SilentLain's Blog

Angstrom distribution uses bitbake to build the entire distribution. There are 2 parameters for speeding up bitbake:

PARALLEL_MAKE: this is passed to make so setting it to “-j X” is handy (where value of X depends on number of CPU cores)

BB_NUMBER_THREADS: amount of bitBake threads used to run tasks such as do_fetch, do_configure, do_compile etc. Do not set too big value or machine will melt and you will loose control over it ;)

The 2 parameters can be found in /setup-scripts/conf/local.conf, the default setting for beagleboard is “–j2” for PARALLEL_MAKE and “2” for BB_NUMBER_THREADS.

References:
http://marcin.juszkiewicz.com.pl/2008/04/07/speeding-up-bitbake-builds/
http://sinofinnovation.wordpress.com/2012/03/03/parallel-bitbake-compilation/