Integrated performance monitoring of client/server software

This paper presents an integrated software monitoring system for distributed programs based on the client/server mechanism. It allows the identification of performance bottlenecks due to shortcomings in both hardware and software. As opposed to other approaches, the proposed system is not limited to an isolated view of the application, but rather allows the monitoring of its behavior in a live environment. Being able to reveal interaction with other applications such as competition for resources, it can more clearly identify, where a client/server application experiences unnecessary delay. It thereby fills the gap left by the lack of integrated monitoring systems for client/server applications and constitutes a first step towards alleviation of user frustration caused by overly long response times. Performance debugging is accomplished both by source code instrumentation and by network and host monitoring. A graphical analysis tool allows for various views that facilitate the identification of possible deficiencies in various parts of a system which may cause poor response. The abilities of the monitor are demonstrated by means of an instrumented Apache Web server. The comprehensive information provided by the monitoring system enables well-founded decisions for software and hardware reconfiguration, thus avoiding the cost intensive replacement of components in an all encompassing manner.