At 01:59 -0500 12/7/11, Stan Hoeppner wrote:

On 7/12/2011 1:12 AM, Rainer Frey wrote:

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On 11.07.2011, at 17:03, Stan Hoeppner wrote:

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The R410 is a two socket Xeon box with max 2 x 6 core CPUs. The 24 CPUs you see is the result of HyperThreading being enabled. I'd disable HT if I were you, or those boxen mine.

Why?

It's a troubleshooting step. HT can cause weird problems with some systems/kernels. It can also decrease performance with some workloads. As with anything, if it doesn't provide benefit, turn if off to reduce complexity and potential problems.

Or, another way, HT only helps when having twice as many (apparent) processors running at half the (effective) speed is good for your specific workload. Just because it's a band-waggon it doesn't mean you have to jump onto it.

David

-- David Ledger - Freelance Unix Sysadmin in the UK. HP-UX specialist of hpUG technical user group (www.hpug.org.uk) david.ledger@ivdcs.co.uk www.ivdcs.co.uk