The latest TOP500 list of the world’s fastest systems was recently published during SC13 and at first glance not much has changed since the previous list released in June. There was only a single new entrant to the top 10, Piz Daint, a Cray XC30 system installed at the Swiss National Supercomputing Centre (CSCS) in Lugano, Switzerland. The same system also holds the title of the most powerful system in Europe.
While on the surface there has not been much list movement, digging a little deeper will uncover some notable trends in how these number-crunchers are achieving their FLOPS magic. For example, the HPC landscape is seeing more and more use of accelerators – highly parallel coprocessors offered by NVIDIA, AMD and Intel.
One of the biggest changes coming down the pike is a new speed test that will offer a more realistic assessment of world’s most performant supercomputers. On Monday, the TOP500 list editors released a new benchmarking scheme, called the High Performance Conjugate Gradient (HPCG).
From the team’s website, “the HPCG Benchmark project is an effort to create a more relevant metric for ranking HPC systems than the High Performance LINPACK (HPL) benchmark, that is currently used by the TOP500 benchmark.”
In a June paper on the HPCG Benchmark, TOP500 list backers Michael Heroux and Jack Dongarra report that the High Performance Linpack (HPL) test is “increasingly unreliable as a true measure of system performance for a growing collection of important science and engineering applications.” The duo observe that designing for good HPL performance can “lead to design choices that are wrong for the real application mix, or add unnecessary components or complexity to the system.”
An interesting aspect of this new benchmark suite is that it will result in a different rating for accelerators and coprocessors that have dominated the TOP500 and Green500 charts lately. These coprocessors only work for a subset of HPC tasks, and the new metric will reflect that.
In a recent interview with HPCwire, Dongarra notes that it’s not time to think about replacing LINPACK just yet. He adds that HPCG will undergo many tweaks over the next couple of years before it’s ready for primetime.
HPCG Benchmark Release 1.0, the first release of the HPCG Suite, is now available for download.