發(fā)布時間：2019-01-26 20:02

【摘要】：嵌入式系統(tǒng)是計算機(jī)系統(tǒng)的一個重要分支。伴隨著計算機(jī)應(yīng)用場合的越來越廣泛，嵌入式系統(tǒng)的應(yīng)用也變得越來越多。作為以應(yīng)用為目的的學(xué)科，嵌入式系統(tǒng)極大的提高和方便了我們的生活，在我們的生活中它是如影隨形。如PDA，手機(jī)，汽車，甚至是導(dǎo)彈發(fā)射裝置中，嵌入式系統(tǒng)都有廣泛的存在。 嵌入式操作系統(tǒng)是嵌入式系統(tǒng)的核心，它設(shè)計的好壞直接關(guān)系到整個嵌入式系統(tǒng)的穩(wěn)定可靠與否。而自嵌入式系統(tǒng)出現(xiàn)在世界上一問世，，人們對于它的操作系統(tǒng)就表現(xiàn)出了深厚的興趣，對它的研究和開發(fā)就從來沒有停止過。 μC/OS-II系統(tǒng)作為一個嵌入式操作系統(tǒng)，源代碼表現(xiàn)出精妙的設(shè)計和精練濃縮的結(jié)構(gòu)，同時可讀性也非常強(qiáng)，這些都為業(yè)界所稱道。它實(shí)現(xiàn)了一個操作系統(tǒng)所基本上能夠達(dá)到的功能，但它最主要的是微內(nèi)核的設(shè)計使它的應(yīng)用范圍變得越來越廣[1]。 本文首先對μC/OS-II操作系統(tǒng)進(jìn)行內(nèi)核分析，全面的掌握系統(tǒng)的調(diào)度機(jī)制，然后提出系統(tǒng)存在的不足。如系統(tǒng)只支持一個優(yōu)先級只對應(yīng)一個任務(wù)的調(diào)度，可支持的任務(wù)數(shù)量不多，同時也存在著低優(yōu)先級的任務(wù)等待時間過長等情況。針對以上問題，結(jié)合系統(tǒng)自身的優(yōu)勢，本文設(shè)計出改進(jìn)的系統(tǒng)內(nèi)核新的調(diào)度算法，新的調(diào)度算法是以優(yōu)先級調(diào)度為第一層調(diào)度。新的調(diào)度算法重新定義了所需要的數(shù)據(jù)結(jié)構(gòu)，如任務(wù)控制塊。接著對新設(shè)計算法的結(jié)構(gòu)組織圖，控制塊的初始化，鏈表的建立，調(diào)度的過程，任務(wù)的刪除等方面進(jìn)行說明。最后，改進(jìn)了相關(guān)的函數(shù)，給出了新函數(shù)的執(zhí)行過程。根據(jù)系統(tǒng)任務(wù)要求的不同，將它們分成兩類：實(shí)時任務(wù)和分時任務(wù)。 實(shí)時任務(wù)占用優(yōu)先級的前16個，每一個實(shí)時任務(wù)都完全占有一個優(yōu)先級，而且系統(tǒng)仍然是第一時間響應(yīng)它的調(diào)度，滿足某些任務(wù)要求實(shí)時調(diào)度情況。分時任務(wù)占用的優(yōu)先級界于實(shí)時任務(wù)與統(tǒng)計任務(wù)，空閑任務(wù)之間的這個區(qū)段。分時任務(wù)主要是用于那些要求核心處理器響應(yīng)不是那么迅速的任務(wù)，可以多個任務(wù)共同占用一個優(yōu)先級。它們通過雙向鏈表來進(jìn)行存儲。分時任務(wù)以優(yōu)先級調(diào)度作為第一層調(diào)度，以時間片調(diào)度作為第二層調(diào)度。當(dāng)具有同一優(yōu)先級的多個分時任務(wù)獲得處理器調(diào)度的機(jī)會時，系統(tǒng)會對這個鏈接在OSTCBPrioTbl[]上的任務(wù)控制塊鏈表進(jìn)行分時調(diào)度算法。在分時任務(wù)的執(zhí)行調(diào)度過程中，每執(zhí)行完一個分時任務(wù)，它都要查看是否有高優(yōu)先級的實(shí)時任務(wù)就緒，有則系統(tǒng)響應(yīng)實(shí)時任務(wù)，無則對任務(wù)控制塊鏈表邊遍歷邊執(zhí)行。而在這個過程中，高優(yōu)先級的分時任務(wù)是沒有打斷正在執(zhí)行的分時任務(wù)的權(quán)限的。 通過調(diào)度算法的改進(jìn)，合理安排任務(wù)的優(yōu)先級。做到實(shí)時任務(wù)滿足快速調(diào)用，分時任務(wù)合理設(shè)置優(yōu)先級和時間。這樣，既能夠滿足μC/OS-II系統(tǒng)的實(shí)時性要求，又能夠?qū)崿F(xiàn)同一優(yōu)先級下可以擁有多個任務(wù)，同時，擴(kuò)大操作系統(tǒng)可以支撐的任務(wù)的數(shù)量。 最后，通過對新的內(nèi)核調(diào)度算法進(jìn)行實(shí)驗(yàn)測試，可以發(fā)現(xiàn)新的內(nèi)核調(diào)度算法能夠滿足上面所提到的要求。
[Abstract]:The embedded system is an important branch of the computer system. With the application of computer, the application of embedded system has become more and more. As an application-oriented subject, the embedded system greatly improves and facilitates our lives, and in our lives it is like a shadow. such as a PDA, a mobile phone, an automobile, or even a missile launching device, and the embedded system has a wide range of existence. The embedded operating system is the core of the embedded system, and its design is directly related to the stability and reliability of the whole embedded system. No. And since the embedded system appeared in the world, people expressed deep interest in its operating system and never stopped its research and development..... mu.C/ OS-II system as an embedded operating system, the source code shows a fine design and a refined and concentrated structure, and the readability is also very strong, all of which are the industry It realizes the function that an operating system can basically achieve, but the main thing is that the design of the micro-kernel makes its application range more and more wide[1]. In this paper, the kernel analysis of the operating system of the. mu.C/ OS-II is first carried out, the scheduling mechanism of the system is fully grasped, and then the system is put forward. the system only supports the scheduling of only one task, the number of tasks that can be supported is not large, and the task waiting time of the low priority exists In view of the above problems, in combination with the advantages of the system itself, this paper designs a new scheduling algorithm for the system kernel, and the new scheduling algorithm is based on the priority. the new scheduling algorithm redefines the required data structure, e.g., the task control block is followed by the structure organization chart of the new design algorithm, the initialization of the control block, the establishment of the linked list, the process of scheduling, the deletion of the task, and the like. The surface is described. Finally, the correlation function is improved and a new function is given. The execution process of the system. Depending on the system's task requirements, they are divided into two categories: real-time tasks and the system is still the first time to respond to the scheduling to meet certain tasks. real-time scheduling. The priority level occupied by the task is in real-time tasks and statistics tasks, idle tasks This section between tasks is mainly used for tasks that require that the core processor response is not so fast that multiple tasks can be shared takes up a priority. They go through two-way the task of the time division is scheduled as the first layer according to the priority schedule, and the time slice is scheduled; As the second layer scheduling, when a plurality of sub-tasks with the same priority are provided with the opportunity to schedule the processor, the system proceeds to the task control block linked list on the OSTCBPrioTbl[] in that execution and dispatch of the time-division task, every time a sub-task is run, it is to check whether there is a high-priority real-time task ready, and if the system responds to the real-time task, the task control block chain is not the table edge traverses the edge to perform. In this process, the high-priority sub-task is not to interrupt the point being executed by the improvement of the scheduling algorithm. The priority of the task is to be arranged. The real-time task can meet the quick call and the time-division task. the invention can not only meet the real-time requirements of the. mu.C/ OS-II system, but also can have a plurality of tasks under the same priority, and meanwhile, the expanded operating system can In the end, the new kernel scheduling algorithm can be discovered by carrying out the experiment test on the new kernel scheduling algorithm.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：TP316.84;TP368.1

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本文編號：2415859