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Serial Job Jumping from Core to Core

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Old   August 25, 2008, 11:15
Default Serial Job Jumping from Core to Core
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Hello, I'm running in Linux on an AMD Quad Core with a serial fluent case. My problem is that I cannot seem to set the core affinity and thus, the process is jumping from core to core all the time. This probably isn't that big of a deal but I would imagine it must be slowing the computations down some. I tried (set-affinity "0 1") hoping it would set the affinity for process 0 to core 1 but that doesn't seem to change anything. Anyone know the trick to doing this?
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Old   August 25, 2008, 11:21
Default Re: Serial Job Jumping from Core to Core
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You can do it with taskset, however, me experience on a dual-core AMD processor was that it actually slowed it down a little. Having said that, I haven't tried it with the quad core yet, and I would expect different behaviour between AMD and Intel systems, and also between single and dual socket.

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Old   August 25, 2008, 14:21
Default Re: Serial Job Jumping from Core to Core
Renato Pacheco
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it is normal to jump from core to core, since the processor knows by itself which is better to run the process. when I run it parallel, I can see that if the process is not using the full capacity, then it keeps on changing like what is happening to you.

it would be better if you run parallel on your quad core processor.
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