Optimization for Hybrid MPI-OpenMP Programs on a Cluster of SMP PCs

This paper applies a Hybrid MPI-OpenMP program-ming model with a thread-to-thread communication method on a cluster of Dual Intel Xeon Processor SMPs connected by a Gigabit Ethernet network. The experiments include the well-known HPL and CG benchmarks. We also describe optimization tech-niques to get a high cache hit ratio with the given architecture. As a result, the hybrid model shows performance prominence over the pure MPI model with about 27 % for CG and 12 % for HPL. Besides, with a relatively small programming effort, we have succeeded in reducing the cache miss ratio and thus significantly risen up performance for the CG bench-mark as much as 4.5 times in some cases.