One benefit of SOA is from service composition which combines existing services to form a new valued-added service in the form of business process.This also creates the need to ensure that the performance of those composite services meets the business requirements.This paper proposes a method for evaluating the performance of composite services.We automatically transform a composite service modeled by BPEL,into a performance model based on Layered Queuing Networks(LQN)and then leverage existing LQN solvers to predict their performance.The inputs to our transformation algorithm are an XML file which contains a service composition model complying with the BPEL4WS specification,a related performance profile and a service topology.The output of the model is the corresponding LQN model which can be directly analyzed using existing LQN solvers.
