7. Early Time-Budgeting for Component-Based Embedded Control Systems

One of the challenging steps in the development of component based embedded control systems involves decomposition of feature or system level timing requirements into component level timing requirements. Often it is observed that the timing is introduced at a later stage in the development cycle and ad hoc estimates are made which lead to costly and multiple design iterations. This chapter proposes a methodology that addresses this problem using a simple but powerful idea of using parametric specification. A key step in the methodology is component time-budgeting, which involves identifying a set of parametric timing requirements for the components realizing a feature functionality. This is followed by a verification step which computes a set of constraints on the parameters such that any valuation of the parameters satisfying the constraints achieves the feature requirements. This avoids the ad hoc time estimates and the consequent design iteration. The methodology is formalized using Parametric Temporal Logic and illustrated on a reasonably sized automotive case study.