Search - implement semaphore

Search - implement semaphore - List

[Software Engineering] 1 DL : 0: In a preemptive priority based RTOS, priority inversion problem is among the major sources of deadline violations. Priority inheritance protocol is one of the approaches to reduce priority inversion. Unfortunately, RTOS like uC/OS can’t support priority inheritance protocol since it does not allow kernel to have multiple tasks at the same priority. Although it has different ways to avoid priority inversion such as priority ceiling protocol, developers still have some difficulties in programming real time applications with it. In this paper, we redesign the uC/OS kernel to provide the ability to support round robin scheduling and implement priority inheritance semaphore on the modified kernel. As result, we port new kernel with priority inheritance semaphore to evaluation board, and evaluate the execution time of each of the kernel service as well as verify the operations of our implementation.-In a preemptive priority based RTOS, priority inversionproblem is among the major sources of deadlineviolations. Priority inheritance protocol is one of theapproaches to reduce priority inversion. Unfortunately, RTOS like uC/OS can t support priority inheritanceprotocol since it does not allow kernel to have multipletasks at the same priority. Although it has different waysto avoid priority inversion such as priority ceilingprotocol, developers still have some difficulties inprogramming real time applications with it. In this paper, we redesign the uC/OS kernel to provide the ability tosupport round robin scheduling and implement priorityinheritance semaphore on the modified kernel. As result, we port new kernel with priority inheritance semaphore toevaluation board, and evaluate the execution time of eachof the kernel service as well as verify the operations ofour implementation.
Date : 2025-12-14 Size : 132kb User : 刘天宏
[Software Engineering] readerwriter DL : 0: 实验一用信号量来实现读者-写者问题 (一) 实验目的理解进程(或线程)及信号量的概念 (二) 实验内容 1、定义一个数据缓存buffer及用于实现同步互斥的信号量。 2、定义一个读者函数：当有写者在占用buffer时，读者应该等待，直到写者不再使用该buffer。当有其他读者在占用buffer时，读者可对buffer进行读取操作。当buffer中有数据时，则从其中读取一个数据，并显示然后退出。当buffer中没有数据时，应等待，直到buffer中有数据可读。 3、定义一个写者函数当有读者在占用buffer时，写者应该等待，直到所有的读者都退出为止。当有其他写者占用buffer时，该写者应该等待，直到占用buffer的写者退出为止。当buffer有空闲时，写者应该在buffer中写入一个数据并退出。当buffer满时，写者应该等待，直到buffer有空闲为止。 4、定义主函数，在其中可以任意创建读者与写者。可根据用户输入创建读者或写者进程(线程)。 5、用户界面 (三) 实验要求在实验过程中，显示详细的各进程(线程)的状态及buffer使用情况。 (四) 实验学时 3-Experiments using semaphore to implement a reader- writer problem (A) purpose of the experiment Understand the process (or thread), and the concept of semaphore (b) of the experiment content 1, define a data cache buffer, and synchronization for mutual exclusion semaphore. 2, the definition of a reader function: When a write buffer in the occupation, the reader should wait until the writer is no longer used in the buffer. When there are other readers in the occupied buffer, the reader can read buffer operations. When the buffer has data, from which a data read and displayed and then exit. When the buffer contains no data, they should wait until the buffer has data to read. 3, define the function of a writer When a reader occupied buffer, the writer should wait until all of the readers exit. When the buffer occupied by other writers, the writer should wait until the write buffer occupied by exit. When the buffer in their free time to write should be written in a
Date : 2025-12-14 Size : 120kb User : 镡皓琳