Web服务器基于不精确响应的Web服务机制

传统Web服务器对于到达的请求使用先来先服务机制.但是,先来先服务机制无法为到达的请求提供区分服务和服务质量保证.在不精确计算和弱.硬实时调度策略基础上,提出了一种Web服务质量机制(简称WQS)为到达Web服务器的请求提供区分服务与服务质量保证.WQS不同于先来先服务机制在于:它首先利用一个请求分类器分类到达的请求到不同级别的队列.其次,借助不精确调度器与内容自适应器,WQS能够使优先级高的队列中请求具有好的响应率和短的响应延迟,使优先级低的队列中请求具有满意的响应率和可接受的响应延迟.最后,本论文描述了一系列在ApacheWeb服务器上针对.WQS的仿真实验,实验表明:WQS是一种能够提供区分服务与服务质量保证,达到改进传统Web服务器或Web服务的可行和有效的方法.

An Imprecise Response Service Mechanism Based on Differentiated Service for Web Server

The traditional Web server handles incoming requests by using first-come first-served mechanism. However, first-come first-served mechanism cannot provide differentiated service and guaranteed quality of service for incoming requests. A kind of Web Quality of Service (WQS) mechanism was proposed based on imprecise computation method and weakly-hard real-time scheduling policy to provide differentiated service and guaranteed quality of service for incoming requests in Web servers. Unlike first-come first-served mechanism, the WQS first made use of a request classifier to classify incomingrequests into different level queues. Then, by means of an imprecise scheduler and a content adaptor, the WQS could make requests in high priority queues to have good response rate and short response delay and could make common requests in low priority queues to have satisfactory response rate and acceptable response delay. Finally, a series of simulating experiments for the WQS in Apache Web server was described. The experiments show that the WQS is a feasible and effective method to provide differentiated service and guaranteed quality of service for improving traditional Web server or Web services.