实时操作系统中共享Cache划分技术的研究与应用

发布时间：2018-04-26 18:42

本文选题：数控技术 + 实时系统　；参考：《中国科学院研究生院（沈阳计算技术研究所）》2012年硕士论文

【摘要】：数控技术是利用数字信息对机械运动和工艺过程进行高性能的自动控制，极大地提高产品加工质量、加工精度和工作效率。数控技术正朝着性能上高速度、高精度；结构上开放化、网络化；功能上集成化、复合化、智能化的方向快速发展，开放式数控系统已成为发展必然。开放式数控系统不但需要具有更高数据处理能力的多核处理器作为硬件支撑，也需要与之相配套的高性能实时操作系统作为其软件平台。目前，主流多核处理器采用的共享Cache结构带来更加严重的共享Cache冲突现象，系统将被迫频繁替换Cache中的数据以保证不同核心上并发任务的数据需求，任务执行时间更加难以预测，甚至导致数控系统实时任务集不可调度，降低了系统的整体性能。针对共享Cache冲突现象出现了众多相关解决方案。其中，共享Cache划分能够为任务分配独占的Cache空间直到任务执行结束，，从而有效的避免了共享Cache冲突的发生。因此，本文采用基于软件的共享Cache划分方法改造现有的数控系统：首先，建立基于隐马尔科夫链的共享Cache冲突模型，分析多核实时环境下共享Cache冲突问题对系统的影响，并预测任务的共享Cache行为；其后，根据模型输出的性能参数为数控任务建立静态、动态划分函数并计算划分空间的大小；最后，使用“页面着色”技术改造现有数控系统，实验证明共享Cache划分方案显著提高了数控系统实时性。
[Abstract]:Numerical control technology is the use of digital information to control the mechanical movement and process of high performance automatic control, greatly improve the product processing quality, processing accuracy and working efficiency. Numerical control technology is developing rapidly in the direction of high speed and precision in performance, opening up in structure, networking, integration in function, compound and intelligence. Open CNC system has become a necessity. The open CNC system not only needs the multi-core processor with higher data processing ability as the hardware support, but also needs the matching high-performance real-time operating system as its software platform. At present, the use of shared Cache architecture in mainstream multicore processors leads to more serious shared Cache conflicts, and the system will be forced to replace the data in Cache frequently to ensure the data requirements of concurrent tasks in different cores. Task execution time is more difficult to predict, even leading to the real-time task set of NC system can not be scheduled, which reduces the overall performance of the system. There are many related solutions to the conflict of shared Cache. The shared Cache partition can allocate exclusive Cache space to the task until the end of the task execution, which effectively avoids the sharing Cache conflict. Therefore, this paper uses the software-based shared Cache partition method to transform the existing numerical control system. Firstly, the shared Cache conflict model based on Hidden Markov chain is established, and the impact of the shared Cache conflict problem on the system under multi-verification environment is analyzed. The shared Cache behavior of the task is predicted. Then, according to the performance parameters of the model, the static and dynamic partition functions are established for the NC task and the size of the partition space is calculated. Finally, the existing NC system is modified by "page coloring" technology. The experiments show that the shared Cache partitioning scheme improves the real-time performance of CNC system significantly.
【学位授予单位】：中国科学院研究生院（沈阳计算技术研究所）
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP332

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