[PATCH 9/9] powerpc: optimise csum_partial() call when len is constant

[Scott Wood]

On Tue, 2015-09-22 at 16:34 +0200, Christophe Leroy wrote:
> csum_partial is often called for small fixed length packets
> for which it is suboptimal to use the generic csum_partial()
> function.
> 
> For instance, in my configuration, I got:
> * One place calling it with constant len 4
> * Seven places calling it with constant len 8
> * Three places calling it with constant len 14
> * One place calling it with constant len 20
> * One place calling it with constant len 24
> * One place calling it with constant len 32
> 
> This patch renames csum_partial() to __csum_partial() and
> implements csum_partial() as a wrapper inline function which
> * uses csum_add() for small 16bits multiple constant length
> * uses ip_fast_csum() for other 32bits multiple constant
> * uses __csum_partial() in all other cases
> 
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
> ---
>  arch/powerpc/include/asm/checksum.h | 80 ++++++++++++++++++++++++++--------
> ---
>  arch/powerpc/lib/checksum_32.S      |  4 +-
>  arch/powerpc/lib/checksum_64.S      |  4 +-
>  arch/powerpc/lib/ppc_ksyms.c        |  2 +-
>  4 files changed, 62 insertions(+), 28 deletions(-)

Benchmarks?

-Scott