[Buildroot] [PATCH 1/2] pkg-autotools: use --disable-dependency-tracking

Thomas Petazzoni thomas.petazzoni at free-electrons.com
Fri Aug 29 07:21:50 UTC 2014

Dear Peter Korsgaard,

On Fri, 29 Aug 2014 09:18:15 +0200, Peter Korsgaard wrote:
> >>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni at free-electrons.com> writes:
>  > By default, automake does "dependency tracking", which allows the
>  > generated Makefile to contain the necessary dependencies to
>  > automatically rebuild the appropriate C files when included header
>  > files are changed. This dependency tracking is nice when doing active
>  > development on the package, but not really useful when doing a
>  > one-time build of the package. According to automake's
>  > documentation[1], disabling the dependency tracking provides a small
>  > speed-up.
>  > In some very unscientific measurements (i.e repeated only once), we
>  > have noticed a ~3.6% reduction of the total build time of a Buildroot
>  > toolchain after applying this patch.
>  > [1] http://www.gnu.org/software/automake/manual/html_node/Dependency-Tracking.html
> 3% isn't much, but OK - Committed both to next, thanks.

Well, I was indeed a bit disappointed by the small difference. But I
believe it anyway makes more sense than having a few random packages
pass --disable-dependency-tracking.

Also, as we say in French, "les petits ruisseaux font les grandes
rivières", which could roughly be translated as "the small streams make
the big rivers". Everything counts :-)

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering

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