Re: [RFC PATCH 1/1] local.conf.sample: update suggestions for BB_NUMBER_THREADS and PARALLEL_MAKE

[Darren Hart <dvhart@linux.intel.com>]

On 06/17/2011 08:16 PM, Joshua Lock wrote:
> It's been suggested that BB_NUMBER_THREADS should be 2 * the number of cores
> and PARALLEL_MAKE should be equal to the number of cores available on the
> build machine.
> 
> Update local.conf.sample to suggest this.
> 
> Signed-off-by: Joshua Lock <josh@linux.intel.com>
> ---
>  meta-yocto/conf/local.conf.sample |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/meta-yocto/conf/local.conf.sample b/meta-yocto/conf/local.conf.sample
> index ea32b81..43d06e6 100644
> --- a/meta-yocto/conf/local.conf.sample
> +++ b/meta-yocto/conf/local.conf.sample
> @@ -9,7 +9,9 @@ CONF_VERSION = "1"
>  #SSTATE_DIR ?= "${TOPDIR}/sstate-cache"
>  
>  # Uncomment and set to allow bitbake to execute multiple tasks at once.
> -# For a quadcore, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would
> +# Recommended values are twice the number of processor cores for
> +# BB_NUMBER_THREADS and the number of processor cores for PARALLEL_MAKE
> +# For a quadcore, BB_NUMBER_THREADS = "8", PARALLEL_MAKE = "-j 4" would

Hrm, where is this coming from? In my experience it works better the
other way around. We probably also need to be explicit about cores
versus threads.


>  # be appropriate.
>  # BB_NUMBER_THREADS = "4"
>  # Also, make can be passed flags so it run parallel threads e.g.:

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel