Proportional Delay Guarantee in Web QoS Based on Predictive Control

As the heterogeneity of Web clients increasing, the differentiated service becomes an important issue for e-commerce Web sites, and the control theory has already been used for this in Web server. However, when workloads vary significantly, the real-time performance of feedback control needs to be improved. After analyzing the heavy-tailed property of embedded files in Web pages, this paper presents a predictive approach based on the queuing feature of Web server and HTTP 1.1 persistent connections. It achieves the relative delay guarantee by calculating the future delay of different priorities and adjusting their quota of service threads. The experimental results demonstrate that the proposed approach performs a better dynamic property.