Semi-Static and Dynamic Load Balancing for Asynchronous Hurricane Storm Surge Simulations
Maximilian Bremer, John Bachan, Cy P. Chan · 2018
The performance of hurricane storm surge simulations is critical to forecast and mitigate the deadly effects of hurricane landfall. Supercomputers play a key role to run these simulations quickly; however, disruptive changes in future computer architectures will require adapting simulators to maintain high performance, such as increasing asynchrony and improving load balance. We introduce two new multi-constraint, fully asynchronous load balancers and a new discrete-event simulator (DGSim) that is able to natively model the execution of task-based hurricane simulations based on efficient one-sided, active message-based communication protocols. We calibrate and validate DGSim, use it to compare the algorithms' load balancing capabilities and task migration costs under many parameterizations, saving of over 5,000x core-hours compared to running the application code directly. Our load balancing algorithms achieve a performance improvement of up to 56 percent over the original static balancer and up to 97 percent of the optimal speed-up.