Self-Tuning of Software Systems Through Goal-based Feedback Loop Control

Quality requirements of a software system cannot be optimally met, especially when it is running in an uncertain and changing environment. In principle, a controller at runtime can monitor the change impact on quality requirements of the system, update the expectations and priorities from the environment, and take reasonable actions to improve the overall satisfaction. In practice, however, existing controllers are mostly designed for tuning low-level performance indicators rather than high-level requirements. By linking the overall satisfaction to a business value indicator as feedback, we propose a control theoretic self-tuning method that can dynamically adjust the tradeoff decisions among different quality requirements. A preference-based reasoning algorithm is involved to configure hard goals accordingly to guide the following architecture reconfiguration.