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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Design and Implementation of a Scalable Membership Service for Supercomputer Resiliency-Aware Runtime

As HPC systems and applications get bigger and more complex, we are approaching an era in which resiliency and run-time elasticity concerns be- come paramount.We offer a building block for an alternative resiliency approach in which computations will be able to make progress while components fail, in addition to enabling a dynamic set of nodes throughout a computation lifetime. The core of our solution is a hierarchical scalable membership service provid- ing eventual consistency semantics. An attribute replication service is used for hierarchy organization, and is exposed to external applications. Our solution is based on P2P technologies and provides resiliency and elastic runtime support at ultra large scales. Resulting middleware is general purpose while exploiting HPC platform unique features and architecture. We have implemented and tested this system on BlueGene/P with Linux, and using worst-case analysis, evaluated the service scalability as effective for up to 1M nodes.

Tock, Yoav↗
DOE OSTI2014

Application-specific I/O Optimizations on Petascale Supercomputers

Data-intensive science frontiers and challenges are emerg ing as computer technology has evolved substantially. Large-scale simu lations demand significant I/O workload, and as a result the I/O performance often becomes a bottleneck preventing high performance in scientific applications. In this paper we introduce a variety of I/O optimization techniques developed and imple mented when scaling a seismic application to petascale. These techniques include file system striping, data aggreg ation, reader/writer limit ing and less interleaving of data, collective MPI-IO, and data staging. The optimizations result in nearly perfect scalability of the target applicat ion on some of the most advanced petascale systems. The techniques introduced in this paper are applicab le to other scientific applications facing similar petascale I/O challenges.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

A uGNI-based Asynchronous Message-driven Runtime System for Cray Supercomputers with Gemini Interconnect

Gemini, the network for the new Cray XE/XK systems, features low latency, high bandwidth and strong scalability. Its hardware support for remote direct memory access enables efficient implementation of the global address space programming languages. Although the user Generic Network Interface (uGNI) provides a low-level interface for Gemini with support to the message-passing programming model (MPI), it remains challenging to port alternative programming models with scalable performance. CHARM++ is an object-oriented message-driven programming model. Its applications have been shown to scale up to the full Jaguar Cray XT machine. In this paper, we present an implementation of this programming model on uGNI for the Cray XE/XK systems. Several techniques are presented to exploit the uGNI capabilites by reducing memory copy and registration overhead, taking advantage of the persistent communication, and improving intra-node communication. Our microbenchmark results demonstrate that the uGNI-based runtime system outperforms the MPI-based implementation by up to 50% in terms of message latency. For communication intensive applications such as N-Queens, this implementation scales up to 15, 360 cores of a Cray XE6 machine and is 70% faster than the MPI-based implementation. In molecular dynamics application NAMD, the performance is also considerably improved by as much as 18%.

Computer Science↗
DOE OSTI2022

Learning to Scale the Summit: AI for Science on a Leadership Supercomputer

The Summit system at Oak Ridge National Lab-oratory (ORNL) has been the world's top AI for science su-percomputer for several years, ranked world's fastest computer at its 2018 launch and currently top system in the US and #2 on the TOP5OO list. Summit's purposeful design to handle both conventional modeling and simulation science and emerging AI workloads has made it a leading destination for AI-powered computational science. We report here on AI for science usage on Summit near the midpoint of its lifespan. We review AI usage across the many science projects that have used Summit. We then examine in detail a set of applications scaling AI to full system as well as projects implementing AI-coordinated science discovery workflows on Summit. Finally, we offer some observations regarding the future of advancing scientific knowledge and understanding via AI, especially in the context of leadership-class scientific computing.

Joubert, Wayne↗
DOE OSTI2024

A Perspective on Scalable AI on High-Performance Computing and Leadership Class Supercomputing Facilities [Industrial and Governmental Activities]

Many scientific applications that support the mission of the US Department of Energy (US-DoE) require modeling complex engineering and/or physical systems. Here, examples of such complex systems arise from: (a) materials science to develop new compounds with exceptional mechanical and thermodynamical properties (e.g., resistance to mechanical stresses and high temperatures), (b) structural and nuclear engineering to model the temporal evolution of the structural damage of concrete shields exposed to continuous neutron and gamma radiations emitted by the nuclear reactor core, (c) urban sciences (e.g., transportation and smart buildings), and (d) power grid systems.

97 MATHEMATICS AND COMPUTING↗