Performance measurement of magnetohydrodynamic code for space plasma on typical scalar-type supercomputer systems with a large number of cores

The computational performance of magnetohydrodynamic (MHD) code is evaluated on two typical scalar-type supercomputer systems. We have carried out performance tuning of a three-dimensional MHD code for space plasma simulations on the HA8000 (with 8192 cores) and SR16000/L2 (with 1344 cores) supercomputer systems. For parallelization of the MHD code, we use four different methods, that is, regular one-dimensional, two-dimensional and three-dimensional domain decomposition methods and a cache-hit type of three-dimensional domain decomposition method. We found that the regular three-dimensional decomposition of the MHD model is suitable for the HA8000 system, and the cache-hit type of three-dimensional decomposition is suitable for SR16000/L2 systems. As a result of these runs, we achieved a performance efficiency of almost 15% on the HA8000 and 20% on the SR16000/L2 for MHD code.