Tuning Spectral Element Preconditioners for Parallel Scalability on GPUs

Malachi Phillips; Stefan Kerkemeier; Paul Fischer

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arXiv · 2110.07663

Tuning Spectral Element Preconditioners for Parallel Scalability on GPUs

Malachi Phillips·Stefan Kerkemeier·Paul Fischer

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Abstract

The Poisson pressure solve resulting from the spectral element discretization of the incompressible Navier-Stokes equation requires fast, robust, and scalable preconditioning. In the current work, a parallel scaling study of Chebyshev-accelerated Schwarz and Jacobi preconditioning schemes is presented, with special focus on GPU architectures, such as OLCF's Summit. Convergence properties of the Chebyshev-accelerated schemes are compared with alternative methods, such as low-order preconditioners combined with algebraic multigrid. Performance and scalability results are presented for a variety of preconditioner and solver settings. The authors demonstrate that Chebyshev-accelerated-Schwarz methods provide a robust and effective smoothing strategy when using $p$-multigrid as a preconditioner in a Krylov-subspace projector. The variety of cases to be addressed, on a wide range of processor counts, suggests that performance can be enhanced by automated run-time selection of the preconditioner and associated parameters.

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Malachi Phillips, Stefan Kerkemeier, Paul Fischer. 2021-10-14. Tuning Spectral Element Preconditioners for Parallel Scalability on GPUs. https://arxiv.org/abs/2110.07663

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