Why is a single thread spread across CPU's?

Posted by Marcus Lindblom on Super User See other posts from Super User or by Marcus Lindblom
Published on 2009-08-20T07:04:10Z Indexed on 2011/06/25 16:24 UTC
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Windows

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Performance

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cpu

I'm just curious why the scheduler constantly moves an app between CPUs, rather than keeping it on one. It looks a bit silly to have 4 cores at 25% rather than one at 100%.

Does it has to do with heat, or is it more efficient somehow? Do other OS's do it differently?

Insights or links to in-depth stuff would be nice. (Couldn't find much myself.)

Update:

By "spread out" I don't mean that it executes on several cpu's at once, but is being moved from one to the other several times per second, making the effect that it looks spread out.

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