The race for the fastest supercomputer

The United States’ supercomputing standing has eroded, but that could change soon.

The top slot in the latest list of the 500 fastest supercomputers released this month is held by the Sunway TaihuLight in China’s National Supercomputing Center in Wuxi. The Sunway TaihuLight has held the No. 1 spot in the last four semi-annual rankings and is significantly more powerful than the other systems on the list, according to Jack Dongarra, a professor at University of Tennessee, Knoxville, who has an appointment at Oak Ridge National Lab and helped created the list.

“If you add up the [petaflops of the] next five machines -- numbers two through six -- then it’s equal to the No. 1 machine,” Dongarra said.

Sunway TaihuLight, which has more than 10 million cores and over a million GB in memory, reached 93,014.6 TFlop/s on the Linpack performance test. It was built by the National Research Center of Parallel Computer Engineering & Technology and uses Chinese-developed ShenWei processors rather than the Intel, IBM or NVIDIA processors used in most other supercomputers.

The U.S. has the fewest machines it's had on the global list of high-performance computers since the Top500 rankings began 25 years ago. Titan, the country's highest-ranked supercomputer, rose only to number five. But a pair of new machines set to go online next year could place America back in the top spots, experts say.

Dona Crawford, a retired associate director of computation at Lawrence Livermore National Lab, said the United States was dethroned for the first time by Japan in 2002 with its Earth Simulator.

Historically, “the hands-down leader in supercomputing has been the United States,” Crawford told GCN. “So when Japan came out of the blue … people stood up, took notice."

After Earth Simulator came online, federal R&D policymakers expressed concerns over the fact that Japan seemed to be pulling ahead in high-performance computing.  The Department of Energy's then-Secretary Spencer Abraham announced the U.S. would build the world's fastest computer and awarded Oak Ridge National Lab a $25 million grant to start development.

China’s dominance on the recent lists indicates it is investing heavily in high-performance computing as supercomputers become a vital tool for simulating everything from nuclear explosions to medicine.

“Today, science is really driven by simulation and computers do that simulation for us,” Dongarra said. More recently, the machines also have been used for artificial intelligence and machine learning.

China's rise on the list has also been relatively recent, Dongarra said. The country had no supercomputers in 2001, “and over the last 16 years they have increased, developed and funded high-performance computing so that today they have the most,” he said

“The U.S. [HPC] ecosystem is still the strongest in the world,” Crawford said. But China may be "better poised to maintain and sustain" the lead because of its long-term commitment to building an HPC environment.  

Sharon Hays, an account manager for systems integrator CSRA Inc., said the Top500 list provides valuable insight into global trends. The company worked with the National Institutes of Health on its Biowulf Cluster, which ranked 66th on this list.

“It’s an important metric in measuring not only individual supercomputers, but … in understanding international competitiveness in the high performance computing arena,” Hays said.

The Top500 list is not a perfect ranking of high performance computers, however.

First off, there are supercomputers not on this list, Hays said. Machines used by the intelligence community, for example, wouldn’t be measured. And while the list gives a general idea of the computer’s power, it doesn’t tell you how well it can run specific applications.

The way United States computers have held up on the list, though, has been impressive, Crawford said.

“Oak Ridge is No. 5 in the list, but that computer is five years old,” she said. “Livermore is sixth on the list, that computer is six years old, which is unprecedented in most computer time frames. …They turn over every three to five years because something bigger, better, badder comes along.”

The two new DOE supercomputers -- one at ORNL and one at LLNL -- will likely put the United States back atop the list, Dongarra predicted.

The Oak Ridge Summit and Lawrence Livermore Sierra supercomputers are expected to go online before the June Top500 list is released, and they’ll be running both the IBM Power 9 and Nvidia Volta V100 processors. Argonne National Lab is expected to get an exascale system in 2021, too.

“You ain’t seen nothing yet,” Crawford said. “We are just at the very beginning. When you look at artificial intelligence, machine learning and big data, which seem to be in the news all the time now, by this wonderful tool called supercomputing … the world’s going to be very different 10 years from now.”

Editor's note: This article was changed Dec. 1 to correct the spelling of Sharon Hays' name.