[yocto] why do numerous .bb files set "PARALLEL_MAKE"?

[Joshua Lock]

On 04/11/11 08:57, Robert P. J. Day wrote:
> 
>   stumbled over this so i did a more thorough search:
> 
> $ grep -w PARALLEL_MAKE $(find . -name *.bb)
> ./meta/recipes-qt/qt-apps/qmmp_0.5.1.bb:PARALLEL_MAKE = ""
> ./meta/recipes-core/eggdbus/eggdbus_0.6.bb:PARALLEL_MAKE = ""
> ./meta/recipes-core/gettext/gettext_0.16.1.bb:PARALLEL_MAKE = ""
> ./meta/recipes-core/gettext/gettext_0.18.1.1.bb:#PARALLEL_MAKE = ""
> ./meta/recipes-bsp/pciutils/pciutils_3.1.7.bb:PARALLEL_MAKE = ""
> ./meta/recipes-extended/sat-solver/sat-solver_git.bb:PARALLEL_MAKE=""
> ./meta/recipes-extended/bash/bash_3.2.48.bb:PARALLEL_MAKE = ""
> ./meta/recipes-extended/tcp-wrappers/tcp-wrappers_7.6.bb:PARALLEL_MAKE = ""
> ./meta/recipes-extended/groff/groff_1.20.1.bb:PARALLEL_MAKE = ""
> ... more snipped ...
> 
>   why are individual recipes setting PARALLEL_MAKE to the empty
> string?  it's a *build* option, why would it have any relevance to
> individual .bb files?

Because that individual BB file has problems being run with parallel
make (make -j).

> 
>   conversely, i don't see a single .bb file that sets
> BB_NUMBER_THREADS.  the above just looks ... odd.

That's the amount of threads BitBake creates, tasks it will run in parallel.

Cheers,
Joshua
-- 
Joshua Lock
        Yocto Project "Johannes factotum"
        Intel Open Source Technology Centre