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From: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
To: openembedded-core@lists.openembedded.org
Cc: Saul Wold <sgw-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Subject: Re: [PATCH] local.conf.sample: Suggest parallelism of twice the number of cores.
Date: Wed, 09 Jan 2013 19:43:32 +0100	[thread overview]
Message-ID: <ly38ya8aej.fsf@ensc-virt.intern.sigma-chemnitz.de> (raw)
In-Reply-To: <50EDB793.7080202@linux.intel.com> (Saul Wold's message of "Wed,  09 Jan 2013 10:31:47 -0800")

Saul Wold <sgw-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> writes:

>>   #PARALLEL_MAKE = "-j 4"
>>   #
>> -# For a quad-core machine, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would
>> -# be appropriate for example.
>> -
>> +# If you have a multi-core machine, you would normally set both of these variables
>> +# to twice the number of cores.  So for a quad-core machine, it would be appropriate
>> +# to set BB_NUMBER_THREADS = "8" and PARALLEL_MAKE = "-j 8".
>
> I think adding a note to ensure that hyperthreading is enabled would
> be appropriate, then number of threads = number of hyperthreaded cores
> (4 vs 8).

what about a general

| BB_NUMBER_THREADS ??= "${@os.sysconf(os.sysconf_names['SC_NPROCESSORS_ONLN'])}"

in bitbake.conf?  Or the sqrt() of it in in both PARALLEL_MAKE and
BB_NUMBER_THREADS...


Enrico



      reply	other threads:[~2013-01-09 18:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-09 18:14 [PATCH] local.conf.sample: Suggest parallelism of twice the number of cores Robert P. J. Day
2013-01-09 18:31 ` Saul Wold
2013-01-09 18:43   ` Enrico Scholz [this message]

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