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- Get working PIO settings, so that the model will not crash while reading input settings. Often the default settings will not work, especialy on vary large or very small processor counts.
- Disable history output and restart files for all components. Then you can use short (5-10 days) simulations to determine an optional processor layout. Otherwise, short simulations will be dominated by I/O costs and will give misleading performance numbers. Input and initialization times are not included in SYPD computations. (Note that disabling history write during the first timestep of MPAS-O is not simple, as I understand it, and this needs to be taken into acount when evaluating model performance. Doug Jacobsen (Unlicensed) should verify this, and perhaps expand on the topic. I do not know if the same issue arises with the other MPAS components.)
- Once you have a reasonable processor layout without I/O, use 1 month simulations to test PIO settings.
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