[Buildroot] [RFC v3 00/30] Add per-package staging feature

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Fabio Porcedda,

On Tue,  3 Mar 2015 10:17:05 +0100, Fabio Porcedda wrote:

> this patch set aims to improve build reproducibility by using a
> per-package staging directory.
> Also this feature aims to enable as default the top-level parallel make.

Interesting! I must say I'm a bit worried about the implications of
having to pass custom -I and -L flags all the time: we did arrange the
compiler do not require those (by configuration for the internal
toolchain case, and using the wrapper for the external toolchain case).

Could you give some hints about the performance impact of those copies
of the staging directory? Does it continue to make the top-level
parallel build thing useful?

I.e can you compare in terms of build time the following cases:

 * Normal non-top-level parallel build.
 * A top-level parallel build without this PPS feature
 * A top-level parallel build with this PPS feature

Preferably something with a fairly deep dependency tree, i.e lots of
small packages that depend on each other. A X.org stack + gtk2 would be
a good example.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com