[PATCH 6/7] powerpc/mm: 64-bit: tlb handler micro-optimization

[Scott Wood]

On Thu, 19 May 2011 07:54:48 +1000
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> On Wed, 2011-05-18 at 16:51 -0500, Scott Wood wrote:
> > On Thu, 19 May 2011 07:37:47 +1000
> > Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:
> > 
> > > On Wed, 2011-05-18 at 16:05 -0500, Scott Wood wrote:
> > > > A little more speed up measured on e5500.
> > > > 
> > > > Setting of U0-3 is dropped as it is not used by Linux as far as I can
> > > > see.
> > > 
> > > Please keep them for now. If your core doesn't have them, make them an
> > > MMU feature.
> > 
> > We have them, it was just an attempt to clean out unused things to speed up
> > the miss handler.  I'll drop that part if you think we'll use it in the
> > future.
> 
> I never know for sure ... damn research people ... :-)
> 
> I'd rather keep them for now, does it make a significant difference ?

It was minor but measurable (wouldn't have been worthwhile except as part
of a series of small things that add up), but upon trying again I was able
to reorder slightly and fit it in without seeing an impact.

-Scott