Because that means context switching(save context, restore context)…
Brocade SAN交换机常用命令 使用电脑连接Brocade SAN交换机常用命令 使用电脑连接管理网口,默认IP地址为:10.77.77.77,掩码:255.255.255.0 默认用户名:admin,默认密码password 1. switchStatusShow 查看交换机的总体健康状态 switch:admin> switchstatusshow Switch Health Report Switch Name: SWFCR IP address: 10.33.54.176 Swit…
How many Context Switches is “normal”? This depends very much on the type of application you run. If you've got applications which are very trigger-happy WRT syscalls you can expect to see high amounts of context switching. If most of your applicatio…
1 Introduction This part of the reference manual covers the higher-dimensional kernel. The kernel contains objects of constant size, such as point, vector, direction, line, ray, segment, circle. With each type comes a set of functions which can be ap…
1 Introduction CGAL, the Computational Geometry Algorithms Library, is written in C++ and consists of three major parts. The first part is the kernel, which consists of constant-size non-modifiable geometric primitive objects and operations on these…
## Linux kernel memory-faq.txt What is some existing documentation on Linux memory management? Ulrich Drepper (the ex-glibc maintainer) wrote an article series called "What every programmer should know about memory": Part 1: http://lwn.net/Artic…
How long does it take to make a context switch?   FROM: http://blog.tsunanet.net/2010/11/how-long-does-it-take-to-make-context.html That's a interesting question I'm willing to spend some of my time on. Someone at StumbleUpon emitted the hypothesis t…
FROM: http://blog.tsunanet.net/2010/11/how-long-does-it-take-to-make-context.html That's a interesting question I'm willing to spend some of my time on. Someone at StumbleUpon emitted the hypothesis that with all the improvements in the Nehalem archi…
信号量有一个很明显的缺点,没有区分临界区的读写属性,读写锁允许多个线程进程并发的访问临界区,但是写访问只限于一个线程,在多处理器系统中允许多个读者访问共享资源,但是写者有排他性,读写锁的特性如下:允许多个读者同时访问临界区,但是同一时间不能进入:同一时刻只允许一个写者进入临界区:读者和写者不能同时进入临界区.读写锁也有关闭中断和下半部的版本. RCU:read-copy-update   .................... 问题:rcu相比读写锁,解决了什么问题? rcu的基本原理? 1.…
https://blog.codinghorror.com/understanding-user-and-kernel-mode/ Continue Discussion92 repliesJan '08 JamieF This article should be marked with a caveat that states that most of what it says applies only to .NET programs running on Windows on x86 ha…
In this article I want to share to you on how to create and configure vlan on Linux through Cisco Catalyst Switch. Requirements: 1. Linux installed on a PC with one or more NICs (Network Interface Card). I use Centos 5.4 using 2.6.18-164.11.1.el5PAE…
/* ptrace.c *//* By Ross Biro 1/23/92 *//* edited by Linus Torvalds */ #include <linux/head.h>#include <linux/kernel.h>#include <linux/sched.h>#include <linux/mm.h>#include <linux/errno.h>#include <linux/ptrace.h>#inclu…
/* *  linux/kernel/printk.c * *  Copyright (C) 1991, 1992  Linus Torvalds * * Modified to make sys_syslog() more flexible: added commands to * return the last 4k of kernel messages, regardless of whether * they've been read or not.  Added option to s…
/* *  linux/kernel/vsprintf.c * *  Copyright (C) 1991, 1992  Linus Torvalds */ /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. *//* * Wirzenius wrote this portably, Torvalds fucked it up :-) */ #include <stdarg.h>#include <linux/types.h>…
In recent years, Kernel methods have received major attention, particularly due to the increased popularity of the Support Vector Machines. Kernel functions can be used in many applications as they provide a simple bridge from linearity to non-linear…
这段时候我总是觉得有个问题,u-boot 的存在是不是就是为了调用kernel 而存在的. 所以,粗浅的跟了一下这个流程,还有很多细节上的东西没有做好,往指正. u-boot-2011.9 调用内核代码跟踪1. _start  board_init_r  main_loop.这个流程是u-boot 的一个整体的流程. 2. main_loop()这个函数主要执行一些u-boot 最后的一些工作, #if defined(CONFIG_BOOTDELAY) && (CONFIG_BOOT…
Linux 内核为了处理各种不同类型的的输入设备 , 比如说鼠标 , 键盘 , 操纵杆 , 触摸屏 , 设计并实现了一个对上层应用统一的试图的抽象层 , 即是Linux 输入子系统 . 输入子系统的层次结构体如下 从底层到上层 , input 子系统由 设备驱动层 , 核心层 , 以及事件处理层3个部分组成 当一个鼠标移动, 一个按键按下或弹起 , 它都需要从底层设备驱动-->核心层-->事件处理层 -->用户空间 , 层层上报 , 一直到运用程序. 应用这个input  子系统有如下优…
linux 平台总线的实现有三大块  , platform bus , platform device , platform drvice 平台类型结构体: /** * struct bus_type - The bus type of the device * * @name: The name of the bus. * @bus_attrs: Default attributes of the bus. * @dev_attrs: Default attributes of the dev…
转自 http://www.zhizhihu.com/html/y2010/2292.html Kernel Functions Below is a list of some kernel functions available from the existing literature. As was the case with previous articles, every LaTeX notation for the formulas below are readily availabl…
目录 . sys_call_table:系统调用表 . 内核符号导出表:Kernel-Symbol-Table . Linux 32bit.64bit环境下系统调用入口的异同 . Linux 32bit.64bit环境下sys_call_table replace hook 1. sys_call_table:系统调用表 0x1: sys_call_table简介 sys_call_table在Linux内核中是在Linux内核中的一段连续内存的数组,数组中的每个元素保存着对应的系统调用处理函数…
目录 . 引言 . TCP握手流程 . TCP connect() API原理 . TCP listen() API原理 . UDP交互过程 . UDP send() API原理 . UDP bind() API原理 0. 引言 Monitoring project . outer link connect: connect()->inet_stream_connect . Suspicious port monitor: listen()->inet_listen . SuspiciousU…
现在的kernel里,有个叫做ramfs的文件系统,会把initrd(或者ramdisk,为惯性叫法)里的东西挂载到early-rootfs里(即rootfs,是ramfs的一个特殊实例),执行一些在kenrel里很难执行的操作,这样简化了kernel,方便了调试.随后可以根据需要用switch root过程删掉现在的rootfs,把真正的根文件系统挂载起来. 早期kernel里的这个机制叫做ram disk,但这个机制比较慢,弊端比较多,所以kernel里被ramfs给替代了,但实体文件还叫i…
Uboot_Kernerl_Add_Watch_Dog: U-Boot 2010.06 (Nov 01 2013 - 15:28:44) DRAM:  128 MiBCheck spi flash controller v350... FoundSpi(cs1) ID: 0xEF 0x40 0x18 0x00 0x00 0x00Spi(cs1): Block:64KB Chip:16MB Name:"W25Q128B"*** Warning - bad CRC, using defau…
版本:v1.2   Crifan Li 摘要 本文主要介绍了如何在嵌入式Linux系统运行的时候,进行升级整个Linux系统,包括uboot,kernel和rootfs.以及简介Linux中的已有的通用的Nor Flash驱动m25p80,和简介mtd util以及相关工具mtdinfo,flash_erase,flash_eraseall,nanddump,nandwrite等的基本用法. 本文提供多种格式供: 在线阅读 HTML HTMLs PDF CHM TXT RTF WEBHELP 下…
http://duartes.org/gustavo/blog/post/how-the-kernel-manages-your-memory/ After examining the virtual address layout of a process, we turn to the kernel and its mechanisms for managing user memory. Here is gonzo again: Linux processes are implemented…
虽然这里的Arm Linux kernel前面加上了Android,但实际上还是和普遍Arm linux kernel启动的过程一样的,这里只是结合一下Android的Makefile,讲一下bootimage生成的一个过程.这篇文档主要描述bootimage的构造,以及kernel真正执行前的解压过程. 在了解这些之前我们首先需要了解几个名词,这些名词定义在/Documentation/arm/Porting里面,这里首先提到其中的几个,其余几个会在后面kernel的执行过程中讲述: 1)ZT…
https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=101188&p=807579&hilit=cross+compile+pi+source+code#p807579 http://blog.retep.org/2012/07/08/compiling-a-kernel-on-the-raspberry-pi/ http://blog.csdn.net/jinzheng_2010/article/details/8676…
−Table of Contents Journey to the Center of the Linux Kernel: Traffic Control, Shaping and QoS 1 Introduction 2 Motivation 3 The basics of Traffic Control 3.1 First contact 3.2 Netfilter MARK 3.3 Two classes in a tree 3.4 Connecting the marks to the…
http://loda.hala01.com/2011/12/linux-kernel-%E6%8E%92%E7%A8%8B%E6%A9%9F%E5%88%B6%E4%BB%8B%E7%B4%B9/ Linux Kernel 排程機制介紹 Linux Kernel 排程機制介紹 hlchou@mail2000.com.tw by loda. 2011/12/2 多核心架構儼然是目前智慧型手機方案的新趨勢,隨著省電與效能上的考量,多核心的架構各家方案也都有所差異.為能讓同一個Linux Kerne…
A context switch (also sometimes referred to as a process switch or a task switch) is the switching of the CPU (central processing unit) from one process or thread to another. A process (also sometimes referred to as a task) is an executing (i.e., ru…