Research On Real-time Scheduling Of Embedded Operating System For Multi-core SPARC Architecture

As the tasks of aerospace work become more and more complex,the technical requirements are gradually increasing.In order to improve the real-time performance and stability of spacecraft and reduce the impact of software system delay on spacecraft,real-time operating systems have been widely studied and applied.As a general processor architecture for aerospace equipment in the world,SPARC architecture can process program instructions in a simplified and efficient manner,avoiding the problem of low execution efficiency caused by redundancy of embedded system instructions.Among them,the multi-core SPARC architecture has received extensive attention due to its easy expansion,high performance,and low power consumption.Therefore,it is of great significance to study the real-time scheduling method under multi-core SPARC.In this paper,the real-time task scheduling of multi-core operating system is studied deeply,and the main parameters and constraints of real-time tasks are introduced.The schedulability of several real-time scheduling algorithms under the multi-core operating system is analyzed by comparing the calculation and comparison of the utilization boundary of the scheduling algorithm,and the load balancing process is designed.At the same time,according to the time constraints required by hard real-time systems,the effects of synchronization mechanism and interrupt handling mechanism of multi-core operating systems on real-time scheduling are analyzed.Then it transplants Free RTOS,a real-time kernel with simple structure and focus on task management and scheduling.Based on the characteristics of multi-core SPARC processor,the kernel configuration of the embedded real-time operating system is modified,a compilation environment is built,and the kernel initialization design is completed.The modification scheme of the hardware description layer is formulated,including tick timer setting,scheduler startup and context switching,etc.The mutual exclusion of multi-core shared resources and the protection of critical sections are realized through the mutual exclusion lock structure.The priority inheritance protocol is used to ensure the normal operation of key tasks without being blocked,ensuring real-time performance.The processor affinity mechanism is used to achieve load balancing under multi-core,and support tasks to bind processors or run randomly.Finally,the function and performance of the transplanted Free RTOS are tested on the simulator and FPGA equipped with multi-core SPARC processors.Completed the multi-core startup and scheduling of the operating system for multi-core SPARC processors.The multi-task scheduling,real-time preemption,signal synchronization and priority inversion functions are tested,and the test results are correct.The scheduling delay is tested,and the average delay is 75μs when the system frequency is 50 MHz,which meets the requirements of the real-time operating system.