[U-Boot] [PATCH] Reduce build times

[Premi, Sanjeev]

> -----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

Compiled u-boot works fine on the board as well.

Tested-by: Sanjeev Premi <premi at ti.com> 

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