Performance Analysis of an Asynchronous Web Server

Concurrency can be implemented in a Web server using synchronous and asynchronous mechanisms offered by the underlying operating system. Compared to the synchronous mechanisms, the asynchronous mechanisms are attractive because they provide the benefit of concurrency while alleviating much of the overhead and complexity of multithreading. The proactor pattern in middleware, which effectively encapsulates the asynchronous mechanisms supported by the operating system, can be used to implement a high performance Web server. In this paper, we present a queuing model of an asynchronous Web server implemented using the proactor pattern. We then describe a decomposition strategy to enable the application of the model in practical scenarios. We demonstrate the use of the model to guide configuration and provisioning decisions with several examples