[bitbake-devel] [PATCH] bitbake-user-manual-execution.xml: Update parallelization note.

[Richard Purdie]

On Wed, 2014-06-18 at 11:22 -0400, Robert P. J. Day wrote:
> Update the note to explain that current versions of BitBake
> automatically calculate the proper values for BB_NUMBER_THREADS

The current version of bitbake doesn't though.

There is an *OE* helper function which the default local.conf files use.

Cheers,

Richard

>  and
> PARALLEL_MAKE so you no longer need to set those values manually.
> 
> Signed-off-by: Robert P. J. Day <rpjday at crashcourse.ca>
> 
> ---
> 
> diff --git a/doc/bitbake-user-manual/bitbake-user-manual-execution.xml b/doc/bitbake-user-manual/bitbake-user-manual-execution.xml
> index 8514f23..6d49fb6 100644
> --- a/doc/bitbake-user-manual/bitbake-user-manual-execution.xml
> +++ b/doc/bitbake-user-manual/bitbake-user-manual-execution.xml
> @@ -29,11 +29,23 @@
>      </para>
> 
>      <note>
> -        Prior to executing BitBake, you should take advantage of parallel
> -        thread execution by setting the
> -        <link linkend='var-BB_NUMBER_THREADS'><filename>BB_NUMBER_THREADS</filename></link>
> -        variable in your <filename>local.conf</filename>
> -        configuration file.
> +        In order to take advantage of parallel thread execution on your build
> +        host, earlier versions of BitBake recommended setting the following
> +        variables in your project's <filename>local.conf</filename> file,
> +        based on your host's number of CPUs or multithreading
> +        capability:
> +        <literallayout class='monospaced'>
> +     BB_NUMBER_THREADS ?= ...
> +     PARALLEL_MAKE ?= ...
> +        </literallayout>
> +        The current version of BitBake now handles this automatically by
> +        assigning default values to those variables as follows:
> +        <literallayout class='monospaced'>
> +     BB_NUMBER_THREADS ?= "${@oe.utils.cpu_count()}"
> +     PARALLEL_MAKE ?= "-j ${@oe.utils.cpu_count()}"
> +        </literallayout>
> +        so you no longer need to worry about this, unless you specifically
> +        want to override this for some reason.
>      </note>
> 
>      <section id='parsing-the-base-configuration-metadata'>
> 
> -- 
> 
> ========================================================================
> Robert P. J. Day                                 Ottawa, Ontario, CANADA
>                         http://crashcourse.ca
> 
> Twitter:                                       http://twitter.com/rpjday
> LinkedIn:                               http://ca.linkedin.com/in/rpjday
> ========================================================================