Extreme Scaling Workshop at the LRZ.

In July 2013, the Leibniz Supercomputing Centre (LRZ) held the first workshop to test extreme scaling on SuperMUC, the 3 PFLOP/s system with 147,456 Intel Sandy Bridge CPU cores. Groups from 15 international projects came to the LRZ with codes that had already shown scaling up to 4 islands (32,768 cores). During the workshop, the participants could test the scaling capabilities of their codes on the whole system. Application experts from the LRZ, Intel and IBM were on site to resolve issues and assist in the performance optimization. New techniques like fast startup were successfully tested which helped to reduce the startup time by a factor of 2-3. At the end of the workshop, 6 applications were successfully running on the full machine, while the other 8 applications managed to run on half of the system. The LRZ is already planning a follow-up workshop where the improvements and feedback from the experts will be tested. More information available at http://www.lrz.de.