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- Choose PIO settings that are good enough to avoid having the model crash while reading input settings.
- Often the default settings will not work, especially on vary large or very small processor counts.
- Disable history output and restart files for all components, then use short (5-10 days) simulations to determine an optional processor layout.
- Without disabling IO, short simulations will be dominated by I/O costs and will give misleading performance numbers.
- Note that input and initialization times are not included in SYPD computations.
- For ATM, you can disable output by simply setting nhtfrq (described here) in user_nl_cam to something longer than the length of the model run.
- By default, MPAS always writes output during the first timestep. You can disable this by setting config_write_output_on_startup = .false. in user_nl_mpas-o:
- Without disabling IO, short simulations will be dominated by I/O costs and will give misleading performance numbers.
- Once you have a reasonable processor layout without I/O, use 1 month simulations to test PIO settings.
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