1.Frame diagram It is known as the best io multiplexing method in the current era; Core operations: a tree (red-black tree), a table (kernel linked list) and three interfaces; Thought: (fd represents file descriptor) epoll will mount the detected event fd to the red-black tree in the kernel space, traverse the red-black tree, call the […]
Tag: multiplexing
io multiplexing epoll
1. What is epoll? epoll is an event notification mechanism provided by the Linux kernel, which is used to manage I/O events of a large number of file descriptors. It is one of the key components of high-performance event-driven programming currently widely used on Linux systems. Compared with traditional select and poll, epoll performs better […]
Linux driver IO article – IO multiplexing
Article directory What is IO multiplexing Three methods of IO multiplexing select poll poll system call process Implementation of poll mechanism in driver What is IO multiplexing Simply put, it is a method to operate multiple devices at the same time and process data from multiple devices in a timely manner. Specifically, it refers to […]
Network Programming 3: Multiplexing + Signal Driver
1. Multiplexing (Key Points) 1. Monitor multiple sockets at the same time Blocking IO—->Only one socket can be monitored at the same time Non-blocking IO —> Keep polling and ask the IO port if there is any data coming, which is a waste of CPU resources. 2. What is multiplexing That is to add the […]
IO multiplexing (select model implements monitoring of two devices: custom device and mouse device)
1. Driver #include <linux/init.h> #include <linux/module.h> #include <linux/cdev.h> #include <linux/fs.h> #include <linux/io.h> #include <linux/slab.h> #include <linux/wait.h> #include <linux/uaccess.h> #include <linux/device.h> #include <linux/poll.h> struct cdev *cdev; char kbuf[128]={0}; unsigned int major=0; unsigned int minor=0; dev_t devno; module_param(major,uint,0664);//It is convenient to pass the major value on the command line struct class*cls; struct device *dev; unsigned int condition=0; […]
Network communication multiplexing and concurrent servers
What is multiplexing: similar to switch in C language. In a nutshell, it is: the ability of a single thread or single process to monitor whether several file descriptors can perform IO operations at the same time. Multiplexing can be used to monitor multiple client operations. principle: Create a collection that holds the file descriptors […]
PY32F003F18 port multiplexing function mapping
PY32F003F18 port multiplexing function mapping, GPIO pins can be configured as input, output, analog or multiplexing functions. 1. Port A multiplexing function mapping In the multiplexed function mapping table of port A, each pin has AF0~AF15. By modifying the values of AF0~AF15, the corresponding multiplexed energy pin can be mapped to the CPU pin. Modify […]
[Network Programming] IO Multiplexing
IO multiplexing is an efficient I/O processing method that allows a single process to monitor multiple file descriptors (sockets, files, etc.) Processed when ready for I/O operations. Its core is to use a small number of threads or processes to manage multiple I/O operations to improve system performance and response speed. 1. Concept 1. The […]
Linux development I/O multiplexing Select model Epoll model
1. Introduction 1. Disadvantages of multi-process servers: 1. Requires a lot of calculations 2. A large amount of memory space The required number of threads is n(n-1)/2, and the computational complexity is O(n^2). 2. Select model: The required number of threads is n, and the computational complexity is O(n). 2. SelectModel specific steps: Steps Set […]
Advanced IO—Select of five IO models & multiplexing
Article directory Five IO models 1. Blocking IO 2. Non-blocking IO 3. Signal driven IO 4. Multiplex IO 5. Asynchronous IO SummaryIO Synchronous and asynchronous Blocking and non-blocking Set up non-blocking Use the fcntl interface to implement a non-blocking function Select for multiplexing select function prototype fd_set structure return value socket ready condition Ready Ready […]