Affiliations: Université Paris-Sud 11, LRI, 91 405 Orsay,
France | INRIA Rocquencourt, Domaine de Voluceau, 78 153 Le
Chesnay, France | ECE, LACSC, 53 rue de Grenelle, 75 007 Paris,
France
Abstract: In this paper, we focus on a non-preemptive scheduling, combining
fixed priorities and dynamic priorities on a uniprocessor. This scheduling is
called FP/DP. Results presented in this paper can be applied indifferently to
tasks and flows. With any flow are associated a fixed priority denoting the
importance degree of the flow and a temporal parameter, used to compute the
dynamic priority. A packet can be transmitted only if there is no packet having
a higher fixed priority and if this packet has the highest dynamic priority
among all packets having its fixed priority. We are interested in the worst
case response time of a sporadic flow set scheduled FP/DP and establish new
results improving the classical FP analysis. Two examples of FP/DP
scheduling are considered: FP/FIFO and FP/EDF. We show that FP/EDF
dominates FP/FIFO when packets sharing the same fixed priority have the same
processing time.
Keywords: Real-time scheduling, fixed priority scheduling, dynamic priority scheduling, worst case response time, deterministic guarantee, quality of service
