FAMOUS, faster: using parallel computing techniques to accelerate the FAMOUS/HadCM3 climate model with a focus on the ratiative transfer algorithm

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  2. Dr Hiro Yamazaki
Author(s)Hanappe P, Beurive A, Laguzet F, Steels L, Bellouin N, Boucher O, Yamazaki YH, Aina T, Allen M
Publication type Article
JournalGeoscientific Model Development Discussions
ISSN (print)1991-9611
ISSN (electronic)1991-962X
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We have optimised the atmospheric radiation algorithm of the FAMOUS climate model on several hardware platforms. The optimisation involved translating the Fortran code to C and restructuring the algorithm around the computation of a single air column. A task queue and a thread pool are used to distribute the computation to several pro- cessors. Finally, four air columns are packed together in a single data structure and computed simultaneously using Single Instruction Multiple Data operations. The modified algorithm runs more than 50 times faster on the CELL’s Synergistic Pro- cessing Elements than on its main PowerPC processing element. On Intel-compatible processors, the new radiation code runs 4 times faster and on graphics processors, using OpenCL, more than 2.5 times faster, as compared to the original code. Because the radiation code takes more than 60 % of the total CPU time, FAMOUS executes more than twice as fast. Our version of the algorithm returns bit-wise identical results, which demonstrates the robustness of our approach.
PublisherCopernicus GmbH
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