HPC for Energy researchers attended the 25th Euromicro International Conference on Parallel, Distributed and Network-Based Processing (PDP 2017) that took place in St. Petersburg (Russia) from the 6 to the 8 of March. Two papers were presented in the main track of the programme:
- Zanon Boito, F., Bez, J. L., Dupros, F., Dantas, M. A. R., Navaux, P. O. A., Aochi, H., "High Performance I/O for Seismic Wave Propagation Simulations".
This paper describes our research to provide high performance I/O for seismic wave propagation simulations. Earthquake early warning systems are designed to provide near real-time prediction of strong ground motion. Such systems are crucial tools for risk mitigation and disaster prevention. The ability to accurately and quickly simulate the propagation of seismic waves in complex media lies at the heart of such systems. Besides the processing requirements, it is important for seismic simulations to leverage a high-performance storage infrastructure to output results as frequently as possible, so they can be used for the decision-making process. We propose and evaluate a series of I/O optimizations to the Ondes3D seismic wave propagation simulation, considering its different types of output files separately. These optimizations are designed while keeping the previous output formats, in order not to compromise the application interaction with the other parts of the earthquake early warning system. The optimization techniques presented in this paper have provided I/O performance improvements of up to 85% and decreased the application execution time up to 70%.
- Bez, J.L., Zanon Boito, F., Schnorr, L.M., Navaux, P. O. A., Mehaut, J.F., "TWINS: Server Access Coordination in the I/O Forwarding Layer".
This paper presents a study of I/O scheduling techniques applied to the I/O forwarding layer. In high-performance computing environments, applications rely on parallel file systems (PFS) to obtain good I/O performance even when handling large amounts of data. To alleviate the concurrency caused by thousands of nodes accessing a significantly smaller number of PFS servers, intermediate I/O nodes are typically applied between processing nodes and the file system. Each intermediate node forwards requests from multiple clients to the system, a setup which gives this component the opportunity to perform optimizations like I/O scheduling. We evaluate scheduling techniques that improve spatiality and request size of the access patterns. We show they are only partially effective because the access pattern is not the main factor for read performance in the I/O forwarding layer. A new scheduling algorithm, TWINS, is presented to coordinate the access of intermediate I/O nodes to the data servers. Our proposal decreases concurrency at the data servers, a factor previously proven to negatively affect performance. The proposed algorithm is able to improve read performance from shared files by up to 28% over other scheduling algorithms and by up to 50% over not forwarding I/O.
Euromicro is an international scientific organization advancing sciences and applications of Information Technology and Microelectronics. A major focus is on organizing conferences and workshops in Computer Science and Computer Engineering. As explained in the conference website, Parallel, Distributed, and Network-Based Processing has undergone impressive change over recent years. New architectures and applications have rapidly become the central focus of the discipline. These changes are often a result of cross-fertilisation of parallel and distributed technologies with other rapidly evolving technologies. It is of paramount importance to review and assess these new developments in comparison with recent research achievements in the well-established areas of parallel and distributed computing, from industry and the scientific community. PDP 2017 provides a forum for the presentation of these and other issues through original research presentations and facilitates the exchange of knowledge and new ideas at the highest technical level.
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