Achieving Computational I/O Efficiency in a High Performance Cluster Using Multicore Processors ∗

Cluster computing has become one of the most popular platforms for high-performance computing today. The recent popularity of multicore processors provides a flexible way to increase the computational capability of clusters. Although the system performance may improve with multicore processors in a cluster, I/O requests initiated by multiple cores may saturate the I/O bus, and furthermore increase the latency by issuing multiple non-contiguous disk accesses. In this paper, we propose an asymmetric collective I/O for multicore processors to improve multiple non-contiguous accesses. In our configuration, one core in each multicore processor is designated as the coordinator, and others serve as computing cores. The coordinator is responsible for aggregating I/O operations from computing cores and submitting a contiguous request. The coordinator allocates contiguous memory buffers on behalf of other cores to avoid redundant data copies