The tests evaluated single processor performance, the parallel scaling of OpenMP, MPI, and MLP, as well as interference effects in large throughput scenarios. NASA reported that the SGI Altix system performed well on all tests, and yielded significant per-processor performance gains while maintaining scalability.
"The results we've been seeing are extraordinary for 256 processors," said James Taft, president of Sienna Software, Inc. and currently a consultant at NASA Ames. "For instance, the OVERFLOW CFD application has generated 200 GFLOPS of sustained performance with 256 processors, which is exactly twice the performance that NASA Ames team achieved with the first 128-processor Altix system - all without optimizing application code."
NASA sought to implement a 256-processor shared-memory system because many key production codes have been optimized to run on such systems. Researchers reported that running their codes on a 256-processor shared-memory system has allowed the facility to see immediate scalability benefits with little or no porting or tuning. The Altix family of servers combines industry-standard 64-bit Linux with the Intel® Itanium® 2 processor family and SGI® NUMAflex™ architecture to enable global shared memory systems from a few to hundreds of processors, which is a first for Linux OS-based computing. Powered by the third-generation NUMAflex supercomputing architecture, even the largest data sets can be handled and analyzed with ease and in record time. Only the SGI Altix 3000 family of servers is designed around this scalable shared-memory architecture that analyzes data sets as whole entities, without breaking them up into smaller segments to be handled by individual processors. The Altix architecture has proven ideal both for complex shared-memory applications running on a large single system image, and for communication-intensive applications optimized for clustering.
"Clearly, the economic environment for large-scale systems continues to force designers to amortize as much R&D as possible from broader horizontal markets. Now we have one company integrating and creating the system memory interconnect, another providing the processing elements, and the open-source community providing a substantial part of the system software," said Bob Ciotti, lead for the Tera-scale Application Group at NASA Ames. "This type of arrangement is resulting in systems that are highly competitive in price and performance for large-scale computation."