[bitbake-devel] Should multiconfig save build time?

[chris.laplante at agilent.com]

> We have need to generate 6 slighly different images, with different dedicated applications and use cases, but they're all destined for
> the same hardware.
> We have multiconfig set to build these 6 variants.  Clearly, they'll all share a majority of underlying packages.
> While the bitbake initialization takes a long time (with multiconfig), we were under the impression that it could save time during the
> actual build process because it could have the potential to reuse packages already built from mc A for mc B if the inputs to the recipes
> are unchanged (if same xxx_FEATURES, same arch, etc.).
> 
> This was a guess on our part since we initially didn't assign different tmp directories for each conf.  So, the <WORKDIR> didn't change
> between mc builds.  That actually was causing some issues until we realized that separate tmp dirs was recommended for them.
> Since they all now have separate tmp dirs, they clearly are not going to share work dirs, so, now we're questioning our original
> assumption about any build-time speed benefit.

Have you considered whether you actually need multiconfig in this case? If the arch and distro features don't change, you should just be able to have multiple image recipes.

Chris