Transactional Memory for Algebraic Multigrid Smoothers

This paper extends our early investigations in which we compared transactional memory to traditional OpenMP synchronization mechanisms [7, 8]. We study similar issues for algebraic multigrid (AMG) smoothers in hypre [16], a mature and widely used production-quality linear solver library. We compare the transactional version of the Gauss-Seidel AMG smoother to an omp critical version and the default hybrid Gauss-Seidel smoother, as well as the \(l_1\) variations of both Gauss-Seidel and Jacobi smoothers. Importantly, we present results for real-life 2-D and 3-D problems discretized by the finite element method that demonstrate the TM option can outperform the existing methods, often by orders of magnitude, in terms of the recently introduced performance measure of run time per quality.