Sensitivity Analysis of Combined Software and Hardware Performance Models: Open Queueing Networks

Contemporary approaches to software performance engineering su er from weak integration with the design process and provide little feedback to developers. An approach to software performance modelling is presented, based on annotating design speci cations with performance parameters and operational analysis of queueing networks representing the hardware. Analytical sensitivity analysis is provided to 1) point out where model re nement and parameter capture e ort should be focused, and 2) suggest optimisations in the design speci cation. Sensitivities are obtained by di erentiation of the combined software (workload) and hardware performance model. Only open queueing networks are considered at the hardware level. The results are validated, and it is pointed out that further work is particularly needed in the areas of dynamic software performance modelling and distributed systems.