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Dona Crawford
Associate Director for Computation

Livermore’s Three-Pronged Strategy for High-Performance Computing

IN 1995, the Advanced Simulation and Computing (ASC) Program (originally the Accelerated Strategic Computing Initiative, or ASCI) was formed as a critical element of the Stockpile Stewardship Program. ASC’s purpose is to accelerate the development of the simulation capabilities needed to analyze the performance, safety, and reliability of nuclear weapons.
At the beginning of the ASC Program, we looked at the kinds of problems we would need to solve, when we needed to be able to solve them, and how quickly we would need to get calculation results back. This analysis determined the size of the computers we set out to acquire through partnerships with computer industry leaders. Our goal was to obtain a a computer system by 2004 that could process 100 trillion floating point operations per second (teraflops). In the past 8 years, Livermore, Los Alamos, and Sandia—the three national laboratories involved in ASC—have fielded a number of increasingly powerful massively parallel scalable supercomputers, that is, large numbers of processors working together on complex calculations. ASCI Purple, arriving at Livermore next year, will be the fulfillment of the original ASC 100-teraflops goal. But the story does not end there.
As the supercomputers came on board, researchers in stockpile stewardship and other programs developed increasingly complex codes to take advantage of them. One-dimensional codes gave way to two- and three-dimensional codes, and some science simulations were developed based on first-principles physics. Users needed more from the supercomputers—more capability to run scientific calculations at large scale and more capacity to simultaneously handle multiple calculations and diverse workloads. As our users’ needs have evolved, so has our strategy as described in the article entitled Riding the Waves of Supercomputing Technology.
In brief, our strategy is to work with the U.S. supercomputer industry to pursue three technology curves, separately and at times in tandem. The three curves are current scalable multiprocessor technology, open-source (nonproprietary) cluster technology, and cell-based (computer-on-a-chip) technology. The goal is to deliver platforms best suited to the work at hand. The supercomputing industry has chosen to pursue massively parallel scalable architectures, and it is spending billions of dollars exploring technologies in this arena. We work with these companies to leverage their advances and investments, bringing more capability and capacity cost-effectively to our users. We are constantly on the lookout for “what’s next” and what’s “after next” to meet future workloads. Our goal is to find an affordable path to the petaflops (1,000 teraflops) level for the ASC Program by 2010—beating the speed of Moore’s Law (capacity doubling every 18 months) not just by a little but by a lot.
Today’s ASC Program uses proven and mature technologies, because there’s no room for risk in system functionality and reliability when simulating on tight programmatic schedules the behavior of nuclear weapons. To determine our next-generation supercomputer, we have been investigating machines featuring open-source cluster technology. This technology is the basis of our recently deployed Multiprogrammatic Capability Resource (MCR) machine, which is being used by Laboratory researchers who can tolerate some problems with functionality as we work out the bugs and add features for a production environment. In preparation for what’s after that, we are researching technology that’s farther out on the horizon—cell-based supercomputers. Assuming that budgets and the technology hold, we will acquire such a cell-based machine, BlueGene/L, in late 2004 or early 2005. BlueGene/L will be used to improve physics models in ASC codes and to evaluate the technology for suitability to a broader workload.
This is our strategy for staying ahead of Moore’s Law—a strategy that is absolutely crucial to the Laboratory. Here at Livermore, we have a culture that supports and embraces simulation, which, with experimentation and theory, forms the scientific discovery process. A successful simulation environment requires more than a huge computer with maximum peak speeds. It requires code development, physics models, code validation, and an infrastructure—storage systems, visualization capabilities, networks, compilers, debuggers—all working together. We must balance all these factors to maintain a computing environment that has the power, capability, and capacity to serve the Laboratory’s needs in stockpile stewardship, energy and environment, biotechnology and bioresearch, chemistry and material science, and more.
Pursuing three technology curves—what’s current, what’s next, and what’s after next—and working with U.S. industry to bring the technologies to the nation’s critical missions is Livermore’s computing strategy. This three-pronged strategy allows us to deliver robust production-level computing to meet today’s programmatic needs while looking ahead to provide for the demands of tomorrow.

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UCRL-52000-03-6 | June 25, 2003