Re: Q: PREFETCH_STRIDE/16

David S. Miller (davem@redhat.com)
Thu, 23 May 2002 09:21:55 -0700 (PDT)


From: David Mosberger <davidm@napali.hpl.hp.com>
Date: Thu, 23 May 2002 09:26:54 -0700

That code certainly wasn't optimized for ia64. Furthermore, I also do
not like the prefetch distance it's using. In fact, in my ia64-patch,
I use the following code instead:

prefetchw(pmd + j + PREFETCH_STRIDE/sizeof(*pmd));

This is more sensible (because it really does prefetch by the
PREFETCH_STRIDE distance) and it also happens to run (slightly) faster
on Itanium.

All of these particular prefetches are amusing, with or without your
fix, considering there are other more powerful ways to optimize this
stuff. :-)

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