Re: [XenPPC] copy_page speedup using dcbz on target

[Hollis Blanchard <hollisb@xxxxxxxxxx>]

On Fri, 2006-12-15 at 16:40 -0500, poff wrote:
> > So do you have a patch for copy_page()?
> 
> In Xen for PPC, the only copy_page() is in arch/powerpc/mm.c:
> 
> extern void copy_page(void *dp, void *sp)
> {
>     if (on_systemsim()) {
>         systemsim_memcpy(dp, sp, PAGE_SIZE);
>     } else {
>         memcpy(dp, sp, PAGE_SIZE);
>     }
> }

Correct.

> 1) Also copy_page is not referenced in current Xen sources?

In that case, why are you playing with it?

> 2) dcbz depends on cacheability and cache alignment.
>    Should a newname be given to this version of copy_page()?

"page" indicates cacheline-aligned.

Who calls copy_page() with non-cacheable memory?

> 3) Useful when PPC must do page copies in place of 'page flipping'.

So you're saying we should worry about it later?

-- 
Hollis Blanchard
IBM Linux Technology Center


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