面向虚拟路由器的基于历史转发开销的资源调度算法

Historical Forwarding Overhead Based the Resource Scheduling Algorithm for the Virtual Router

通过研究以Xen为代表的虚拟工具中资源调度算法,得知它们无法保证虚拟路由器中资源共享的公平性。该文提出一种基于历史转发开销的资源调度算法,用来确保路由器实例占用资源的公平性,尤其物理平台的输入/输出(I/O)资源。该算法通过统计路由器实例最近的报文转发开销来计算出路由器实例调度的优先级,确保平均吞吐量较低的路由器实例获得被调度的机会。同时,该算法通过设置优先级计算公式中处理延迟的值,达到对延迟敏感强的路由器实例的支持,以及通过预测报文处理时间决定待处理报文是否丢弃,避免不必要的系统开销。通过实验测试,相对于Credit算法,该文算法在确保虚拟路由器资源共享的公平性方面存在明显优势,并且能为延迟敏感的路由器实例提供支持。

The current resource scheduling algorithms can not offer promise for the fairness of shared resources based on research on the resource scheduling algorithms in the system virtualization tools represented by Xen. This paper proposes a Historical Forwarding Overhead Based the Resource Scheduling Algorithm （HFOB_RSA） to ensure that router instances occupy determinate physical resources including I/Os that should be proportional to actual requirements. This algorithm can determine the scheduling priority of router instances by calculating the last several forwarding overhead of each router instance to make those router instances with low real throughput have an opportunity for being scheduled. Meanwhile, this algorithm also sets the value of processing delay in priority formula to provide support for those delay-sensitive router instances and determines whether or not to discard the non-disposed packets in advance by forecasting their processing time to avoid the unwanted overhead. The experimental results prove that the HFOB_RSA has superiority over Credit algorithm in terms of the fairness of shared resources in the virtual router. And HFOB_RSA also is able to provide support for the delay-sensitive router instances.