Wu Feng
Virginia Tech College of Engineering
The newly released Green500 List shows a continuing rapid improvement in environmentally friendly supercomputers around the world, according to Wu Feng, list founder and Virginia Tech associate professor of computer science and electrical and computer engineering at Virginia Tech’s College of Engineering.
“Of the Top 10 greenest supercomputers in the world, two trends toward greener supercomputing are emerging: one is aggregating many low-power processors such asIBM’s BlueGene/Q and the K Computer by Fujitsu at the RIKEN Advanced Institute for Computational Science, and the other trend is using energy-efficient accelerators, typically from the gaming/graphics market to complement the commodity central processing units from Intel and Advanced Micro Devices,” Feng said.
The Green500 has ranked the energy efficiency of the world’s 500 fastest supercomputers since its debut in 2007, serving as a complement to the well-known supercomputer industry marker TOP500. The list was founded by Feng and Kirk W. Cameron, associate professor of computer science. The Green500 measures energy efficiency using a metric defined as millions of floating-point operations per second divided by watts, or MFLOPS/W. The list is released twice a year, in June and in November.
“The Green500 seeks to raise awareness in the energy efficiency of supercomputing, and in turn, drive energy efficiency as a first-order design constraint – one that is on par with performance or speed,” said Feng.
As in the November 2010 edition, an IBM Blue Gene/Q prototype supercomputer tops this edition of the Green500. However, the Blue Gene/Q prototype that tops this list – the Blue Gene/Q Prototype 2 -- differs from the one that topped the previous list -- Blue Gene/Q Prototype 1 -- in that the former delivers significantly better performance, but with the same number of processor cores and only a marginal increase in power consumption. The result is a 2,097 MFLOPS/W rating, the first supercomputer to surpass the 2,000 MFLOPS/W bar, according to Feng. Coming in at No. 6 on the Green500 list is the world’s fastest supercomputer, the K supercomputer from RIKEN in Japan. It also aggregates many low-power processors and is one of the greenest supercomputers in the world.
Among accelerator-based supercomputers, the greenest in the world is the DEGIMA Cluster, a self-built supercomputer from Nagasaki University in Japan. The DEGIMA Cluster is accelerated by Advanced Micro Devices /ATI Technologies Inc.’s Radeon graphics processing units (GPUs) on a thrifty supercomputing budget of approximately $500,000. Six additional accelerator-based machines round out the 10 greenest supercomputers in the world, three with GPU accelerators --including two from NVIDIA Corp. and one more from AMD/ATI -- and three with cell-based accelerators from IBM.
During the past six months, the average efficiency of measured systems on the Green500 has increased to 256 MFLOPS/W from 230 MFLOPSW, an improvement of 11 percent, Feng said. Additionally, the efficiency of the greenest supercomputer in the world improved by 25 percent to 2097 MFLOPS/W from 1684 MFLOPS/W, while the efficiency of accelerator-based systems on the Green500 has been just as dramatic, improving 23 percent to 707 MFLOPS/W from 573 MFLOPS/W.
“Seventy percent of the 20 greenest supercomputers are now accelerator-based,” Feng said, adding that such a statistic would have been unlikely when the Green500 List started four years ago.
The Green500 List is a grassroots venture, relying on sponsorships and individual contributions from volunteer staff comprised of Feng, Cameron and graduate students at the Virginia Tech College of Engineering. Serving as the present title sponsor for the Green500 is Supermicro Computer Inc.