Performance Modeling of Distributed Collaboration Services with Independent Inputs/Outputs

This paper deals with modeling and performance analysis of dis-tributed applications, service compositions and workflow systems. From the functional perspective, the distributed application is modeled as an activity in-volving several roles, where behavior is defined in terms of compositions from several sub-activities using the standard sequencing operators found in UML Activity Diagrams. Each activity is characterized by a certain number of input and output events, and the performance of the activity is defined by the mini-mum delays that apply for a given output event in respect to each input event. We use a partial order to model these events, whose delays can be measured through testing. We also provide general formulas to calculate the performance of a composite activity from the performance of its constituent sub-activities and the control structure specifying the order of execution. Proofs of correct-ness for these formulas, along with a simple example are also given.