• Wolfgang Denk's avatar
    Reduce build times · cca4e4ae
    Wolfgang Denk authored
    
    
    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: default avatarWolfgang Denk <wd@denx.de>
    Cc: Andy Fleming <afleming@gmail.com>
    Cc: Kumar Gala <galak@kernel.crashing.org>
    Cc: Albert Aribaud <albert.aribaud@free.fr>
    cc: Graeme Russ <graeme.russ@gmail.com>
    cc: Mike Frysinger <vapier@gentoo.org>
    Tested-by: default avatarGraeme Russ <graeme.russ@gmail.com>
    Tested-by: default avatarMatthias Weisser <weisserm@arcor.de>
    Tested-by: default avatarSanjeev Premi <premi@ti.com>
    Tested-by: default avatarSimon Glass <sjg@chromium.org>
    Tested-by: default avatarMacpaul Lin <macpaul@gmail.com>
    Acked-by: default avatarMike Frysinger <vapier@gentoo.org>
    cca4e4ae