Tese de

Aluno: Arthur Francisco Lorenzon
Orientador: Prof. Dr. Antonio Carlos Schneider Beck Filho

Título: Aurora: Seamless Optimization of OpenMP Applications
Linha de Pesquisa: Sistemas Embarcados

Data: 30/05/2018
Horário: 09h
Local: Prédio 43412 – Sala 215 (sala de videoconferência), Instituto de Informática

Banca Examinadora:
– Prof. Dr. Antônio Tadeu Azevedo Gomes (LNCC)
– Prof. Dr. Luigi Carro (UFRGS)
– Prof. Dr. Laércio Lima Pilla (UFSC – por videoconferência)

Presidente da Banca: Prof. Dr. Antonio Carlos Schneider Beck Filho

Abstract: Efficiently exploiting thread-level parallelism has been challenging for software developers. As many parallel applications do not scale with the number of cores, blindly increasing the number of threads may not produce the best results in performance or energy. However, the task of rightly choosing the ideal amount of threads is not straight-forward: many variables are involved (e.g. off-chip bus saturation and overhead of data-synchronization), which will change according to different aspects of the system at hand (e.g., input set, micro-architecture) and even during execution. To address this complex scenario, this thesis presents Aurora. It is capable of automatically finding, at run-time and with minimum overhead, the optimal number of threads for each parallel region of the application and readapt in cases the behavior of a region changes during execution. Aurora works with OpenMP and is completely transparent to both designer and end-user: given an OpenMP application binary, Aurora optimizes it without any code transformation or recompilation. By executing fifteen well-known benchmarks on four multi-core processors, Aurora improves the trade-off between performance and energy by up to: 98% over the standard OpenMP execution; 86% over the built-in feature of OpenMP that dynamically adjusts the number of threads; and 91% over a feedback-driven threading emulation.

Keywords: Parallel computing, energy and performance optimization, software tuning, OpenMP.