Response time analysis of a middleware event demultiplexing pattern for network services

Society is becoming increasingly reliant on the services provided by distributed, performance sensitive software systems. These systems demand multiple simultaneous quality of service (QoS) properties. A key enabler in recent successes in the development of such systems has been middleware, which comprises reusable building blocks. Typically, a large number of configuration options are available for each building block when composing a system end-to-end. The choice of the building blocks and their configuration options have an impact on the performance of the services provided by the systems. Currently, the effect of these choices can be determined only very late in the lifecycle, which can be detrimental to system development costs and schedules. In order to enable the right design choices, a systematic methodology to analyze the performance of these systems at design time is necessary. Such a methodology may consist of models to analyze the performance of individual building blocks comprising the middleware and the composition of these building blocks. As a first step towards building this methodology, this paper introduces a model of the reactor pattern, which provides important synchronous demultiplexing and dispatching capabilities to network services and applications. The model is based on the stochastic reward net (SRN) modeling paradigm. We illustrate how the model could be used to obtain the response time of a virtual private network (VPN) service provided by a virtual router (VR)