SWIM: An Exemplar for Evaluation and Comparison of Self-Adaptation Approaches for Web Applications
by Gabriel A. Moreno, Bradley Schmerl, and David Garlan
Research in self-adaptive systems often uses web applications as target systems, running the actual software on real web servers. This approach has three drawbacks. First, these systems are not easy and/or cheap to deploy. Second, run-time conditions cannot be replicated exactly to compare different adaptation approaches due to uncontrolled factors. Third, running experiments is timeconsuming. To address these issues, we present SWIM, an exemplar that simulates a web application. SWIM can be used as a target system with an external adaptation manager interacting with it through its TCP-based interface. Since the servers are simulated, this use case addresses the first two problems. The full benefit of SWIM is attained when the adaptation manager is built as a simulation module. An experiment using a simulated 60-server cluster, processing 18 hours of traffic with 29 million requests takes only 5 minutes to run on a laptop computer. SWIM has been used for evaluating self-adaptation approaches, and for a comparative study of model-based predictive approaches to self-adaptation.
Download the SWIM artifact at GitHub: