[bitbake-devel] Should multiconfig save build time?

[Alan Kozlay]

All,

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.

So, is mc expected to be any faster than, say, 6 separate invocations of
non-mc bitbake whilst switching out the local.conf between them?

Thanks,
-Alan

-- 
Alan Kozlay
VES Solutions, LLC
Alan Kozlay <alan.kozlay at ves.solutions>
DESK 443-595-7734
CELL 443-752-0323
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