Why CPU time is longer than Elasped time?

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12-03-2009

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Why CPU time is longer than Elasped time?

I thought a program's elapsed time, some program language call it real time, should be the time of a program from start to finish. And it should be equal or longer than CPU time. This is true for the most of the cases. However, I do see some of my programs CPU time is longer than Elapsed time.
This is from Syncsort run log (ran on solaries):

Elapsed time: 0:09:27.35 CPU time: 0:17:13.85

I saw the same happened on one of my SAS programs (also ran on solaries).

Can anyone explain to me why? Is elapsed time really reflacts program time from start to end? If yes, how can a program still consumes CPU after it completed?

visio2000

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12-03-2009

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A guess: maybe it was multi-threaded and grabbed 2 cpu's.

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