Luna Supercomputer Providing Compute Cycles for LANL Directed Stockpile Work

Luna, the newest TLCC2 supercomputer at LANL, went into production use by the DSW Program in April 2012.

Luna, the newest Tri-Lab Capacity Cluster (TLCC2) supercomputer deployed at Los Alamos National Laboratory, is providing much needed compute cycles for the Directed Stockpile Work (DSW) Program, including the B61 Life Extension Program. Local integration and security testing, as well as approvals from the DOE Los Alamos Site Office were completed in April 2012, two weeks earlier than planned.

Luna augments the existing ASC TLCC1 capacity platforms at LANL: Typhoon (106 TFlop/s) and Hurricane (51 TFlops/s) and allowed Redtail (71 TFlops/s) to be retired. Luna is based on Appro's Xtreme-X™ Supercomputers which uses the Intel® Xeon E5 processor. It has a total of 24,640 processors for a combined peak capability of 539.1 TFlop/s.

Users and developers are seeing speedups of factors of 2–4 on typical calculations compared with previous production machines such as Hurricane and Typhoon. Because of excellent scaling on Luna, users can use more processors for a calculation compared with previous production machines and achieve even higher speedups. "Luna is such a well-balanced machine that it is changing the way we work," says LANL user Jas. Mercer-Smith. He continues, "Problems that used to take 3 weeks can now be completed in a few days."

The code developer perspective is also positive. Lagrangian Applications Project developer Rob Ward notes, "The performance improvements in Luna have allowed us to turn around our testing much faster."

The speedup is thought to be due to the faster Luna interconnect and on-board hardware improvements. Such speedups mean that users can get faster turnaround on their calculations and/or run with higher fidelity thus improving efficiency and/or results. This will be particularly advantageous for weapons safety calculations at LANL.

(LA-UR 12-21969)