Messages in this thread | | | Date | Wed, 15 Jun 2005 01:19:11 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] Move some variables into the "most_readonly" section?? |
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On Tue, Jun 14, 2005 at 04:17:14PM -0700, Christoph Lameter wrote: > On Wed, 15 Jun 2005, Andi Kleen wrote: > > > > Hmm. No. The bigger cpu maps may benefit from cacheline alignment for > > > even for read access. > > > > Why? Can you please explain that. It doesn't make sense to me. > > Its more likely to get a big piece of the array in a single > cacheline if the array starts at the beginning of a cacheline. > > If these maps would start in the middle of a cacheline then additional > cacheline fetches may become necessary to scan an array etc.
But the CPUs do prefetching anyways for that. Do you have numbers that this is actually worth it?
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