Four supercomputers at Oak Ridge computing complex among world's 25 fastest

Jaguar XT5 Cray machine remains fastest, most versatile for open science: Jaguar XT5, a Cray high-performance computing system component at the Department of Energy's Oak Ridge National Laboratory, remains the world's fastest supercomputer for unclassified research, according to a roster released this week in Hamburg. The TOP500 list named four machines at the ORNL computing complex among the world's 25 swiftest. All told, five Oak Ridge machines made the list.

"Researchers from national laboratories, universities, and industry harness Jaguar's supercomputing capability to solve some of the toughest science and engineering problems in the world," said Jeff Nichols, interim associate laboratory director for ORNL's Computing and Computational Sciences Directorate. "Today dozens of large-scale, computationally-intensive research projects run on Jaguar. The XT5 is often the scientific community's fastest, and sometimes only way to find solutions to grand challenges in climate change, nanoscience, and the energy technology needs in renewable energy, bioenergy, nuclear energy, and fusion energy."

Today's scientific grand challenges are too complex for soloists to solve, and simulations help teams explore complex, dynamic scenarios. "The successes of the Jaguar XT5 and the four other Oak Ridge supercomputers that made the TOP500 list highlight the critical mass of talent we have here," said Arthur Bland, project director of ORNL's Leadership Computing Facility to support science of critical importance to the nation with the most advanced computational capabilities available. The Leadership Computing Facility is sited at the National Center for Computational Sciences at ORNL, which UT-Battelle manages for DOE.

Twice a year, the TOP500 list (www.top500.org) ranks high-performance computing systems on their speed in running High-Performance Linpack, a software code that solves a dense matrix of linear algebra equations. Only two machines have reached calculating speeds exceeding the petaflops range of a quadrillion floating point operations per second.

With a peak speed of 1.382 petaflops, Jaguar XT5 ranked No. 2 on the TOP500 list. The XT5 is part of a larger Cray system, also called Jaguar, that includes a 263-teraflops (trillion floating point operations per second) XT4 component that ranked number 12.

Another Oak Ridge machine making the TOP500 is Kraken, an XT5 component of a Cray system belonging to the National Institute for Computational Sciences and the University of Tennessee. Kraken XT5 ranked No. 6 to become the world's fastest academic machine. The other Oak Ridge machines to make the list are the NICS-UT XT4 component, called Athena and ranked number 21, and the NCCS's Eugene, an IBM Blue Gene/P system that ranked number 247.

In 2008 Jaguar was a 263-teraflops Cray XT4. It was upgraded with the addition of a 1.4 petaflops Cray XT5 component in the fall. An InfiniBand network connects Jaguar's components for faster data production. With approximately 182,000 AMD Opteron processing cores, the combined system can calculate at a peak rate of 1.64 petaflops. If each person on Earth could perform one mathematical calculation per second, it would take more than 650 years of nonstop work to accomplish what Jaguar XT4/XT5 can in a day.

"The Jaguar system helps the scientific community gain insight into topics critical to DOE and the nation, such as mitigating and adapting to climate change, making efficient photovoltaic materials, producing next-generation biofuels, and controlling plasma in a fusion reactor," said NCCS Director James Hack.

Such simulations have run hundreds of millions of processor hours on the Jaguar system, Bland said.

By a thin margin, Jaguar XT5 trailed the top-ranked machine on the TOP500 list, Roadrunner, a DOE supercomputer at Los Alamos National Laboratory that became the world's first petascale supercomputer in June 2008. Classified simulations on Roadrunner help assure the safety, security, and reliability of America's nuclear weapons stockpile.

In contrast, Jaguar is serving the diverse demands of unclassified science applications. Such codes and algorithms explore topics including batteries, combustion, carbon capture and storage, medicine, nanotechnology, astrophysics, aeronautical engineering, groundwater, and fundamental physics. Balancing superlative speed with impressive memory, Jaguar XT5 in November ran the fastest scientific application ever, sustaining more than a petaflops in a simulation of superconductors and earning the prestigious Gordon Bell Prize.

DOE's Office of Science (SC), the largest supporter of basic research in the physical sciences in the United States, provides high-performance computing resources to the scientific community. Its leadership computing facilities at Oak Ridge and Argonne national laboratories, supported by SC's Office of Advanced Scientific Computing Research, make large awards of supercomputing time to researchers through the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program. In 2009 approximately 470 million processor hours were allocated on Jaguar. In 2010, to further accelerate transformational research, the allocation will increase to 700 million processor hours.