[MITgcm-support] MPI scaling of coupled aim-ocn runs

[Andrew Keats]

Hello everybody,

I have just begun setting up a coupled run based on the code in the  
verification/cpl_aim+ocn directory.  By editing SIZE.h's I have set  
up runs with different combinations of processes (1 ocn / 1 atm ; 2  
ocn / 1 atm ; 1 ocn / 2 atm ; 2 ocn / 2 atm ; 1 ocn / 3 atm) and the  
fastest run seems to be the one with 1 ocn / 2 atm.

We are eventually hoping to use this code to do multiple thousand- 
year runs for the last glaciation (at some point will attempt  
coupling with Tarasov's glacial system model).  Does anyone know what  
the best configuration of processes/threads is for running the  
coupled model?  I haven't tried multithreading yet, only MPI.  Also,  
is there a way to tell how well synchronized the atmosphere and ocean  
processes are?  Does it happen that one ends up waiting for the other  
if the ratio of the time steps is off?

Many thanks,

Andrew



--
Andrew Keats
NSERC Postdoctoral Fellow
Department of Physics and Physical Oceanography
Memorial University of Newfoundland