Multigrain parallel processing on compiler cooperative chip multiprocessor

This paper describes multigrain parallel processing on a compiler cooperative chip multiprocessor. The multigrain parallel processing hierarchically exploits multiple grains of parallelism such as coarse grain task parallelism, loop iteration level parallelism and statement level near-fine grain parallelism. The chip multiprocessor has been designed to attain high effective performance, cost effectiveness and high software productivity by supporting the optimizations of the multigrain parallelizing compiler, which is developed by Japanese Millennium Project IT21 "Advance Parallelizing Compiler". To achieve full potential of multigrain parallel processing, the chip multiprocessor integrates simple single-issue processors having distributed shared data memory for both optimal use of data locality and scalar data transfer, local data memory for processor private data, in addition to centralized shared memory for shared data among processors. This paper focuses on the scalability of the chip multiprocessor having up to eight processors on a chip by exploiting of the multigrain parallelism from SPECfp95 programs. When microSPARC like the simple processor core is used under assumption of 90 nm technology and 2.8 GHz, the evaluation results show the speedups for eight processors and four processors reach 7.1 and 3.9, respectively. Similarly, when 400 MHz is assumed for embedded usage, the speedups reach 7.8 and 4.0, respectively.