Abstract: The Saint-Venant equations can be used to describe the confluence process of unsteady flows in open channels. In large-scale hydrological simulation software, solving the numerical solution of the equations is the biggest bottleneck restricting the running time of the program. This paper analyzes the structure of the serial solving program and the hotspots of calculation, and explores the parallelism of the single-step simulation loop calculation section and instruction arrangement in the calculation- intensive program. A master-slave asynchronous parallel scheme is designed for the heterogeneous many-core architecture of the Sunway-TaihuLight supercomputer. The solver is ported, paralleled and accelerated based on MPI and athread libraries. SIMD technology is used to vectorize the slave-core’s calculation section, and double buffering strategies are used to optimize the communication process. The tests show that the performance of hot functions can be increased by more than 3 times on average compared with the computation before optimization. Within a million-unit scale, the speedup of parallel programs using many-core optimization can maintain growing linearly, which shows strong scalability in Sunway’s multi-nodes.

Key words: parallel computing, heterogeneous many-core processor, Saint-Venant equation, numerical simulation ,