保障QoS的实时Linux系统设计

The design of real-time Linux for guaranteeing QoS

为了在综合业务网络中保障实时多媒体业务的服务质量(QoS),设计了软实时Linux系统。系统中将网络接受中断的推后执行工作校由工作队列来执行,而非传统的由网络接受软中断处理。工作队列是Linux2.6内核的进程调度机制,对实时多媒体任务和数据任务实施不同的优先级调度,以保证实时多媒体任务的优先处理而不是尽力而为(BestEffort),保障其服务质量。通过简单的测试证明本系统运行稳定,能够保障实时多媒体业务的服务质量,尤其对解决延迟抖动问题有明显的效果。

For guaranteeing Quality of Service of real-time multimedia task in the integrative business network,a soft real-time Linux system was designed.In this system,the deferring work of receiving interrupt in network shall be executed by work queue,but not the receiving soft-interrupt in network,which is traditional.Work queue is a new kind of bottom halves in Linux 2.6 kernel.It is the most difference from soft-interrupt that deferring work shall be executed in process context.Thus,under the mechanism of process scheduling in Linux 2.6 kernel,the real-time multimedia task and data task shall be scheduled with different priority.This will guarantee the prior handling for real-time multimedia task but not Best Effort and QoS of it.A simple test has been done to certify that the system is stable,and it can guarantee the QoS of real-time multimedia task,especially the delay jitter.