【摘要】 Linux 是目前广泛用于路由设备中的操作系统,而流量管理是这种网络操作系统的一个重要功能.研究了 Linux 系统的流量管理机制,发现当前 Linux 系统所采用的在网络接口的出口实现的基于网络包调度的流量管理机制缺乏对于网络带宽在系统范围的全局性的管理,也缺乏对于输入流的网络处理的有效管理和调度,从而造成不必要的 CPU 资源的浪费.为解决这一问题,提出了一种新颖的网络带宽管理机制,它通过调度网络协议处理所占用的 CPU 时间来实现带宽管理.这种新的机制将网络带宽的管理和调度从网络接口的出口点转移到处理接收到的网络包的系统软件中断处理程序中,从而克服了原来的流量管理机制的缺点.通过系统实现和对比实验,发现该机制本身给系统带来的负载小于 Linux 原来的流量管理机制,同时可以提供更好的流量隔离,并且能够有效地节省用于网络处理的 CPU 资源.更多还原

【Abstract】 Linux is widely adopted in routers nowadays, and traffic control is one of the most important functions for this kind of network-oriented operating systems. This paper studies the traffic control mechanism of Linux system and shows that the packet scheduling based traffic control mechanism adopted by current Linux kernel lacks a global view of system bandwidth, and is also short of efficient ingress scheduling. This can result in unnecessary CPU time wasting. To address this problem, a novel traffic control scheme is proposed, which is based on the CPU scheduling of the network protocol processing. By transplanting packet scheduling from the egress point of network interfaces to the soft interrupt handler that processes incoming packets, the new method can eliminate disadvantages of the old traffic control scheme without introducing any additional demerits. An implementation of the new traffic control scheme is given, and comparative experimental results show that the new mechanism has fewer overload than the old traffic control scheme in Linux, and can maintain the efficiency of traffic isolation and traffic policing while avoiding the CPU time wasting.更多还原