Scheduling and memory optimizations for sparse direct solver on multi-core/multi-gpu duster systems

Xavier Lacoste 1, 2
Abstract : The ongoing hardware evolution exhibits an escalation in the number, as well as in the heterogeneity, of computing resources. The pressure to maintain reasonable levels of performance and portability forces application developers to leave the traditional programming paradigms and explore alternative solutions. PaStiX is a parallel sparse direct solver, based on a dynamic scheduler for modern hierarchical manycore architectures. In this thesis, we study the benefits and the limits of replacing the highly specialized internal scheduler of the PaStiX solver by two generic runtime systems: PaRSEC and StarPU. Thus, we have to describe the factorization algorithm as a tasks graph that we provide to the runtime system. Then it can decide how to process and optimize the graph traversal in order to maximize the algorithm efficiency for thetargeted hardware platform. A comparative study of the performance of the PaStiX solver on top of its original internal scheduler, PaRSEC, and StarPU frameworks is performed. The analysis highlights that these generic task-based runtimes achieve comparable results to the application-optimized embedded scheduler on homogeneous platforms. Furthermore, they are able to significantly speed up the solver on heterogeneous environments by taking advantage of the accelerators while hiding the complexity of their efficient manipulation from the programmer. In this thesis, we also study the possibilities to build a distributed sparse linear solver on top of task-based runtime systems to target heterogeneous clusters. To permit an efficient and easy usage of these developments in parallel simulations, we also present an optimized distributed interfaceaiming at hiding the complexity of the construction of a distributed matrix to the user.
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Contributor : Abes Star <>
Submitted on : Friday, October 30, 2015 - 11:12:07 AM
Last modification on : Wednesday, April 4, 2018 - 1:24:20 AM
Long-term archiving on : Friday, April 28, 2017 - 8:05:12 AM


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  • HAL Id : tel-01222565, version 1


Xavier Lacoste. Scheduling and memory optimizations for sparse direct solver on multi-core/multi-gpu duster systems. Distributed, Parallel, and Cluster Computing [cs.DC]. Université de Bordeaux, 2015. English. ⟨NNT : 2015BORD0016⟩. ⟨tel-01222565⟩



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