Domain-Specific Acceleration and Auto-Parallelization of Legacy Scientific Code in FORTRAN 77 using Source-to-Source Compilation

Massively parallel accelerators such as GPGPUs, manycores and FPGAs represent a powerful and affordable tool for scientists who look to speed up simulations of complex systems. However, porting code to such devices requires a detailed understanding of heterogeneous programming tools and effective strategies for parallelization. In this paper we present a source to source compilation approach with whole-program analysis to automatically transform single-threaded FORTRAN 77 legacy code into OpenCL-accelerated programs with parallelized kernels. The main contributions of our work are: (1) whole-source refactoring to allow any subroutine in the code to be offloaded to an accelerator. (2) Minimization of the data transfer between the host and the accelerator by eliminating redundant transfers. (3) Pragmatic auto-parallelization of the code to be offloaded to the accelerator by identification of parallelizable maps and reductions. We have validated the code transformation performance of the compiler on the NIST FORTRAN 78 test suite and several real-world codes: the Large Eddy Simulator for Urban Flows, a high-resolution turbulent flow model; the shallow water component of the ocean model Gmodel; the Linear Baroclinic Model, an atmospheric climate model and Flexpart-WRF, a particle dispersion simulator. The automatic parallelization component has been tested on as 2-D Shallow Water model (2DSW) and on the Large Eddy Simulator for Urban Flows (UFLES) and produces a complete OpenCL-enabled code base. The fully OpenCL-accelerated versions of the 2DSW and the UFLES are resp. 9x and 20x faster on GPU than the original code on CPU, in both cases this is the same performance as manually ported code.Comment: 12 pages, 5 figures, submitted to "Computers and Fluids" as full paper from ParCFD conference entr

Refactorización en código Fortran heredado

Este artículo exhibe los obstáculos hallados por los programadores en las tareas de mantenimiento de software heredado escrito en Fortran. Por un lado se se~nalan las dificultades que se presentan en los procesos de comprensión, adaptación y mejora de este tipo de software. Por otro lado se encuadra una solución a este problema proponiendo la refactorización como técnica para ser aplicada en dichos procesos, intentando además, desmitificar los prejuicios que Fortran ha adquirido dentro del ámbito de la producción de software. Asimismo se describe detalladamente la implementación de algunas refactorizaciones en Photran, una nueva herramienta gráfica automatizada de refactorización para Fortran.Presentado en el VII Workshop Ingeniería de Software (WIS

Refactorización en código Fortran heredado

Este artículo exhibe los obstáculos hallados por los programadores en las tareas de mantenimiento de software heredado escrito en Fortran. Por un lado se se~nalan las dificultades que se presentan en los procesos de comprensión, adaptación y mejora de este tipo de software. Por otro lado se encuadra una solución a este problema proponiendo la refactorización como técnica para ser aplicada en dichos procesos, intentando además, desmitificar los prejuicios que Fortran ha adquirido dentro del ámbito de la producción de software. Asimismo se describe detalladamente la implementación de algunas refactorizaciones en Photran, una nueva herramienta gráfica automatizada de refactorización para Fortran.Presentado en el VII Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI

Performance-Driven Interface Contract Enforcement for Scientific Components

Several performance-driven approaches to selectively enforce interface contracts for scientific components are investigated. The goal is to facilitate debugging deployed applications built from plug-and-play components while keeping the cost of enforcement within acceptable overhead limits. This paper describes a study of global enforcement using a priori execution cost estimates obtained from traces. Thirteen trials are formed from five, single-component programs. Enforcement experiments conducted using twenty-three enforcement policies are used to determine the nature of exercised contracts and the impact of a variety of sampling strategies. Performance-driven enforcement appears to be best suited to programs that exercise moderately expensive contracts