[Cbe-oss-dev] [RFC 3/3] powerpc: copy_4K_page tweaked for Cell
Mark Nelson
markn at au1.ibm.com
Fri Jun 20 12:25:02 EST 2008
On Fri, 20 Jun 2008 07:28:50 am Arnd Bergmann wrote:
> On Thursday 19 June 2008, Mark Nelson wrote:
> > .align 7
> > _GLOBAL(copy_4K_page)
> > dcbt 0,r4 /* Prefetch ONE SRC cacheline */
> >
> > addi r6,r3,-8 /* prepare for stdu */
> > addi r4,r4,-8 /* prepare for ldu */
> >
> > li r10,32 /* copy 32 cache lines for a 4K page */
> > li r12,128+8 /* prefetch distance*/
>
> Since you have a loop here anyway instead of the fully unrolled
> code, why not provide a copy_64K_page function as well, jumping in
> here?
That is a good idea. What effect will that have on how the code
patching will work?
>
> The inline 64k copy_page function otherwise just adds code size,
> as well as being a tiny bit slower. It may even be good to
> have an out-of-line copy_64K_page for the regular code, just
> calling copy_4K_page repeatedly.
Doing that sounds like it'll make the code patching easier.
Thanks!
Mark
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