[Buildroot] [Question] Including only needed makefiles?
Yann E. MORIN
yann.morin.1998 at free.fr
Wed Feb 17 09:59:23 UTC 2016
Yamada-san, Thomas, All,
On 2016-02-17 09:11 +0100, Thomas Petazzoni spake thusly:
> On Wed, 17 Feb 2016 13:00:26 +0900, Masahiro Yamada wrote:
> > I am not an active developer of Buildroot.
> > Apology if I am asking a silly question.
> Your question is not silly at all!
Indeed. No question is stupid. You're welcome to ask.
[--SNIP--]
> > [2]
> > If we achieve the perfect dependency in Kconfig,
> > perhaps can we include makefiles that are really
> > enabled by Kconfig? For example, like this?
> >
> > pkg-$(BR2_PACKAGE_BUSYBOX) += busybox
> > pkg-$(BR2_PACKAGE_LAME) += lame
> > pkg-$(BR2_PACKAGE_GZIP) += gzip
> > ...
> >
> > include $(addprefix packages, $(addsuffix Makefike, $(pkg-y)))
>
> I propose such a change two years ago, see my RFC patch series at:
>
> http://lists.busybox.net/pipermail/buildroot/2014-March/092548.html
>
> The main complexity is that while target packages all have a Config.in
> options, it is not the case for host packages. And therefore, changing
> to a per package makefile inclusion requires adding lots and lots of
> Config.in options for host packages.
>
> Another issue (explained in the cover letter) was that we could no
> longer use sub-directories in packages, such as
> package/qt5/qt5base/qt5base.mk.
Well, except with Yamada's proposal (or something similar), we could
explicitly manage the sub-directories, like so:
pkg-$(BR2_PACKAGE_FOO) += foo
pkg-$(BR2_PACKAGE_BAR) += sub-dir/bar
-include $(addprefix packages/,$(foreach p,$(pkg),$(p)/$(notdir $(p)).mk))
Of course, that means explicitly listing all packages, instead of the
current glob-include. But sinc ewe're already explicitly source-ing
Config.in files, this would make it symetric for the .mk files as well.
> If you look at the feedback of the patch series, it was generally quite
> positive, but this needs more work, and is only saving a few seconds of
> make parsing, which are not such a big deal. So the effort is fairly
> big for limited savings.
Indeed, I don't believe the few startup seconds are that problematic.
Yes, they are annoying.
It takes roughly 3s on my machine (dual core-i5 with SSD), but I can see
that it could take quite a bit more on leww powerful machines,
especially those with rotating rust...
> I would personally rank implementing top-level parallel build at a much
> higher priority level than this micro-optimization.
Agreed.
Regards,
Yann E. MORIN.
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