Optimal Design And Research On Multi-core Scheduling Mechanism Of ACoral Embedded Operating System

With the widespread application of multi-core processors in embedded devices,embedded multi-core operating systems are also commonly used in aviation,aerospace,weaponry,and consumer industries.However,most of the existing embedded multi-core operating systems have relatively simple support for multi-core scheduling mechanisms.In addition,in safety-critical fields such as aerospace and aviation,operating systems often require mixed scheduling of safety-critical time-deterministic tasks and real-time tasks triggered by accidental events.Considering the constraints of shared resources,there is still a lack of admission control methods that support the dynamic joining of sporadic real-time tasks.Based on the above background,this thesis aims at the shortcomings of the existing embedded multi-core operating system,researches and designs a multi-core scheduling mechanism that supports multi-core task scheduling,shared resource management,system load balancing,task schedulability analysis,and is based on aCoral embedded multi-core operation The system implements the multi-core scheduling mechanism.The main research contents and contributions of this thesis are as follows:(1)For the problem of dynamic joining of sporadic real-time tasks,a multi-core scheduling mechanism based on multi-level scheduling is constructed based on the aCoral embedded real-time operating system.The first level is admission control,which judges whether new tasks can be added to the current system through online schedulability analysis;the second level is task assignment and resource allocation,which allocates specific processor cores and sets priorities for tasks and resources.The third level is the runtime scheduling mechanism,including the multi-core real-time scheduling mechanism and the multi-core real-time lock protocol.(2)Based on the aCoral operating system,table scheduling algorithm and P-FP scheduling algorithm are implemented.Time-deterministic tasks use table scheduling algorithm for task scheduling,and sporadic real-time tasks use P-FP scheduling algorithm for task scheduling.Aiming at real-time access control of shared resources in the embedded multi-core real-time operating system,based on the core rules of the DPCP protocol,a distributed multi-core semaphore lock protocol based on task migration is proposed.The lock protocol solves the difficulties of DPCP implementation in an embedded environment with limited resources,increases the priority of the local core ceiling,changes a waiting queue for each resource to a global resource waiting queue,and reduces the time overhead of the lock protocol for judging the task's ability to obtain resources.(3)For the scenario where there are shared resource constraints in the multi-core situation and there are table scheduling tasks and P-FP scheduling tasks at the same time,system modeling is used to analyze the worst response time of dynamically added sporadic real-time tasks,and then the response time-based The schedulability analysis method performs schedulability analysis of this type of task.(4)Considering load balancing and ensuring system schedulability,we have studied and implemented an admission control mechanism that can perform task priority assignment,task core division,resource division,and schedulability analysis,and proposes admission control in the operating system Implementation plan.