A Japanese supercomputer took the world title for the fastest computer in the world after the latest TOP500 list was announced Monday morning at the International Supercomputing Conference in Hamburg, Germany. Fujitsu's K Computer, powered by the latest SPARC64 VIIIfx CPUs and the "Tofu" interconnect, delivered a world beating 8.162 petaflops on the Linpack benchmark, vaulting over the now second-place 2.57 petaflop Tianhe-1A supercomputer in China and third-place 1.76 petaflop Jaguar supercomputer in the US.

The last Japanese supercomputer that topped the TOP500 list was the Earth Simulator, which held the number one spot from 2002 to 2004. That system, by the way, delivered 35 teraflops, which doesn't even rate a place on the current list.
 
As of today, the current top 10 supers are:

1. 8.16 petaflops, K computer, Japan
2. 2.57 petaflops, Tianhe-1A, China
3. 1.76 petaflops, Jaguar, United States
4. 1.27 petaflops, Nebulae, China
5. 1.19 petaflops, TSUBAME 2.0, Japan
6. 1.11 petaflops, Cielo, United States
7. 1.08 petaflops, Pleiades, United States
8. 1.05 petaflops, Hopper, United States
9. 1.05 petaflops, Tera-100, France
10. 1.04 petaflops, Roadrunner, United States

That's right, all of the top 10 systems are now a petaflop or more, and the first machine that cracked the petaflop mark in 2006, IBM's Roadrunner supercomputer, has been pushed into the number 10 spot.

Unlike in years past when IBM and Cray dominated these top systems, today there's a much greater degree of vendor parity.  Beside the two aforementioned supercomputer makers, Fujitsu, HP, NEC, SGI, Dawning, and Bull all claim at least one of these petaflop systems. The big surprise, of course, is Fujitsu. Long absent from the top ten, the Japan-based computer maker has made a spectacular comeback with the K deployment. 

The K Computer (short for called Kei Soku Keisanki) has had a tumultuous history. The system is the result of Japan's Next-Generation Supercomputing Project, an effort led by RIKEN, a government-backed research agency. Initially the project was a joint venture involving NEC, Hitachi, and Fujitsu, with the original design mixing NEC vector processors with Fujitsu scalar ones. In 2009, NEC and Hitachi backed out of the contract, leaving Fujitsu as the lone system vendor. Subsequently, the Japanese government considered pulling the plug on the project, but later reinstated most of the funding.

The final K system set for completion in 2012 is spec'd for 10 petaflops, so one can assume that we'll see that upgrade over the next year. Nevertheless, even in its unfinished state, the K system is quite impressive. Not only is the machine more than three times as powerful, FLOPS-wise, as the number two GPU-powered Tianhe-1A, but it is even more energy efficient, delivering over 8 Linpack petaflops with less than 10 megawatts of power. That's almost as energy-efficient as the other power-sipping Japanese petaflop supercomputer, the GPU-accelerated TSUBAME 2.0 machine.

The exceptional energy efficiency of K is provided courtesy of the 8-core SPARC64 VIIIfx processor, a 58 watt chip that delivers 128 peak gigaflops. That's nearly up to the standards of an HPC-style GPU, a processor which basically does nothing but FLOPS. For comparison, an IBM Power7 CPU provides about 256 gigaflops, but consumes 200 watts, while IBM's other HPC chip, the PowerPC A2 SoC used in Blue Gene/Q looks to be around twice as energy-efficient as the current crop of GPUs.

In any case, don't expect SPARC64 VIIIfx systems to start populating the TOP500 list (or any list) in force. This is a specialty chip, even more so now, thanks to Oracle's abandonment of Sun Microsystems' supercomputing business. It does, however, demonstrate that purpose-built CPUs can deliver performance-per-watt efficiencies on par with GPUs for high performance computing.

Also, don't expect the K Computer to stake out the number one spot for very long. It will almost certainly not enjoy the two-year reign the Earth Simulator did in 2002. NCSA's Power7-based Blue Waters system is slated to hit the 10-petaflop mark when it's installed later 2011 and Lawrence Livermore National Lab's Blue Gene/Q Sequoia supercomputer is aiming for 20 petaflops when fully deployed in 2012.  Also on the drawing board is the GPU-accelerated OLCF-3 system at Oak Ridge National Lab, which is expected to deliver between 10 to 20 petaflops. And China certainly has plans to build systems in the 10-petaflop range and beyond.

Speaking of which, even though China's top super got out-Linpacked this time around, the country continues to fill up TOP500 slots at a breakneck pace. The nation now has 62 supercomputers on the list, up from just 24 a year ago. As a result, China has more top machines than Germany and the UK combined, and greater than any nation except for the US. Despite that, the US still owns more than half the total systems (256) on the list. But depending upon what Asia and Europe deploy over the next six months, the number of US-based supercomputers on the TOP500 could conceivably slide below the 50 percent mark by the time the next TOP500 list comes out in November.