HDF5 Based Parallel I/O Techniques for Multi-Zone Structured Grids CFD Applications

Computational fluid dynamics (CFD) is one of the most important high performance computing (HPC) areas. CFD applications commonly access large volumes of data. In case of large-scale CFD parallel computing, serial I/O performance does not match the computing performance, hence it becomes the performance bottleneck. Parallel I/O is an effective way to solve this problem. HDF5 (hierarchical data format v5) has provided excellent mechanisms to manage scientific data as well as effective ways to implement parallel I/O. High-order simulator for aerodynamics (HOSTA) is a multi-zone structured grids CFD application that can solve real world flow problems. This paper implements the parallel I/O method in HOSTA, based on the HDF5 file format and corresponding parallel I/O application programming interface. Detailed performance evaluation is performed with real CFD simulation cases on a HPC system equipped with 6 I/O service nodes. The results show that our method is both scalable and efficient. For a delta wing test case, parallel I/O achieves the performance speedup of 21.27 compared with the serial I/O. It achieves maximal I/O throughput of 5.81GBps and improves the application’s performance by over 10%, as compared with the original code. For a simple airfoil test case with larger grid size, our parallel I/O achieves maximal I/O throughput of 6.72GBps.