Ikki Fujiwara

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—As the scales of supercomputers increase total cable length becomes enormous, e.g., up to thousands of kilometers. Recent high-radix switches with dozens of ports make switch layout and system packaging more complex. In this study, we study the optimization of the physical layout of topologies of switches on a machine room floor with the goal of reducing(More)
—As the scales of parallel applications and platforms increase the negative impact of communication latencies on performance becomes large. Random network topologies can be used to achieve low hop counts between nodes and thus low latency. However, random topologies lead to increased aggregate cable length and cable packaging complexity on a machine room(More)
—In this paper, we demonstrate that we can reduce the communication latency significantly by inserting a fraction of randomness into a wireless 3D NoC (where CMOS wireless links are used for vertical inter-chip communication) when considering the physical constraints of the 3D design space. Towards this end, we consider two cases, namely 1) replacing(More)
Market-based resource allocation is expected to be an effective mechanism to allocate resources in a cloud computing environment, where the resources are virtualized and delivered to users as services. In this paper we propose a market mechanism to efficiently allocate multiple computation/storage services among multiple participants. The proposed mechanism(More)
— Network bandwidth is a performance concern especially for collective communication because the bisection bandwidth of recent supercomputers is far less than their full bisection bandwidth. In this context we propose to exploit the use of a network coding technique to reduce the number of unicasts and the size of transferred data generated by(More)
—Low communication latency becomes a main concern in highly parallel computers and supercomputers. Random network topologies are best to achieve low average shortest path length and low diameter in hop counts between nodes and thus low communication latency. However, random topologies lead to a problem of increased aggregate cable length on a machine room(More)
—With low-delay switches on the horizon, end-to-end latency in large-scale High Performance Computing (HPC) interconnects will be dominated by cable delays. In this context we define a new network topology, Skywalk, for deploying low-latency interconnects in upcoming HPC systems. Skywalk uses randomness to achieve low latency, but does so in a way that(More)
Acknowledgements My time as a graduate student at SOKENDAI and NII has been supported by many kind people. This page attempts to recognize those who have been most helpful along the way. First of all, I am deeply indebted to my supervisor, Professor Dr. Kento Aida. His advice, support and kind encouragement on both professional and private issues have(More)