Multicore-aware parallel temporal blocking of stencil codes for shared and distributed memory

New algorithms and optimization techniques are needed to balance the accelerating trend towards bandwidth-starved multicore chips. It is well known that the performance of stencil codes can be improved by temporal blocking, lessening the pressure on the memory interface. We introduce a new pipelined approach that makes explicit use of shared caches in multicore environments and minimizes synchronization and boundary overhead. For clusters of shared-memory nodes we demonstrate how temporal blocking can be employed successfully in a hybrid shared/distributed-memory environment. 1 Temporal blocking of stencil codes 1.1 Baseline and test bed The Jacobi algorithm is a simple method for solving boundary value problems. It serves here as a prototype for more advanced stencil-based methods like the lattice-Boltzmann algorithm (LBM). In three dimensions, one stencil (cell) update is described by Bi, j,k