Chapter 12 USING THE SHE METHOD FOR UML-BASED PERFORMANCE MODELING B.D. Theelen, P.H.A. van der Putten and J.P.M. Voeten Information and Communication Systems Group, Faculty of Electrical Engineering, Eindhoven University of Technology. P.O. Box 513, 5600 MB Eindhoven, The Netherlands. E-mail: B.D.Theelen@tue.nl Abstract: The design of complex real-time distributed hardware/software systems com- monly involves evaluating the performance of several design alternatives. Early in the design process, it is therefore desirable that design methods sup- port constructing abstract models for the purpose of analysis. Recent exten- sions to the Unified Modeling Language (UML) that enable specifying sched- ulability, performance and time provide a means to start developing such mod- els directly after defining the concepts and requirements of a system. How- ever, UML hampers the evaluation of performance properties because this re- quires constructing executable models with a modeling language that supports application of mathematical analysis techniques. In this paper, we present how the Software/Hardware Engineering (SHE) method can be used for the per- formance modeling of real-time distributed hardware/software systems. Start- ing from a UML specification, SHE enables constructing formal executable models based on the expressive modeling language POOSL (Parallel Object- Oriented Specification Language). Keywords: Formal Semantics, Performance Modeling, Parallel Object-Oriented Specifica- tion Language (POOSL), System-Level Design, and Unified Modeling Lan- guage (UML). 1. INTRODUCTION Designing complex real-time distributed hardware/software systems en- tails considering different options for realizing the demanded functionality. In the early phases of the design process, deciding for a certain design alter- native may have a deep impact on the final performance of the system. To evaluate the performance of design alternatives before actually implement-