[U-Boot] [PATCH] Reduce build times

[Simon Glass]

On Wed, Nov 2, 2011 at 8:37 AM, Tom Rini <tom.rini at gmail.com> wrote:
> On Wed, Nov 2, 2011 at 7:49 AM, Premi, Sanjeev <premi at ti.com> wrote:
>>> -----Original Message-----
>>> From: u-boot-bounces at lists.denx.de
>>> [mailto:u-boot-bounces at lists.denx.de] On Behalf Of Wolfgang Denk
>>> Sent: Wednesday, November 02, 2011 12:24 PM
>>> To: u-boot at lists.denx.de
>>> Cc: Graeme Russ; Kumar Gala; Albert Aribaud; Andy Fleming
>>> Subject: [U-Boot] [PATCH] Reduce build times
>>>
>>> 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>

Tested-by: Simon Glass <sjg at chromium.org>

>>> 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>
>>> ---
>>
>> Results for OMAP3EVM.
>> (Tried 5 times just to be sure as I see >50% reduction.)
>>
>>        Before  After
>>        ------  ------
>> real    109.03  49.78
>> user     71.43  29.06
>> sys      26.83   7.66
>
> Over here omap3_evm wall-clock time on make -j12 goes from 27sec to 10sec.
>
> --
> Tom
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For Tegra2 Seaboard (armv7) and -j15 or so: before and after times:

full build (clobber, config) 17.177s -> 7.060s
incremental build 7.432s -> 2.267s

Thank you!

Regards,
Simon