Performance engineering - editorial

Imperial College London was host to the 24th Annual UK Performance Engineering Workshop in July 2008. UKPEW is an enjoyable workshop that brings together researchers in the performance engineering community to discuss quantitative aspects of, for instance, Grid computing, web and e-commerce, performance modelling techniques, power management and wireless network performance. In 2008, we had 29 papers presented over the two days of the workshop and this IET Software Special Issue represents significantly extended versions of the best selected papers from that workshop.     

PEPA Queues: Capturing Customer Behaviour in Queueing Networks

Queueing network formalisms are very good at describing the spatial movement of customers, but typically poor at describing how customers change as they move through the network. We present the PEPA Queues formalism, which uses the popular stochastic process algebra PEPA to represent the individual state and behaviour of customers and servers. We offer a formal semantics for PEPA Queues, plus a direct translation to PEPA, allowing access to the existing tools for analysing PEPA models. Finally, we use the ipc/DNAmaca tool-chain to provide passage-time analysis of a dual Web server example.