[Buildroot] [PATCH 7/8] package/autotools: add --{enable, disable}-{shared, static} automatically
Thomas Petazzoni
thomas.petazzoni at free-electrons.com
Tue Jun 14 06:54:30 UTC 2011
Hello,
Le Mon, 13 Jun 2011 23:39:41 +0200,
Peter Korsgaard <jacmet at uclibc.org> a écrit :
> Thomas> It's true that I haven't checked the impact on the build
> Thomas> time. Does it really build libraries twice ? Isn't only the
> Thomas> link stage performed twice ?
>
> Yes, in general it needs to build each source file twice because of
> the different compiler flags (E.G. -fPIC).
Ah, okay. True that I didn't check this closely.
> Which I first built normally (a) and then with make
> SHARED_STATIC_LIBS_OPTS='--disable-static --enable-shared' (b). The
> machine was busy doing other stuff, so you cannot completely trust the
> build time numbers, but here they are anyway:
>
> (a):
> real 27m14.481s
> user 45m4.601s
> sys 12m11.738s
>
> (b):
> real 28m56.879s
> user 44m16.506s
> sys 10m56.337s
>
> So no significant difference - B is even slightly slower here. Most of
> the time is spent building the toolchain.
Ok, interesting. Did you actually check that in the two different
builds, one was actually building the library object files twice ?
> A naturally leads to a bit bigger staging though:
>
> du -hs {a,b}/staging/
> 28M a/staging/
> 26M b/staging/
>
> But it (naturally) doesn't affect the image size:
> du -hs {a,b}/images
> 5.0M a/images
> 5.0M b/images
>
> So I think we should just leave it as it is for now.
Ok. Thanks a lot for doing this testing!
Thomas
--
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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