一种有资源适应性的transcoding代理缓存机制

A Resource-Adaptive Transcoding Proxy Caching Mechanism

在基于transcoding代理的流媒体服务系统中,CPU和网络是两种潜在的瓶颈资源.本文提出了一种有资源适应性的transcoding代理缓存机制,统一考虑CPU和网络的资源需求,以提高系统的服务能力.首先推导了多版本缓存策略下网络收益和CPU收益的计算方法.通过引入一个时变的影响因子α(t),给出了缓存系统聚合资源收益的表达.在此基础上给出了单个对象的缓存价值函数,并设计了RAC替换算法.实验表明RAC具有较好的资源适应性和系统吞吐率.

In the transcoding proxy based streaming media systems, CPU and network are potential bottleneck resources. In this paper, a resource-adaptive transcoding proxy caching mechanism is proposed, which deals with network and CPU demand in an integrated fashion and aims to improve the systems capability potentially. We first explore the network gain and CPU gain of caching multiple versions at the same time. By introducing a time-vary influence factor （t） ,the aggregated resource gain of the caching system is derived. Then,we derive the merit function of caching a single object under a given caching status, and design the RAC cache replacement algorithm. The experimental result shows that RAC can achieve good resource-awareness and improved system throughput.