China’s Tianhe-1A is being recognized as the world’s fastest supercomputer. It has 7168 NVIDIA Tesla GPUs and achieved a Linpack score of 2.507 petaflops, a 40% speedup over Oak Ridge National Lab’s Jaguar, the previous top machine. Today’s WSJ has an article,

“Supercomputers are massive machines that help tackle the toughest scientific problems, including simulating commercial products like new drugs as well as defense-related applications such as weapons design and breaking codes. The field has long been led by U.S. technology companies and national laboratories, which operate systems that have consistently topped lists of the fastest machines in the world.

But Nvidia says the new system in Tianjin—which is being formally announced Thursday at an event in China—was able to reach 2.5 petaflops. That is a measure of calculating speed ordinarily translated into a thousand trillion operations per second. It is more than 40% higher than the mark set last June by a system called Jaguar at Oak Ridge National Laboratory that previously stood at No. 1 on a twice-yearly ranking of the 500 fastest supercomputers.”

The NYT and HPCwire also have good overview articles. The HPC article points out that the Tianhe-1A has a relatively low Linpack efficiency compaed to the Jaguar.

“Although the Linpack performance is a stunning 2.5 petaflops, the system left a lot of potential FLOPS in the machine. Its peak performance is 4.7 petaflops, yielding a Linpack efficiency of just over 50 percent. To date, this is a rather typical Linpack yield for GPGPU-accelerated supers. Because the GPUs are stuck on the relatively slow PCIe bus, the overhead of sending calculations to the graphics processors chews up quite a few cycles on both the CPUs and GPUs. By contrast, the CPU-only Jaguar has a Linpack/peak efficiency of 75 percent. Even so, Tianhe-1A draws just 4 megawatts of power, while Jaguar uses nearly 7 megawatts and yields 30 percent less Linpack.

The (unofficial) “official” list of the fastest supercomputers is TOP500 which seems to be inaccessible at the moment, due no doubt to the heavy load caused by the news stories above. The TOP500 list is due for a refresh next month.