the build should be.
> By default we pass -j<number of processors".
>
> Just set it to -l2.5 or whatever load average you want.
>
> Ross
>
> On 4 August 2017 at 11:58, Gianfranco Costamagna <
> costamagnagianfranco at yahoo.it> wrote:
>
>> Hello Yocto developers!
>>
>>
>>
>>
>> recently I found a really nice make feature, that tunes at runtime the
>> number of parallel
>>
>> execution jobs, according to the current system load [1].
>>
>>
>> I think such a feature would be really nice on server were multiple yocto
>> builds are run in parallel,
>>
>> and when people forgets to put the correct number of parallel build jobs.
>>
>>
>> E.g., a number around CPU+1 is nice, but sometimes CPU*2 gives better
>> results.
>>
>> Unfortunately if somebody else starts a build in parallel, that CPU*2
>> locks really hard the server, specially
>>
>> when building qt-based projects (e.g. qtbase, qtwebengine).
>>
>>
>> Tuning such value at runtime will probably end in faster compilation time
>> and lower swapping on remote
>>
>> servers.
>>
>> (I would think also to something that checks the amount of free RAM)
>>
>>
>>
>> is such a feature feasible?
>> should I open a bug for it?
>>
>>
>> [1] https://www.gnu.org/software/make/manual/html_node/Parallel.
>> html#Parallel
>>
>>
>> thanks,
>>
>>
>> Gianfranco
>> --
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>>
>
>
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