Lawrence Berkeley National Laboratory

Exascale supercomputers are first-of-their-kind instruments with potentially paradigm-shifting capabilities. However, enabling complex applications at scale and high performance can be difficult, requiring hard work and deep technical understanding. Specific programming models are often needed to achieve the desired performance, and, early on, systems are undergoing debugging and rapid development. This makes it challenging to run on new systems quickly following their deployment. The Application Integration (AppInt) area of the Exascale Computing Project was designed to be the integration point between applications, supporting software, system environments, high-performance computing facilities, and vendors. We describe how the AppInt team addressed these challenges while also promoting the use of portable and sustainable programming models and helping harden systems prior to general availability.