Hiding Global Communication Latency in the GMRES Algorithm on Massively Parallel Machines

Hiding Global Communication Latency in the GMRES Algorithm on Massively Parallel Machines

In the Generalized Minimal Residual Method (GMRES), the global all-to-all communication required in each iteration for orthogonalization and normalization of the Krylov base vectors is becoming a performance bottleneck on massively parallel machines. Long latencies, system noise and load imbalance cause these global reductions to become very costly global synchronizations. In this work, we prop...

Hiding Communication Latency in Data Parallel Applications

Interprocessor communication times can be a significant fraction of the overall execution time required for data parallel applications. Large communication to computation ratios of the tasks performed by these applications results in suboptimal performance when executed on data parallel architectures. We present an alternate architectural framework, referred to as concurrently communicating SIM...

Hiding global synchronization latency in the preconditioned Conjugate Gradient algorithm

Scalability of Krylov subspace methods suffers from costly global synchronization steps that arise in dot-products and norm calculations on parallel machines. In this work, a modified Conjugate Gradient (CG) method is presented that removes the costly global synchronization steps from the standard CG algorithm by only performing a single non-blocking reduction per iteration. This global communi...

Parallel Molecular Dynamics: Communication Requirements for Massively Parallel Machines

Molecular mechanics and dynamics are becoming widely used to perform simulations of molecular systems from large-scale computations of maten'als to the design and modeling of drug compounds. In this paper we address two major issues: a good decomposition method that can take advantage of fu iun massively parallel processing systems for modest-sized problems in ihe range of 50,000 a t o m and th...

Communication Latency Hiding