An application-based EDF scheduler for OSEK/VDX

Earliest deadline first scheduling performs processor utilization up to 100 percent and improved robustness in overload situations. However, most automotive applications are running under static priority policy. Because of this, the standard operating system in the automotive industry, OSEK/VDX, just supports priority scheduling. This paper describes an EDF scheduler plug-in for OSEK/VDX. The plug-in provides EDF scheduling without changes to the operating system by delaying task activations. The add-on was tested for an engine management system developed by SiemensVDO. Results of this experiment are presented and discussed, showing that the EDF scheduling techniques can improve the system in aspects of robustness and resource utilization.