Fitting Linux Device Drivers into an Analyzable Scheduling Framework
Theodore P. Baker
Workshop on Operating Systems Platforms for Embedded Real-Time applications (OSPERT 2007)
Pisa, Italy, July 3, 2007
Summary
Successful application of scheduling theory to embedded real-time systems implemented over an operating system requires matching the actual workloads and scheduling policies of the operating system components, including device drivers, to workload models and scheduling polices that can be analyzed. Progress has been made in API extensions and performance improvements to the Linux operating system that enable it to be used for a range of embedded real-time applications, using priority preemptive scheduling. Powerful techniques for analytical verification of application timing constraints, including Rate Monotonic Analysis and Response Time Analysis exist for systems developed around a fixed-priority preemptive scheduling framework. This paper assesses the degree to which the effects of device drivers in Linux can now be modeled adequately for schedulability analysis, and what remains to be done to reach that goal.