Visualizing a hierarchy of performance models for software systems

Definition of a software process to be analyzed is normally top-down. Analysis starts with a rough description and evolves into finer granularity as more performance and functional requirements become available. This process involves different performance models at each stage. The relationship between these models forms a hierarchy of performance models. Performance parameters propagate bottom-up and the analysis of these models is very complex, so that it is essential to develop computer aided performance evaluation (CAPE) tools to support the evaluation process. In this work we developed a graphical interface for CAPE environments called the Graphical Performance Evaluation (GRAPE) system. GRAPE supports the structural design of five different performance models: queueing, state, computation structure, data flow and statistical models. These models can be used to design parallel/distributed real-time software systems at different levels of granularity. GRAPE is the front-end tool for a CAPE environment that will allow the user to integrate the relationships between different performance metrics at different levels of analysis. These metrics propagate between the modeling hierarchy to arrive at a final quantitative or symbolic measure of its performance.