Improving the Quality of Control of Periodic Tasks Scheduled by FP with an Asynchronous Approach
Patrick Meumeu Yomsi, Laurent George, Yves Sorel, Daniel de Rauglaudre · 2009
The aim of this paper is to address the problem of correctly dimensioning real-time embedded systems scheduled with Fixed Priority (FP) scheduling. It is well known that computers which control systems are greatly affected by delays and jitter occurring in the control loop. In the literature, a deadline reduction approach has been considered as one solution to reducing the jitter affectinga task, thereby obtaining better loop stability in the contro l loop. Here, in order to improve the sensitivity of the deadlines, we propose another solution for reducing the worst case response time of the tasks, hence reducing the jitter, when all the tasks are scheduled with the Deadline Monotonic Algorithm. This is performed for a specific asynchronous scenario for harmonic periodic tasks. We compare the results to those for the synchronous scenario in terms of minimum deadline reduction factor preserving the schedulability of tasks set in both cases.