Proactive Task Offloading for Load Balancing in Iterative Applications

Abstract

Load imbalance is often a challenge for applications in parallel systems. Static cost models and pre-partitioning algorithms distribute the load at the beginning. Nevertheless, dynamic changes during execution or inaccurate cost indicators may lead to imbalance at runtime. Reactive work-stealing strategies can help monitor the execution and perform task migration to balance the load. However, the benefits depend on migration overhead and assumption about future execution.Our proactive approach further improves existing solutions by applying machine learning to online load prediction. Following that, we propose a fully distributed algorithm for adapting the prediction result to guide task offloading. The experiments are performed with an artificial test case and a realistic application named Sam(oa)$$^2$$ 2 on three systems with different communication overhead. Our results confirm improvements for important use cases compared to previous solutions. Furthermore, this approach can support co-scheduling tasks across multiple applications.