Towards runtime optimization of software quality based on feedback control theory

The increasingly complex environments in which software systems are running today have made runtime software quality unstable and hardly in an optimal state, especially for those systems in open and dynamic environments, e.g. Internetware. In this paper, we explore the effectiveness of software cybernetics and feedback control theory in runtime software quality optimization. We propose a method of runtime quality optimization by using feedback control theory. Specially, we consider the problem of runtime optimization for a specific quality attribute, namely throughput, for Web-based systems. We design a double-layer feedback control model for the problem and implement the runtime optimization control method. In the method, runtime feedbacks are collected and used by the control model to adjust related control parameters. The experimental study has demonstrated the effectiveness of software cybernetics and feedback control theory in runtime quality optimization.