Optimizing Irregular Adaptive Applications on Multi-threaded Processors: The Case of Medium-Grain Parallel Delaunay Mesh Generation

The Importance of parallel mesh generation and emerging growth of SMT architectures raise an important question of adapting parallel mesh generation software to the SMT architecture. In this work we focus on Parallel Constrained Delaunay Mesh Generation. We explore medium grain parallelism at the sub-domain level. This parallel approach targets commercially available SMT processors. Our goal is to improve the performance of the existing, MPI-based, parallel mesh generation software (PCDT) by exploiting multi-threading inside a single SMT chip. This report presents a parallel mesh generation software based on medium grain parallelism, which we developed on top of the existing PCDT program. By extending PCDT instead of creating completely new software, we reduced the development complexity. We achieved 100% code reuse. Experimental evaluation shows that using different contexts of an SMT processor can improve the performance of a parallel mesh generation software. However, the medium grain approach suffers from significant synchronization overhead caused by different threads working on the same sub-domain. There are 2 general contributions of this work. First, we extended the coarse-grain parallel mesh generation software (PCDT), combining the coarse-grain approach with a medium-grain approach. The second contribution is that we significantly improved the performance of the PCDT software using the optimizations developed for the MPCDT code and the SMT architecture. These changes made PCDT faster than Triangle, the best publicly available 2D Delaunay mesh generation software, when executed on a single physical SMT processor.