Emerging Computational Architectures
Fall 2007 Lecture Series

Presented by...
The Architecture and Compilers Group
Computer and Information Sciences Department
University of Pennsylvania

Ubiquitous Compute Acceleration
Lars Nyland
Senior Architect, NVIDIA Corporation
Wu & Chen Auditorium, 3-4pm
Tuesday, November 27th


In this talk, I will cover three topics: 1) The G80 architecture, 2) The CUDA programming language, and 3) and recent work on N-Body simulation. The G80 architecture supports both graphics and non-graphics computation, using an array of custom processors on a single chip. The programming model is neither SIMD nor MIMD, but somewhere in between, where we can exploit the advantages of each. The current performance part has 128 processors running at 1.3 - 1.5 GHz. With dual-issue capabilities, this places the peak performance near 500 GFLOPS. CUDA is the C programming language with a few extensions for programming the G80. These include thread launch/terminate, synchronization, sharing, and atomic operations.

In a collaborative effort with Jan Prins (UNC CS) and Mark Harris (NVIDIA), we have written an N-Body simulator using CUDA that runs on NVIDIA hardware. We achieve a sustained computational rate of 210 GFLOPS, or 16k bodies interacting at nearly 30 steps/second. This is substantially faster than a conventional CPU, as the core of the computation relies on 1/sqrt(x), a optimized function on the G80, as it is required in graphics (and physics) for normalizing vectors. I'll summarize with thoughts about the availability of accelerated computing.


Lars Nyland is a senior architect in the "compute" group at NVIDIA, where he designs, develops and tests architectural features to support non-traditional uses of graphics processors. Prior to joining NVIDIA, Lars was an associate professor of computer science at the Colorado School of Mines in Golden, Colorado. He ran the Thunder Graphics Lab, where demanding computational applications were coupled with immersive, 3D graphics. Between Lars' PhD and his position in Colorado, he was a member of the research faculty at UNC, Chapel Hill. Some notable achievements were the development of the DeltaSphere scene digitizer and its use at Monticello to provide an immersive experience for visitors to the New Orleans Museum of Art's "Jefferson and Napoleon" exhibit. He also spent considerable time studying N-Body algorithms, parallelism of N-Body algorithms for Molecular Dynamics, and parallel programming languages. Lars earned his PhD at Duke University in 1991 under the direction of John Reif, exploring high-level parallel programming languages.

Organized by Milo Martin and Amir Roth

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