Flexible and efficient parallel I/O for large-scale multi-component simulations

In this paper, we discuss our experience of providing high performance parallel I/O for a large-scale, on-going, multi-disciplinary simulation project for solid propellant rockets. We describe the performance and data management issues observed in this project and present our solutions, including (1) support for relatively fine-grained distribution of irregular datasets in parallel I/O, (2) a flexible data management facility for inter-module communication, and (3) two schemes to overlap computation with I/O. Performance results obtained from both development and production platforms show that our I/O optimizations can dramatically reduce the simulation's visible I/O cost, as well as the number of disk files, and significantly improve the overall performance. Meanwhile, our data management facility helps to provide simulation developers with simple user interfaces for parallel I/O.