Complex-Geometry 3D Computational Fluid Dynamics with Automatic Load Balancing
József Bakosi, Mátyás Constans, Zoltán Cs. Horváth, Ákos Kovács, László Környei, Marc R.J. Charest, Aditya K. Pandare, Paula Rutherford, Jacob I. Waltz · Fluids · 2023
We present an open-source code, Xyst, intended for the simulation of complex-geometry 3D compressible flows. The software implementation facilitates the effective use of the largest distributed-memory machines, combining data-, and task-parallelism on top of the Charm++ runtime system. Charm++’s execution model is asynchronous by default, allowing arbitrary overlap of computation and communication. Built-in automatic load balancing enables redistribution of arbitrarily heterogeneous computational load based on real-time CPU load measurement at negligible cost. The runtime system also features automatic checkpointing, fault tolerance, resilience against hardware failure, and supports power- and energy-aware computation. We verify and validate the numerical method and demonstrate the benefits of automatic load balancing for irregular workloads.