[PATCH] powerpc: Align hot loops of memset() and backwards_memcpy()

[Nicholas Piggin]

On Sun, 25 Sep 2016 21:36:59 +1000
Anton Blanchard <anton at samba.org> wrote:

> Hi Nick,
> 
> > Hmm. If we execute this loop once, we'll only fetch additional nops.
> > Twice, and we make up for them by not fetching unused instructions.
> > More than twice and we may start winning.
> > 
> > For large sizes it probably helps, but I'd like to see what sizes
> > memset sees.  
> 
> I noticed this in an nginx web serving test. There are some 1 and 2
> iteration calls, but quite a few larger ones - get_empty_filp() goes for
> 4 iterations and sk_prot_alloc() for 26 iterations.

Hi Anton,

I didn't have anything against the patch as such, I just wondered if
it's likely to be an overall win.

Thanks,
Nick