[U-Boot] [PATCH] Reduce build times

[Matthias Weißer]

Am 02.11.2011 07:54, schrieb Wolfgang Denk:
> U-Boot Makefiles contain a number of tests for compiler features etc.
> which so far are executed again and again.  On some architectures
> (especially ARM) this results in a large number of calls to gcc.
>
> This patch makes sure to run such tests only once, thus largely
> reducing the number of "execve" system calls.
>
> Example: number of "execve" system calls for building the "P2020DS"
> (Power Architecture) and "qong" (ARM) boards, measured as:
> 	->  strace -f -e trace=execve -o /tmp/foo ./MAKEALL<board>
> 	->  grep execve /tmp/foo | wc -l
>
> 	Before: After:	Reduction:
> ==================================
> P2020DS 20555	15205	-26%
> qong	31692	14490	-54%
>
> As a result, built times are significantly reduced, typically by
> 30...50%.
>
> Signed-off-by: Wolfgang Denk<wd at denx.de>
> Cc: Andy Fleming<afleming at gmail.com>
> Cc: Kumar Gala<galak at kernel.crashing.org>
> Cc: Albert Aribaud<albert.aribaud at free.fr>
> cc: Graeme Russ<graeme.russ at gmail.com>
> cc: Mike Frysinger<vapier at gentoo.org>
> ---

Nice. Some additional numbers:

zmx25: make
-----------
real    1m47.546s 0m57.213s -53%
user    1m39.698s 0m54.831s
sys     0m24.798s 0m9.509s


zmx25: make -j2
---------------
real    0m56.791s 0m32.187s -57%
user    1m38.478s 0m55.571s
sys     0m24.522s 0m9.513s

Tested-by: Matthias Weisser <weisserm at arcor.de>

Matthias