Dynamic Adaptively Refined Mesh Simulations on 1M+ Cores
Authors: Brian T. N. Gunney (Lawrence Livermore National Laboratory)
Abstract: Patch-based structured adaptive mesh refinement (SAMR) is widely used for high-resolution simulations. Combined with modern supercomputers, it can provide simulations of unprecedented size and resolution, but managing dynamic SAMR meshes at large scales is challenging. Distributed mesh management is a scalable approach, but early distributed algorithms still had trouble scaling past O(100K) MPI tasks. This poster presents two critical regridding algorithms, integrated into that approach to ensure efficiency of the whole. The clustering algorithm is an extension of the tile-clustering approach, making it more flexible and efficient in both clustering and parallelism. The partitioner is a new algorithm designed to mitigate the network congestion experienced by its predecessor. We evaluated performance using weak- and strong-scaling benchmarks designed to be difficult for dynamic adaptivity. Results show good scaling on up to 1.5M cores and 2M MPI tasks. Detailed timing diagnostics suggest scaling would continue well past that.
Two-page extended abstract: pdf