Study Of Real-time Performance For Dynamic Memory Management And Context Switching Of The BWDSP104X

As the development of personal consumer electronics, industrial control, commu-nications, and national defense, embedded real-time systems had higher requirements for flexibility and complexity. The embedded real-time operating systems, with its mul-titasking management capabilities, customizable and scalable, low-power consumption, high real-time, etc. were widely used in embedded systems.To support multi-task management functions in embedded systems, the operating system needed to provide the ability to multi-task management. Tasking-switching must have a context switching operation. In order to reduce the overhead of task switching, real-time operating system should have a fast context switching mechanism.In addition, in order to meet the requirements of flexibility and functionality to the embedded application, embedded operating systems needed to provide a flexible memory management mechanism-dynamic memory management, and dynamic mem-ory management should overcome the shortcomings in terms of real time.In this paper, in order to study these two problems, combined with the radar infor-mation collection system-BWDSP104X digital signal processor system, the dynamic memory management mechanism and context switching mechanism of operating sys-tem for real-time research and analysis carried out. The main work included the follow-ing two aspects:1. We provided a TLSF(Two-level Segregated Fit) dynamic memory allocator for RTEMS to meet the real-time requirement of the project. At first, we got the time com-plexity of TLSF algorithm via static analysis of the memory allocation and dealloca-tion code. After that, we performed experiments to compare the new dynamic memory manager based on TLSF algorithm with RTEMS operating system originally dynamic memory allocator on the time performance of allocation and deallocation operations, and fragmentation rates. Experimental results show that, TLSF memory allocator has better time performance and lower fragmentation rates.2. As the project has a lot of context registers in the DSP system, up to1303, after completing RTEMS operating system migration on the BWDSP104X, we should reduce the time consuming of context switching. The BWDSP104X had features for having a dual data paths, providing multiple storage blocks can be accessed in parallel, general-purpose register banks can be accessed in parallel. To reduce the overhead of context switching, we proposed a solution based on the features of the BWDSP104X. We split registers of context into two parts, and saved them in two memory parts which can be subjected to parallel access. When context switching, saving and restoring the registers of context via dual data paths rather than one. This solution had been implemented in the RTEMS operating system. The experimental results show that saving and restoring the registers via dual data paths can reduce the processing time by49.04%comparing to one data path.