[U-Boot] [PATCH] Reduce build times

[Tom Rini]

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>
>> 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