Schedulability Analysis of Global Scheduling Algorithms on Multiprocessor Platforms

Research on real-time scheduling algorithms for multiprocessor systems is a hot topic, due to the recent popularity of multicore hardware platforms. When executing applications with dynamic requirements on symmetric multiprocessor platforms, a possibility is to use global scheduling, where ready tasks are inserted in a single system-wide queue and migration from one processor to another is allowed during task lifetime. This paper addresses the problem of schedulability analysis of globally scheduled periodic and sporadic task sets. First, a general method to derive schedulability conditions for multiprocessor real-time systems will be presented. The analysis will be applied to two typical scheduling algorithms: Earliest Deadline First (EDF) and Fixed Priority (FP). Then, the derived schedulability conditions will be tightened, refining the analysis with a simple and effective technique that significantly improves the percentage of accepted task sets. The effectiveness of the proposed test is shown through an extensive set of synthetic experiments.