Messages in this thread | | | Date | Fri, 05 Aug 2011 13:13:37 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [x86] Fix prefetch instruction |
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On 08/05/2011 09:18 AM, Christoph Lameter wrote: > The prefetchnta instruction used for prefetching on x86 is a special instruction > used for streaming that is usually used to avoid polluting the l2 and l3 caches. > The cacheline will be evicted rapidly. > > What we need is a prefetch that puts the cacheline in all levels of the cache hierachy instead. > Change the instruction to do that. > > Acked-by: Andi Kleen <ak@linux.intel.com> > Signed-off-by: Christoph Lameter <cl@linux.com> >
Have you done any performance analysis on this versus the null case? I know there are some workloads where it helps, but if it hurts as many as it helps...
-hpa
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