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CCSM/CAM3 Successfully ported to Sun F6800

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CCSM/CAM3 Successfully ported to Sun F6800

At Purdue, we have successfully ported CCSM3 to run on up to 24 cpus of our Sun F6800s. The work is more fully described on our CCSM wiki at . Visit the "Recent Changes" section to see our description of porting to the Sun and also the POWER3 IBM cluster at Purdue. The porting was performed by Hangsang Bae of Purdue's ITaP and took something less than a week. Performance on the Sun's is proving to be suboptimal, but more tuning may improve the situation.

-Matthew Huber


Sometimes getting CCSM "load balancing" correct is problematic. This is the process of assigning a "correct" number of processors to each CCSM component. I have been working on a "Load Balancing HowTo" which I hope to be able to post after the holidays. Email me if you need a couple pointers to get started.

George R Carr Jr


Here is a brief description of porting process.

Building CCSM on Sun machines is basically setting up appropriate compiler flags that enable correct compilation of CCSM. For example, accepting extended source lines, promoting single precision to douple precision, and adding module search paths. It was also necessary to make some site-specific changes - long path name space for POP (80-->128), and short variable name length (<20) in csh because of SunOS's implementation of csh. More details are available at

To run CCSM jobs on Sun F6800, we need to invoke mprun commands that enable MPMD type execution for CCSM. Here is an example:
'mprun: -np 1 cpl: -np 4 cam: -np 2 csim: -np 4 pop: -np 1 clm'
Necessary changes were made to run.$mach file to generate this command.

Load balancing problem has not been investigated much on our platform because of limited access to the resources.

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