Research And Implementation Of EDZL Real-Time Scheduling Strategy On Multi-core Platforms

Multi-core architectures are introduced to increase processor performance and are increasingly applied in real-time systems. So research on multi-core real-time scheduling has received more and more attention in both academia and industry. Global scheduling strategy, with the advantage of fewer task preemptions and higher resource utilization, has been one of the main research focuses in the field of real-time scheduling. EDZL (Earliest Deadline First until Zero Laxity) is an outstanding global scheduling strategy for its strong real-time performance and high resource utilization properties.Most of the multi-core scheduling algorithms are not implemented in the actual real-time operating systems, and the data on the runtime scheduling overhead and schedulability analysis are also scanty, which limit their practical application in real-time systems. So there is an urgent need to provide an experimental platform for multi-core real-time operating systems that can verify the actual performance of real-time scheduling algorithms. LITMUSRT (Linux Testbed for Multiprocessor Scheduling in Real-Time systems), a popular experimental platform for multi-core real-time scheduling, needs to be further developed and improved due to its limited support on real-time scheduling algorithms.In this paper, the EDZL real-time scheduler, supporting EDZL global scheduling strategy effectively, is designed and implemented based on Linux kernel2.6.34with integrated Litmus2010-2patch. The three key technologies have been studied and developed, which include the runtime states transition and processes preemption of real-time task routines, the capture and handling of zero-laxity events, and the efficient dynamic priority queues management during the entire life cycle of real-time routines. The real-time application management system with a graphic user interface has been developed to simplify the creation and runtime management of real-time routines. The correctness and effectiveness of the EDZL scheduler has been demonstrated by sufficient experiments. This work enables run-time performance analysis and comparison between more multi-core scheduling algorithms, and will promote the application of the EDZL scheduling strategy in practical real-time systems.