Yasushi Negishi

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Torus networks are commonly used for massively parallel computers, its performance often becomes the constraint on total application performance. Especially in an asymmetric torus network, network traffic along the longest axis is the performance bottleneck for all-to-all communication, so that it is important to schedule the longest-axis traffic smoothly.(More)
High productivity is critical in harnessing the power of high-performance computing systems to solve science and engineering problems. It is a challenge to bridge the gap between the hardware complexity and the software limitations. Despite significant progress in programming language, compiler, and performance tools, tuning an application remains largely a(More)
Simultaneous Multi-Thread (SMT) techniques are becoming popular because they increase the efficiency of CPU resource usage by allowing multiple threads to run on a single physical processor at a very fine granularity. Emerging real-time applications, however, may not benefit from the SMT techniques because those techniques often compromise the predictable(More)
To optimize various high performance computing (HPC) programs on complex supercomputer architectures source-to-source optimization tools are becoming important to support network-architecture-specific and application-specific performance optimization in addition to compiler optimizations. Because of try-and-error nature of performance optimization work and(More)
Video on demand (VOD) systems are becoming popular. They have special requirements for receiving VOD data steadily, but common general communication protocols cannot meet their requirements. Several new protocols have been designed to ful ll this service requirement, but it takes a long time for a protocol to be supported from end to end. We propose a VOD(More)
Multicore processors are becoming dominant in the high performance computing (HPC) area, so multithread programming with OpenMP is becoming a key to good performance on such processors, though debugging problems remain. In particular, it is difficult to detect data races among threads with nondeterministic results, thus calling for tools to detect data(More)
Video o n demand (VOD) sys t ems are becoming popular. T h e y have special requirements for receiving VOD data steadily, but c o m m o n general communicat ion protocols canno t m e e t the ir requirements. Several n e w protocols have been designed t o fulfill th i s service requirem e n t , bu t it takes a long t i m e f o r a protocol t o be supported f(More)
UPC is designed to improve user productivity when programming distributed-memory machines. Yet the shared-memory abstraction also makes performance analysis hard as it introduces extra overhead with local accesses and implicit communication with remote ones. As far as we know, there are no mature software utilities for systematic analysis and tuning of(More)