Performance Modeling of a Geophysics Application to Accelerate the Tuning of Over-decomposition Parameters through Simulation

Autor: Keller Tesser, Rafael, Mello Schnorr, Lucas, Legrand, Arnaud, Heinrich, Christian, Dupros, Fabrice, Alexandre Navaux, Philippe Olivier
Přispěvatelé: Instituto de Informática da UFRGS (UFRGS), Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), Performance analysis and optimization of LARge Infrastructures and Systems (POLARIS ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'Informatique de Grenoble (LIG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Concurrency and Computation: Practice and Experience
Concurrency and Computation: Practice and Experience, Wiley, In press, pp.1-21. ⟨10.1002/cpe.5012⟩
Concurrency and Computation: Practice and Experience, inPress, pp.1-21. ⟨10.1002/cpe.5012⟩
ISSN: 1532-0626
1532-0634
DOI: 10.1002/cpe.5012⟩
Popis: International audience; Finite-difference methods are commonplace in High Performance Computing applications. Despite their apparent regularity, they often exhibit load imbalance that damages their efficiency. We characterize the spatial and temporal load imbalance of Ondes3D, a typical finite-differences application dedicated to earthquake mod-eling. Our analysis reveals imbalance originating from the structure of the input data, and from low-level CPU optimizations. Ondes3D was successfully ported to AMPI/CHARM++ using over-decomposition and MPI process migration techniques to dynamically rebalance the load. However, this approach requires careful selection of the over-decomposition level, the load balancing algorithm, and its activation frequency. These choices are usually tied to application structure and platform characteristics. In this article, we propose a workflow that leverages the capabilities of SimGrid to conduct such study at low experimental cost. We rely on a combination of emulation, simulation, and application modeling that requires minimal code modification and manages to capture both spatial and temporal load imbalance to faithfully predict the performance of dynamic load balancing. We evaluate the quality of our simulation by comparing simulation results with the outcome of real executions and demonstrate how this approach can be used to quickly find the optimal load balancing configuration for a given application/hardware configuration.
Databáze: OpenAIRE
Externí odkaz: