Deriving period restrictions from a given utilization bound under RMS

The analysis associated with priority based scheduling usually assumes that task periods are fixed by operational requirements. In this paper we consider systems in which the overriding requirement is to recognise and respond to events originating in the system's environment. An algorithm is presented which can deterministically choose task periods so that event deadlines are satisfied, whilst attempting to maximise the number of such events which can be dealt with. Although it is shown that a simple optimal priority ordering scheme is not possible, an effective heuristic for choosing priorities is presented.