Contention-aware workflow scheduling on heterogeneous computing systems with shared buses

Heterogeneous computing systems (HCSs), which balance performance and efficiency by leveraging diverse computation resources, are widely used for executing workflow applications. These computation resources are typically interconnected through shared buses. When multiple participants simultaneously transmit data, communication contention arises, leading to longer communication time than expected. Nevertheless, the contention issue for the shared bus is rarely investigated in the literature. This paper proposes a Contention-Aware Clustering-based List scheduling (CACL) method to effectively address workflow scheduling in shared bus-based HCSs. In CACL, tasks are grouped into clusters based on criticality, clusters are mapped to computation resources, and then all tasks and edges in the workflow are scheduled to computation and communication resources in the HCS. Experimental results on realistic workflows demonstrate that CACL effectively addresses the communication contention issue, and reduces scheduling length by 5%–25% compared to existing methods, making it a robust solution for workflow scheduling in shared-bus-based HCSs.