Challenges for simulation of systems in software performance engineering

In this paper, we describe some challenges simulation and other predictive methods face when applied to software systems. We first describe different types of SW-systems and particularly large IT-Applications (e.g. Banking, Administration, e-Business) that face serious performance requirements and could benefit greatly from simulative evaluation. Widespread application of simulation in this area, however, still has a long way to go. We list several typical challenges simulation and SW-engineering have to overcome to find to a mutually beneficial co-operation. We particularly focus on the role Unified Modelling Language (UML) could play in combining both worlds. This paper is based on our experiences of applying simulation in software engineering and is presented as a collection of theses aimed to encourage discussion.