Almost 2,500 high-performance computing boffins have descended upon the German city of Hamburg to attend the International Supercomputing Conference 2012 (ISC) this week to discuss the latest and greatest innovations and applications in the realm of supercomputing. The biggest news of ISC, by far, is that the USA has beaten back the Chinese and Japanese to reclaim pole position on the 39th Top500 list — the list of the world’s fastest supercomputers. In retaliation, China is now promising to deliver a 100-petaflops by 2015 — some two years before the rest of the world is expected to reach such lofty computational heights.
The world’s fastest supercomputer is now Sequoia, an IBM Blue Gene/Q installation at the Lawrence Livermore National Laboratory in California, primarily for use by the National Nuclear Security Administration. The system’s Linpack benchmark performance is 16.32 petaflops (16 quadrillion floating point operations per second), some 55% faster than the Japanese K, the previous record holder. The Sequoia’s theoretical max performance is just over 20 petaflops. Sequoia will be used to simulate the safety and efficacy of the US nuclear weapons stockpile, without the need for actual underground testing — and other scientific research.
Under the hood, Sequoia boasts 98,304 18-core processors and 1.6 petabytes of RAM, spread out amongst 96 racks that occupy a total floorspace of 3,000 square feet (280 square meters). Compute Node Linux powers around 97,500 of the processors, and Red Hat Enterprise Linux runs on 768 I/O (filesystem) nodes. The Blue Gene/Q chip itself is a terrifying 1.6GHz 64-bit PowerPC A2, which is 4-way simultaneously multithreaded, with each core harboring a SIMD quad-vector double precision floating point unit. There are 18 cores in total, but one core is a backup in case another is permanently damaged, and another handles interrupts, asynchronous I/O, and other operating system helper functions. The chip is theoretically capable of 205 gigaflops while drawing 55 watts — just a wee bit more efficient than desktop PC chips.
The chip’s frugal power consumption means that Sequoia uses only 7.9 megawatts of power while running Linpack, or around two gigaflops per watt. This is enough to put Sequoia at the top of the Green500 list of most efficient supercomputers. In comparison,the K supercomputer uses 12.6 megawatts to perform 10.5 petaflops — or only 800 megaflops per watt. An Ivy Bridge Core i7-3770K achieves around 50 gigaflops while consuming around 100 watts — or 500 megaflops per watt.
Back in 2010, the 2.5-petaflops Tianhe-1A became the first Chinese installation to reach the top of the Top500, knocking the 1.7-petaflops Cray XT5 Jaguar supercomputer at the US Oak Ridge National Laboratory down into second place. This in itself was enough to get US alarm bells ringing — the US has basically been the undisputed king of supercomputing, except for a short period in the ’90s — and then Japan turned on the K computer at the RIKEN institute. K was four times faster than Tianhe and 6 times faster than Jaguar. The US has been in second place a few times throughout the years, but third place? Unthinkable!
Judging by the rumblings being made by the director of China’s National Supercomputing Center, though, perhaps America should get used to this being a three horse race. Speaking to The Register, Liu Guangming says that China will power up a 100-petaflops supercomputer sometime in 2015. This is rather impressive, as previous estimates have centered around the 2017-2018 mark.
Guangming says his team is currently evaluating what architecture the supercomputer will use. It could use Intel Xeons (like the Tianhe-1A), AMD Opterons, or its own homegrown CPUs. As we’ve reported previously, China has already built a 1-petaflops computer from its domestic 16-core 64-bit ShenWei CPUs. The Chinese also have to decide on whether the 100-petaflops computer will be a CPU-GPU hybrid (like Tianhe, which uses 7,168 Nvidia Tesla GPUs) or a straight-up CPU-powered beast. Again, Guangming says that they might use homegrown GPUs — though he didn’t share any details on their specs.
Back at home, the next big American supercomputer will be the Cray XK6 Titan, Jaguar’s successor. Titan, built out of AMD Opterons and Nvidia Kepler GPUs, should have a peak performance of 24 petaflops. You can see on Top500 that the upgrade process has already begun!
In other news, IBM’s SuperMUC, installed in Munich, Germany took fourth place on the Top500 and became the fastest supercomputer in Europe. SuperMUC is novel because it uses a hot water cooling system to reduce its power consumption by 40%.