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From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: buildroot@busybox.net
Subject: [Buildroot] [PATCH 1/2] pkg-autotools: use --disable-dependency-tracking
Date: Fri, 29 Aug 2014 09:21:50 +0200	[thread overview]
Message-ID: <20140829092150.04986069@free-electrons.com> (raw)
In-Reply-To: <87tx4vrcg8.fsf@dell.be.48ers.dk>

Dear Peter Korsgaard,

On Fri, 29 Aug 2014 09:18:15 +0200, Peter Korsgaard wrote:
> >>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@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
rivi?res", which could roughly be translated as "the small streams make
the big rivers". Everything counts :-)

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

  reply	other threads:[~2014-08-29  7:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-28 21:03 [Buildroot] [PATCH 1/2] pkg-autotools: use --disable-dependency-tracking Thomas Petazzoni
2014-08-28 21:03 ` [Buildroot] [PATCH 2/2] packages: no longer pass --disable-dependency-tracking in individual packages Thomas Petazzoni
2014-08-29  7:18 ` [Buildroot] [PATCH 1/2] pkg-autotools: use --disable-dependency-tracking Peter Korsgaard
2014-08-29  7:21   ` Thomas Petazzoni [this message]
2014-08-29  7:58     ` Peter Korsgaard

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