Priority Inversion at the Network Adapter when Scheduling Messages with Earliest Deadline Techniques

In this paper we present a novel approach in the study of the predictability of real-time message transmission and its relationship with the design of network adapters for real-time distributed systems. The aim is to limit the occurrence of large priority inversions among messages, so as to achieve a better degree of predictability. We show that when the proper network adapters are used in conjunction with earliest deadline message scheduling the loss in processor utilization is minimized and predictable. 1 Introduction The growing interest of industries in robust and cost effective control systems, is pushing the real-time research community into deeper investigations in the distributed area. As a consequence, the literature on distributed real-time computing is expanding rapidly, according to the on-going research. One of the main goal in designing a real-time system is predictability. The scheduling of real-time messages in communication networks, too, is aimed at this goal. So far..