TiNy threads on BlueGene/P: Exploring many-core parallelisms beyond The traditional OS

Operating Systems have been considered as a cornerstone of the modern computer system, and the conventional operating system model targets computers designed around the sequential execution model. However, with the rapid progress of the multi-core/manycore technologies, we argue that OSes must be adapted to the underlying hardware platform to fully exploit parallelism. To illustrate this, our paper reports a study on how to perform such an adaptation for the IBM BlueGene/P multi-core system. This paper´s major contributions are threefold. First, we have proposed a strategy to isolate the traditional OS functions to a single core of the BG/P multi-core chip, leaving the management of the remaining cores to a runtime software that is optimized to realize the parallel semantics of the user application according to a parallel program execution model. Second, we have ported the TNT (TiNy Thread) execution model to allow for further utilization of the BG/P compute cores. Finally, we have expanded the design framework described above to a multi-chip system designed for scalability to a large number of chips. An implementation of our method has been completed on the Surveyor BG/P machine operated by Argonne National Laboratory. Our experimental results provide insight into the strengths of this approach: (1) The performance of the TNT thread system shows comparable speedup to that of Pthreads running on the same hardware; (2) The distributed shared memory operates at 95% of the experimental peak performance of the machine, with distance between nodes not being a sensitive factor; (3) The cost of thread creation shows a linear relationship as threads increase; (4) The cost of waiting at a barrier is constant and independent of the number of threads involved.