Intra-Tile Parallelization for Two-Level Perfectly Nested Loops With Non-Uniform Dependences

Most important scientific and engineering applications have complex computations or large data. In all these applications, a huge amount of time is consumed by nested loops. Therefore, loops are the main source of the parallelization of scientific and engineering programs. Many parallelizing compilers focus on parallelization of nested loops with uniform dependences, and parallelization of nested loops with non-uniform dependences has not been extensively investigated. This paper addresses the problem of parallelizing two-level nested loops with non-uniform dependences. The aim is to minimize the execution time by improving the load balancing and minimizing the inter-processor communication. We propose a new tiling algorithm, k-StepIntraTiling, using bin packing problem to minimize the execution time. We demonstrate the effectiveness of the proposed method in several experiments. Simulation and experimental results show that the algorithm effectively reduces the total execution time of several benchmarks compared to the other tiling methods.

Program transformations as the base for optimizing parallelizing compilers

В работе рассматриваются преобразования программ, приводящие к ускорению. Приводятся публикации о различных параллельных вычислительных архитектурах и инструментах разработки эффективных программ для них. Рассматривается сочетание распараллеливания и оптимизации доступа к модулям памяти разного уровня. Отмечается, что отставание автоматической оптимизации программ от потребностей новых архитектур сдерживает развитие новых перспективных вычислительных систем. Формулируются задачи развития теории преобразования программ и оптимизирующих (распараллеливающих) компиляторов, которые могли бы привести к существенному повышению производительности труда программистов. Статья обосновывает призыв к модернизации оптимизирующей компиляции.

REVIEW OF PARALLEL TECHNIQUES AND ITS IMPLICATION FOR JAVA

This paper surveys the state-of-the-art parallel techniques for multiprocessor architectures, and studies its implication for Java programs, which are typically compiled at run-time. First, this paper overviews basic techniques of program parallelization in traditional static compilers, followed by a survey of successful parallelizing compilers. Then this paper introduces the latest research topics in this area, particularly focusing on the efforts of combining parallelizing techniques with Java virtual machines, including parallel compilation and parallel real-time garbage collection. Finally, this paper summaries the opportunities and challenges of parallelizing Java computing on multicore platforms.