On the Design of an Optimal Multiprocessor Real-Time Scheduling Algorithm under Practical Considerations (Extended Version)

TL;DR

This paper presents an improved optimal multiprocessor real-time scheduling algorithm based on BF, with proven optimality, lower complexity, and a schedulability analysis considering OS overheads.

Contribution

It introduces a new adaptation of the BF algorithm that is optimal, valid, and computationally efficient, along with a novel schedulability test for multiprocessor systems.

Findings

The improved BF algorithm is optimal and always feasible when a schedule exists.

The new algorithm has a computing complexity of O(n).

The schedulability analysis accounts for OS overheads, enhancing practical applicability.

Abstract

This research addresses the multiprocessor scheduling problem of hard real-time systems, and it especially focuses on optimal and global schedulers when practical constraints are taken into account. First, we propose an improvement of the optimal algorithm BF. We formally prove that our adaptation is (i) optimal, i.e., it always generates a feasible schedule as long as such a schedule exists, and (ii) valid, i.e., it complies with the all the requirements. We also show that it outperforms BF by providing a computing complexity of O(n), where n is the number of tasks to be scheduled. Next, we propose a schedulability analysis which indicates a priori whether the real-time application can be scheduled by our improvement of BF without missing any deadline. This analysis is, to the best of our knowledge, the first such test for multiprocessors that takes into account all the main overheads generated by the Operating System.