Re: [PATCH RFC] [x86] Optimize copy-page by reducing impact from HW prefetch

From: Andi Kleen
Date: Wed Jun 22 2011 - 22:29:18 EST

On Thu, Jun 23, 2011 at 09:01:19AM +0800, Ma, Ling wrote:
> Yes, I also have tested 64bit atom, it got 11.6% improvement.

That's a nice improvement, however I should add that in my experience
copy_page micro benchmark improvements do not necessarily translate to
real world improvements. Most simple micro benchmark do not simulate
the typical page fault access pattern very well.

> Because older CPU almost all use prefetch-next-line mechanism, the patch should be useful to them.

Old in this case is P4 and ancient early stepping K8 only.

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