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chtMultiRegionFoam is slower in parallel than serial

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Old   September 11, 2023, 15:41
Default chtMultiRegionFoam is slower in parallel than serial
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Roberto
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Hi All,
I am trying to run a multi region case in parallel.
However, it runs slower in parallel than serial.
So, I went back to the tutorial case multiRegionHeater (within heatTransfer/chtMultiRegionFoam) and I ran it both in serial and parallel.
The parallel run is slower than the serial run.
I have also tried other tutorial cases with buoyantPimpleFoam and solidFoam and I was able to run them in parallel, and their performance is better than the serial run's.
Anyone any ideas?
How can I make chtMultiRegionFoam run faster in parallel.

Thanks,
Roberto

P.S. I am using OpenFoam-v2012.
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Old   September 11, 2023, 16:27
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Domenico Lahaye
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For small cases (small number of cells) communication (between processors) might (emphasis on might) dominate computations (on each processor).
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Old   September 12, 2023, 13:55
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Roberto
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Thanks dlahaye for your response.
You are right.
I have increased the number of volumes in the tutorial example, and now the parallel case runs faster than the serial.
Thanks for the help!
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