* [PATCH] local.conf.sample: Suggest parallelism of twice the number of cores.
@ 2013-01-09 18:14 Robert P. J. Day
2013-01-09 18:31 ` Saul Wold
0 siblings, 1 reply; 3+ messages in thread
From: Robert P. J. Day @ 2013-01-09 18:14 UTC (permalink / raw)
To: OE Core mailing list
To be consistent with the Yocto Quick Start Guide, recommend that
parallelism represent twice the number of cores on a multi-core
machine.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
---
diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample
index 859eb93..46187ce 100644
--- a/meta/conf/local.conf.sample
+++ b/meta/conf/local.conf.sample
@@ -24,9 +24,9 @@
#
#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".
#
# Machine Selection
#
--
========================================================================
Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
========================================================================
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] local.conf.sample: Suggest parallelism of twice the number of cores.
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
0 siblings, 1 reply; 3+ messages in thread
From: Saul Wold @ 2013-01-09 18:31 UTC (permalink / raw)
To: Robert P. J. Day; +Cc: OE Core mailing list
On 01/09/2013 10:14 AM, Robert P. J. Day wrote:
>
> To be consistent with the Yocto Quick Start Guide, recommend that
> parallelism represent twice the number of cores on a multi-core
> machine.
>
> Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
>
> ---
>
> diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample
> index 859eb93..46187ce 100644
> --- a/meta/conf/local.conf.sample
> +++ b/meta/conf/local.conf.sample
> @@ -24,9 +24,9 @@
> #
> #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).
Sau!
> #
> # Machine Selection
> #
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] local.conf.sample: Suggest parallelism of twice the number of cores.
2013-01-09 18:31 ` Saul Wold
@ 2013-01-09 18:43 ` Enrico Scholz
0 siblings, 0 replies; 3+ messages in thread
From: Enrico Scholz @ 2013-01-09 18:43 UTC (permalink / raw)
To: openembedded-core; +Cc: Saul Wold
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
^ permalink raw reply [flat|nested] 3+ messages in thread
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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
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