异构系统双关键级分布式功能的动态调度

Dynamic Scheduling of Dual-Criticality Distributed Functionalities on Heterogeneous Systems

异构分布式嵌入式系统是由多种不同关键级功能组成的混合关键级系统,且每个功能又是由多个具有优先级约束的任务组成的分布式功能.异构分布式嵌入式系统的混合关键级调度在性能与时间约束上面临严重的冲突.如何提高系统总体性能,并仍然确保高关键级功能的实时性,在性能与实时性上取得合理的权衡则成为研究的主要优化问题.提出公平策略的动态双关键级任务调度算法F_DDHEFT(fairness on dynamic dual-criticality heterogeneous earliest finish time)以提高系统的整体性能;提出关键级策略的动态双关键级任务调度算法C_DDHEFT(criticality on dynamic dual-criticality heterogeneous earliest finish time)以满足高关键级功能的实时性;提出时限时距策略的动态双关键级任务调度算法D_DDHEFT(deadline-span on dynamic dual-criticality heterogeneous earliest finish time),在满足高关键级功能实时性的基础上,提高系统的整体性能,最终在性能与时间约束上取得合理的权衡.实例分析和实验结果验证了D_DDHEFT算法的优越性.

Heterogeneous distributed systems are mixed-criticality systems consisting of multiple functionalities with different criticality levels. A distributed functionality contains multiple precedence-constrained tasks.Mixed-criticality scheduling of heterogeneous distributed systems faces severe conflicts between performance and time constraints.Improving the overall performance of systems while still meeting the deadlines of higher-criticality functionalities,and making a reasonable tradeoff between performance and timing are major optimization problems.The F_DDHEFT（fairness of dynamic dual-criticality heterogeneous earliest finish time）algorithm is to improve the performance of systems.The C_DDHEFT（criticality of dynamic dual-criticality heterogeneous earliest finish time）algorithm is to meet the deadlines of higher-criticality functionalities.The D_DDHEFT（deadline-span of dynamic dual-criticality heterogeneous earliest finish time）algorithm is to allow the lower-criticality functionalities to be processed positively for better overall performance while still meeting the deadlines of higher-criticality functionalities,such that a reasonable tradeoff between performance and timing is made. Both example and extensive experimental evaluation demonstrate significant improvement of the D_DDHEFT algorithm.