关键词: CALMET, 多核处理器, OpenMP, 并行化

Abstract: Now, processor is transforming from single core to multi-core because of technical limitation of processor manufacture process. Multi-core processor is the current standard configuration and mainstream for personal computer (PC) in recent years. Majority of meteorological programs are still serial, so it wastes CPU resources. As two major parallel environments, i.e. MPI and OpenMP, each has its own advantages. MPI and OpenMP are designed for distributed memory computers and shared memory computers, respectively. To a program, large changes are required by using MPI, while small changes by using OpenMP. Therefore, OpenMP is more suitable for multi-core processor’s parallel computing. The method of parallelization by using OpenMP is introduced for CALMET as an example. It shows that a significant speedup can be gained by adding simply a few lines of directive codes into CALMET source codes. Parallelization method includes four main steps, i.e. analyzing performance of the serial program to find the most time-consuming part which should be parallelized; parallelizing loops using OpenMP parallel-do directive, then modifying the intermediate variables and making it private to single thread; compiling and running parallel program, and comparing the performance of parallel and serial program; verifying parallel and serial outputs to make sure they are the same.