Sierra, Livermore’s next advanced technology high performance computing system, will join LLNL’s lineup of supercomputers in 2017–2018. The new system will provide computational resources that are essential for nuclear weapon scientists to fulfill the National Nuclear Security Administration’s stockpile stewardship mission through simulation in lieu of underground testing. Advanced Simulation and Computing (ASC) Program scientists and engineers will use Sierra to assess the performance of nuclear weapon systems as well as nuclear weapon science and engineering calculations. These calculations are necessary to understand key issues of physics, the knowledge of which later makes its way into the integrated design codes. This work on Sierra has important implications for other global and national challenges such as nonproliferation and counterterrorism.
For Sierra’s installation, the CORAL partnership (Collaboration of Oak Ridge, Argonne, and Livermore) was formed to procure high performance computers from multiple vendors. IBM was selected as the vendor for LLNL. The IBM-built Sierra supercomputer is projected to provide four to six times the sustained performance and five to seven times the workload performance of Sequoia, with a 125 petaFLOP/s peak. At approximately 11 megawatts, Sierra will also be about five times more power efficient than Sequoia. By combining two types of processor chips—IBM’s Power 9 processors and NVIDIA’s Volta graphics processing units (GPUs)—Sierra is designed for more efficient overall operations and is expected to be a promising architecture for extreme-scale computing.
In late 2016, LLNL acquired three small-scale “early access” (EA) versions of Sierra, consisting of IBM Minsky compute nodes with 20 Power 8 cores each and 4 NVIDIA Pascal GPUs. These small systems feature components only one generation behind those of Sierra. EA systems enable application porting and tuning in advance of the CORAL Sierra system delivery and acceptance (late 2017 to mid-2018). To enable this work, beta software co-designed by the CORAL laboratories and IBM is being installed on the EA systems.