Wiley Systems Engineering with SDL: Developing Performance-Critical Communication Systems (Wiley Series on Communications Technology)

Excerpt. © Reprinted by permission. All rights reserved. Excerpt from Systems Engineering with SDL by Mitschele-Theil From The Foreward Performance engineering means to describe, to analyze and to optimize the dynamic, time- dependent behavior of systems. However, it is common for a system to be fully designed and functionally tested before an attempt is made to determine its performance characteristics. The redesign of software and hardware is costly and may cause late system delivery. There are many dramatic examples of this from both the communication and computer industries, most recently concerning Internet providers. Responsible managers state that performance is the major cause of project failure. Moreover, there are many situations in which the functional properties of a system are directly influenced by the temporal behavior and vice versa. For example, communication protocols usually need time-out mechanisms; whether they deadlock or not is dependent on the selected timing parameter. A second example: analysing the performance of multiprocessors and distributed systems, functional dependencies and communication between distributed sub- tasks have to be carefully considered; program execution, efficient resource utilization and speed up may crucially depend on them. Therefore, it is clear that performance engineering has to be integrated into the design process from the very beginning. The provision of tool-supported methods that can be integrated into commonly accepted and widely used software engineering techniques has a key position in this domain. In the area of development of telecommunications systems, the specification and description techniques SDL and MSC have played a dominate role for years. Both languages are standardized by the ITU. Despite the availability of tools for the generation of code from SDL specifications which target a variety of platforms, systematic investigations of the optimization of the generated code have not yet been performed and published. The book presents an investigation of the SDL-92/96 version of the SDL language. It addresses an improvement of the run-time properties by taking into account the characteristics of the applications (communication protocols) and different process scheduling and management strategies. The author concentrates on the efficient implementation of behavioural concepts. For the treatment of issues arising from object-oriented concepts the author applies the traditional flattening approach of the language standard. It is expected that a direct solution would result in further improvements for the performance of SDL-based applications. The special value of this book lies in the systematic presentation of different implementation strategies, their constraints and their impact on performance. From these results we can derive concrete rules for the design and implementation of application- and platform-specific SDL compilers. Most of the results can also be applied to the most recent language version, i.e. SDL-2000. It is a very demanding task to describe both worlds, that is, formal specification techniques on one side and performance evaluation and optimization on the other, to survey their essential points and to summarise a state-of-the-art integrated design process. However, the author presents for the first time a systematic and didactically convincing treatise, which explores the question of how to embed methods of performance engineering in real software development technologies. We believe that this publication will become a standard reference for performance engineers, promoting critical discussions and further research activities in this area. Prof. Dr Joachim Fischer Humboldt-Universitdt zu Berlin rlangen-Niirnberg Prof. Dr Ulrich Herzog, Friedrich-Alexander-Universitdt Erlangen-N|rnberg Product Description SDL (Specification and Description Language) is a modern, high-level programming language intended for the description of comple