When complete, the Crossroads supercomputer at Los Alamos National Laboratory (LANL) is expected to deliver quadruple the performance of LANL’s already-powerful Trinity supercomputer (20.16 Linpack petaflops). Now, the first phase of Crossroads – called “Tycho” – has been successfully installed at the lab, with the lab calling it a “stepping stone” to the larger system and hailing it as the first large-scale deployment of Intel’s new Sapphire Rapids CPUs.

As one of the labs operating under the umbrella of the National Nuclear Security Administration (NNSA), LANL plays its supercomputer specs and workloads a bit closer to the chest. That said: the full Crossroads system, based on HPE’s Cray EX liquid-cooled supercomputer, will use Intel’s Sapphire Rapids with high-bandwidth memory (HBM). Tycho, meanwhile, consists of 2,600 nodes based on Sapphire Rapids processors with more traditional DDR memory. LANL also said that Tycho’s filesystem, for the first time in the lab’s supercomputing history, will comprise entirely solid-state drives.

With this news, Tycho now represents the first (public) large-scale deployment of Intel’s delayed Sapphire Rapids CPUs, which also recently shipped to Argonne National Laboratory for use in its forthcoming exascale Aurora system. Aurora’s nodes will be upgraded to the HBM-equipped Sapphire Rapids, but LANL told HPCwire that Tycho’s nodes will retain their DDR configuration.

In the announcement, LANL staff said that testing was bearing out their expectations for Crossroads’ eventual power.

“We’re excited to be entering this new phase of supercomputing at the Lab,” said Jim Lujan, program director for HPC platforms at LANL. “Early benchmarks indicate a four-times increase in speed over Trinity. All of the new efficiencies that are part of Tycho, and ultimately Crossroads, come together to reduce that crucial time to insight. Improving efficiencies in many areas for modeling and simulation is what this project is all about.”

Tycho represents a bit of a branding departure for the lab’s systems, as well. Befitting LANL’s role in the NNSA, Trinity and Crossroads are both named after nuclear weapons test series; Tycho, meanwhile, is named after a spacecraft from popular sci-fi show The Expanse. Tycho will be accompanied by Rocinante and Razorback, other “key Crossroads components” that are also named after ships from The Expanse. In an email to HPCwire, Lujan explained that Rocinante is “roughly a 1/5 sized version of Crossroads” that operates in an unclassified environment and is used for application development and testing; Razorback, meanwhile, is a “very small system” serving as a software development testbed and a venue for “reproducing issues seen on the larger systems of Crossroads and Tycho in order to collaborate with vendor support on potential resolutions.”

Now, with Tycho freshly installed, work will turn to stabilizing the system, with the aim of classified use by the end of 2022 and full production in March of next year. Until the HBM portion of Crossroads is deployed, Tycho will serve the three NNSA labs; after full deployment, Tycho will transition to other workloads for the Advanced Simulation and Computing (ASC) program. The full system is slated for production readiness in September of 2023. Crossroads is intended to help ensure that the nation’s nuclear weapon stockpile is “safe, secure and reliable.”

Header image: the installation of Tycho’s 8,000-pound cabinets. Image courtesy of LANL.