To meet increasing QoS requirements of Web applications it is vital to design an efficient Web server. This article describes a pipeline server architecture, which can get intra-request parallelism. Based on control theory, we adopt predictor and feedback control methods to allocate threads of each stage dynamically. As a result, server can satisfy variant workloads adaptively. With the help of these ideas, we implement a novel kernel web server, KETA. Experiment results prove that KETA is an efficient kernel Web server with high performance.