Staff, hardware shine spotlight on ORNL’s computing capability

Oak Ridge National Laboratory's booth at SC11, held in Seattle, WA.

ORNL was once again a major player at high-performance computing’s (HPC’s) premier conference, SC11, which took place in Seattle, WA from November 12-18. Aside from ORNL’s booth, which hosted a series of talks from experts and researchers representing a range of industry and computational science, the laboratory lent its expertise to numerous other areas throughout the event.

For example, staff members from the OLCF conducted several Birds-of-a-Feather (BoF) sessions for conference attendees. These open engagement discussions have been a staple of the SC conference series for years and are a vital part of the gathering’s educational component. ORNL has consistently contributed and 2011 was no exception, as OLCF staff anchored three BoF sessions over the course of the conference.

Adam Simpson and Anthony DiGirolamo hosted “Heterogeneous supercomputing on ORNL’s Titan,” which examined the programming challenges involved with the GPU/CPU hybrid architecture of Jaguar’s upcoming upgrade, which will see the traditional CPU platform transition to that of a hybrid with the addition of GPUs. The new architecture will make the resulting system capable of a peak speed of 10-20 petaflops, placing it among the ranks of the world’s fastest supercomputers.

Simpson outlined an overview of the hardware and software that will be available on Titan, followed by representatives from CAPS, PGI, and Cray who gave presentations on their GPU compiler directives. In all, roughly 40 people attended, said Simpson, who described the event as “extremely successful.”

And Bobby Whitten, likewise of the OLCF, hosted “HPC Centers,” which provided an open forum for user assistance personnel to discuss topics of interest, which included ticket procedures, queue policies, and organization and structure of support options, to name a few. The goal was to provide an opportunity for user support staff from HPC centers to share ideas and discuss common problems and concerns. “HPC Centers” was an ongoing meeting of the HPC Centers working group, which convenes regularly to discuss user support issues related to supercomputing.

Said Whitten: “This BoF was an important opportunity to gather user support personnel from around the world to share knowledge from their collective experiences. The HPC Centers working group is one of the few organizations that are dedicated to user support topics and is represented by DOE, DoD, NSF, university, international, and industry organizations.”

And finally, the OLCF’s Rebecca Hartman Baker and Judith Hill, along with ORNL’s Samantha Foley, hosted “Developing, Recruiting, and Retaining a Diverse Workforce in HPC,” which presented concrete advice from people who have been successful at recruiting and retaining students, postdocs, and employees from diverse backgrounds. Among other things, the BoF featured a discussion of the challenges that underrepresented minorities face in the HPC workplace, including challenges unique to the field, and examined practices that can be implemented to alleviate those challenges. The panelists, representing academic, industrial, and laboratory HPC workplaces, presented ideas and strategies that have met with success. The session continued with a Q&A and an open discussion.

“In business meetings and at professional conferences and workshops, we often look around the room and find ourselves to be the sole representative of the female half of the population. Our African-American and Latina colleagues report a similar experience. It can be lonely if you are not part of the majority,” wrote the session leaders, along with the OLCF’s Hai Ah Nam, in a recent article in HPCWire (read story at

But it wasn’t only ORNL’s people that shined at SC11. Jaguar, the laboratory’s, and DOE’s, premier supercomputer also received some attention in the HPC Challenge Awards. Jaguar took first runner-up in two of the competition’s four benchmarks, known as High-Performance Linpack (HPL) and STREAM. HPL measures speed by solving a dense linear system of equations, while STREAM measures the memory bandwidth and corresponding computational rate for a simple vector kernel.

In addition, Jaguar took second runner-up in a benchmark known as Global FFT, or Fast Fourier Transform, which evaluates a system’s ability to transform one function into another.

Also on the systems front, three ORNL-based machines landed in the top 20 of the Top500 list, a biannual ranking of the world’s fastest computing systems. The latest list was released at SC11 on November 14. The Department of Energy’s Jaguar, a Cray XT5, ranked number 3; the National Science Foundation’s Kraken, managed by the University of Tennessee and likewise a Cray XT5, came in at number 11; and the National Oceanic and Atmospheric Administration’s Gaea, a Cray XE6, was listed at number 20. All of the systems share ORNL’s state-of-the-art, LEED-certified half acre HPC facility, making the laboratory home to the nation’s most powerful computing complex.

“ORNL’s mission has always been to stand up and support systems that enable scientific breakthroughs,” said Jeff Nichols, ORNL’s associate laboratory director for computing and computational sciences. “While we’re proud of the TOP500 rankings, it is the science that has been achieved on these systems that serves as the true testament to computing at ORNL.”

Besides a major presence in SC’s popular BoF sessions and impressive machine achievements, ORNL featured a number of people on SC11’s conference planning committee. ORNL’s James Rogers served as the technical program executive director and the laboratory’s Becky Verastegui served as conference vice-chair. In all, ORNL had representatives in 22 areas of various committees, including Applications, Tutorials, Broader Engagement, Birds-of-a-Feather, and Posters, to name a few (for a complete list of ORNL’s participating committee members, see

All in all, ORNL’s contributions once again helped to make SC11 high-performance computing’s number one conference and symposium. The same people and hardware that made those contributions are also helping every day to advance a wide spectrum of science and continuing to provide researchers with the tools they need to tackle science’s biggest challenges, from the origins of the universe to climate change to the latest in novel materials.