cputime & clock time

Aymenad · March 14, 2024, 09:47

Hello,

I am interested in conducting a scalability study on OpenFOAM. I have added tags to calculate the execution time of each task.

I would like to understand the difference between cputime and clock time? And which one is more suitable for scalability studies?

Thank you.

Severus · March 19, 2024, 10:19

Hello,
The CPU time is basically the ExecutionTime that you see in your log file/terminal when your solver is running and is the time taken by the processor. Going by the documentation of OpenFOAM, the ExecutionTime is the elapsedCPUTime from the start.

clockTime is the real time. The clockTime will also depend on the other processes/software that are running in your PC.

I would use the CPU time for scalability study.

Thanks

March 14, 2024, 09:47	cputime & clock time	#1
Aymenad New Member Aymen Join Date: May 2023 Posts: 1 Rep Power: 0	Hello, I am interested in conducting a scalability study on OpenFOAM. I have added tags to calculate the execution time of each task. I would like to understand the difference between cputime and clock time? And which one is more suitable for scalability studies? Thank you.

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March 19, 2024, 10:19		#2
Severus Member Shravan Join Date: Mar 2017 Posts: 60 Rep Power: 9	Hello, The CPU time is basically the ExecutionTime that you see in your log file/terminal when your solver is running and is the time taken by the processor. Going by the documentation of OpenFOAM, the ExecutionTime is the elapsedCPUTime from the start. clockTime is the real time. The clockTime will also depend on the other processes/software that are running in your PC. I would use the CPU time for scalability study. Thanks