What factors could cause the scalability issue on a 10-core CPU?

Posted by JackWM on Stack Overflow See other posts from Stack Overflow or by JackWM
Published on 2012-09-04T15:18:41Z Indexed on 2012/09/04 15:38 UTC
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cpu

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shared-memory

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multicore

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intel

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cpu-architecture

I am tuning the performance of parallel Java programs. And want to check the impacts from the Architecture. I'm look into the Intel 10-core CPU, Intel(R) Xeon(R) CPU E7-L8867. I found my program only scales up to 5 cores. What could be the causes? I'm considering the Architecture effects. e.g. memory contention? More specifically,

Are the 10 cores symmetric to each other?
How many memory controllers does it have?

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