Big difference between Elapsed Time and CPU Time

Asked May 08 '14 at 05:07

Active May 08 '14 at 05:35

Viewed 980 times

VTune hotspots analysis reports my program's execution time (elapsed time) was 60 seconds out of which only 10 seconds are reported as "CPU Time". I'm trying to where the remaining 50 seconds was spent. Using Windows Process Monitor's File System Activity, I see my program spent 5 seconds doing disk I/O. This still leaves 45 seconds unaccounted for.

There are two threads in my program, according to VTune, one of those thread consumed 99% of the CPU Time. I don't see how these two threads given their execution profiles could explain the lost time.

Any thoughts?

edited May 08 '14 at 05:35

asked May 08 '14 at 05:07

DigitalEye

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Could be waiting for resources/being blocked/sleeping I would guess. – Allan S. Hansen May 08 '14 at 05:42
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Sometimes the elapsed time adds the time of the threads, thus your program ran for 30 sec, waited 5 sec. It still leaves 15 sec but might be worth considering. – usr1234567 May 08 '14 at 05:44
It might be in scheduler queue waiting for its turn to get cpu time. – Nachiket Kate May 08 '14 at 12:14

Big difference between Elapsed Time and CPU Time

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