Re: Linux: more cores = less concurrency.

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On 2011-04-11 22:39, James Cloos wrote:
"GA" == Glyn Astill<glynastill@xxxxxxxxxxx>  writes:
GA>  I was hoping someone had seen this sort of behaviour before,
GA>  and could offer some sort of explanation or advice.

Jesper's reply is probably most on point as to the reason.

I know that recent Opterons use some of their cache to better manage
cache-coherency.  I presum recent Xeons do so, too, but perhaps yours
are not recent enough for that?

Better cache-coherence also benefits, but it does nothing to
the fact that remote DRAM fetches is way more expensive
than local ones. (Hard numbers to get excact nowadays).

--
Jesper

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