Performance analysis and optimization on a parallel atmospheric general circulation model code

✍ Scribed by Lou, John Z.; Farrara, John D.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 163 KB
• Volume: 10
• Category: Article
• ISSN: 1040-3108
• DOI: 10.1002/(sici)1096-9128(199806)10:7<549::aid-cpe365>3.0.co;2-w

✦ Synopsis

An analysis is presented of the primary factors influencing the performance of a parallel implementation of the UCLA atmospheric general circulation model (AGCM) on distributedmemory, massively parallel computer systems. Several modifications to the original parallel AGCM code aimed at improving its numerical efficiency, load-balance and single-node code performance are discussed. The impact of these optimization strategies on the performance on two of the state-of-the-art parallel computers, the Intel Paragon and Cray T3D, is presented and analyzed. It is found that implementation of a load-balanced FFT algorithm results in a reduction in overall execution time of approximately 45% compared to the original convolutionbased algorithm. Preliminary results of the application of a load-balancing scheme for the physics part of the AGCM code suggest that additional reductions in execution time of 10-15% can be achieved. Finally, several strategies for improving the single-node performance of the code are presented, and the results obtained thus far suggest that reductions in execution time in the range of 35-45% are possible.