WFQ与WRR调度算法的性能分析与改进

不同类别的业务对时延及时延抖动的要求是不同的,为了满足不同业务的服务质量(QoS),选择一种合适的队列调度算法至关重要. 研究了分组长度对WRR及WFQ算法公平性以及时延性能的影响,并提出了一种基于分组长度及队列权重的改进型WRR算法——enhanced-WRR. 仿真结果表明,当分组长度相同时,WRR与WFQ的时延性能几乎一致;当分组长度不同时,WRR算法不能保证高优先级队列的时延要求,而E-WRR算法的时延性能逼近WFQ算法,能很好地保证高优先级队列的时延要求,并且极大降低了算法复杂度. 

Performance Analysis and Improvement About WFQ and WRR Schedule Algorithm

Different multimedia services have different requirement of delay and jitter, it is essential to select an appropriate schedule algorithm to meet the quality of service (QoS) of different multimedia services. Firstly, the impact on performance of delay and fairness of WRR and WFQ algorithm was studied; then, an enhanced WRR (E-WRR) algorithm based on packet length and queue weight was proposed. Simulation results show that when the packet length in different queues are same, almost same delay performance can be approached by both WRR and WFQ; when the packet length in different queues are different, the delay requirement of higher priority queue cannot be approached with WRR algorithm. However, the delay performance of proposed E-WRR algorithm can be close in upon WFQ algorithm, which can guarantee the delay requirement of higher priority queue, and greatly reduce the calculation complexity of schedule algorithm.