  Beatnik is a novel open source mini-application that exercises the complex
communication patterns often found in production codes but rarely found in
benchmarks or mini-applications. It simulates 3D Raleigh-Taylor instabilities
based on Pandya and Shkoller's Z-Model formulation using the Cabana performance
portability framework. This paper presents both the high-level design and
important implementation details about Beatnik along with four benchmark setups
for evaluating different aspects of HPC communication system performance.
Evaluation results demonstrate both Beatnik's scalability on modern
accelerator-based systems using weak and strong scaling tests up to 1024 GPUs,
along with Beatnik's ability to expose communication challenges in modern
systems and solver libraries.
