The PRACE Scientific Steering Committee has selected “Lattice-CSC: Optimizing & Building an Efficient Supercomputer for Lattice-QCD & to Achieve First Place in Green500,” as this year’s winning paper. The paper was submitted by postdoctoral researcher Dr. David Rohr and his colleagues, Matthias Bach, Gvozden Neskovic, Volker Lindenstruth, Christopher Pinke and Owe Philipsen. Rohr and his cohorts are from the Department of HPC Architecture of the Frankfurt Institute for Advanced Studies, at the University of Frankfurt.
The PRACE award committee evaluated all papers to determine if they met any of the following criteria: a breakthrough in science achieved through high performance computing, an algorithm or implementation that achieves a significant improvement in scalability or performance, or a novel approach to performance evaluation on a massively parallel architecture. In this paper, the Frankfurt University team outlined the challenges of energy-efficient supercomputers and presented an implementation to minimize power consumption. The system, known as the L-CSC cluster, was built from commodity hardware components and is specifically targeted to run Lattice QCD simulations.
The cluster features a multi-GPU design, with four AMD FirePro S9150 GPUs per node, providing 320 GB/second of memory bandwidth and 2.6 TFLOPS of peak performance. The high bandwidth makes it well suited for memory-bound Lattice QCD computations, while the GPU-heavy design ensures excellent energy efficiency.
In November 2014, the L-CSC cluster captured the top spot on the Green500 list with 5,270 MFLOPS/Watt for the Linpack benchmark. The paper presents Linpack optimizations the researchers developed, in addition to other power efficiency improvements, which helped L-CSC reach the record-breaking benchmark. The authors also present an overview of the Lattice QCD application on L-CSC.