Abstract
In 2011, Oak Ridge National Laboratory began an upgrade to Jaguar to convert it from a Cray XT5 to a Cray XK6 system named Titan. This is being accomplished in two phases. The first phase, completed in early 2012, replaced all of the XT5 compute blades with XK6 compute blades, and replaced the SeaStar interconnect with Cray’s new Gemini network. Each compute node is configured with an AMD Opteron™ 6274 16-core processors and 32 gigabytes of DDR3-1600 SDRAM. The system aggregate includes 600 terabytes of system memory. In addition, the first phase includes 960 NVIDIA X2090 Tesla processors. In the second phase, ORNL will add NVIDIA’s next generation Tesla processors to increase the combined system peak performance to over 20 PFLOPS. This paper describes the Titan system, the upgrade process from Jaguar to Titan, and the challenges of developing a programming strategy and programming environment for the system. We present initial results of application performance on XK6 nodes.
