Priority and Dependency-Based DAG Tasks Offloading in Fog/Edge Collaborative Environment

Fog computing is a decentralized computing infrastructure in which data, compute, storage and applications are located somewhere between the data source and the cloud. It usually adopts convenient and flexible distributed services, which can realize low-cost and real-time data analysis and intelligent control. Efficient communication and fog/edge collaboration have become popular research issues. In this paper, the offloading problem of dependent tasks in fog/edge collaborative environment is studied. Dependent task is modeled as a directed acyclic graph (DAG), and the scenario that fog nodes are configured with heterogeneous multi-core servers is considered. According to task dependencies and energy consumption requirements, all subtasks executed on different edge devices are prioritized, and the Priority and Dependency-based DAG Tasks Offloading Algorithm (PDAGTO) is proposed. Simulation results have shown that, compared with the existing work, the proposed algorithm can effectively reduce the average delay and the total energy consumption of during the procedure of task offloading.