Javelin: A Scalable Implementation for Sparse Incomplete LU Factorization
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In this work, we present a new scalable incomplete LU factorization framework called Javelin to be used as a preconditioner for solving sparse linear systems with iterative methods. Javelin allows for improved parallel factorization on shared-memory many-core systems by packaging the coefficient matrix into a format that allows for high performance sparse matrix-vector multiplication and sparse triangular solves with minimal overheads. The framework achieves these goals by using a collection of traditional permutations, point-to-point thread synchronizations, tasking, and segmented prefix scans in a conventional compressed sparse row format. Moreover, this framework stresses the importance of co-designing dependent tasks, such as sparse factorization and triangular solves, on highly-threaded architectures. Using these changes, traditional fill-in and drop tolerance methods can be used, while still being able to have observed speedups of up to 42x on 68 Intel Knights Landing cores and 12x on 14 Intel Haswell cores.
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