基于TTE的改进加权轮询调度算法

在时间触发以太网(TTE)中,TT消息优先级最高,RC消息只能在TT消息调度的离散时间片内传输,因此,TT消息离线调度表的设计会对RC消息调度产生一定影响。针对这一问题,提出了基于最优时间片的改进加权轮询(MWRR)调度算法。首先,通过TT消息约束条件限制获得TT消息离线调度表,进而得到保证RC消息较大资源利用率的时间片信息;其次,在离散时间片对不同类型RC消息进行调度,并运用网络演算方法对其最坏端到端延迟进行分析;最后,通过实验仿真证实了本文算法不仅具有较低的复杂度和较好的公平性,保证了实际应用中算法的可行性,而且在时延性方面均优于先到先得(FIFO)、优先级(PQ)和加权轮询(WRR)调度算法。

A modified weighted round robin scheduling algorithm in TTE

TT messages that have the top priority among three kinds of traffics affect RC message communication inevitably in time-triggered Ethernet (TTE).Therefore,RC messages have to be scheduled among discrete time slices caused by TT message offline schedule table.A modified weighted round robin (MWRR)scheduling method based on optimal time slice was proposed in this paper.Firstly,TT message offline schedule table was calculated satisfying the requirements of TT message constraints in order to get optimal time resources for RC flow transmission;secondly,different kinds of RC flows were scheduled in several time slices and the worst end to end delays were analyzed by network calculus in TTE;finally,experiments show that MWRR algorithm in the paper not only has low complexity,good fairness and feasibility in practical application,but also obtains better real-time performance than first input first output (FIFO),priority queue (PQ)and weighted round robin (WRR) scheduling algorithm.