Precise response time analysis for Ravenscar kernels

Abstract

The Ravenscar Profile defines a subset of the Ada95 tasking constructs which can be implemented using a small, reliable kernel. One of the benefits of this approach is to improve the timing analysis because non-deterministic and non-analyzable features are excluded. But to perform a precise schedulability analysis of a Ravenscar compliant application, the kernel overheads must be taken into account. Therefore, a set of metrics and documentation requirements has to be defined in order to model the kernel influence in response time analysis. In this paper the main components of the response time of periodic and sporadic tasks running on a Ravenscar kernel are identified, and the set of kernel metrics which are required to perform a precise timing analysis is identified.