proc hadoop

This article is also called "Linux Device Drivers", the fourth chapter of LDD3's Debuging Techniques's reading notes, but we are not limited to this content. 　　In linux, for example, to read the CPU, you can use cat/proc/cpuinfo. Through this, we can obtain the CPU by reading files in the program. This high-capacity and high-performance service is very commonly used, for example, when the cpu is greater than 60%, we will reject all business requests u

I. SummaryThe preceding section briefly introduces ProC configuration and Development in Windows. This time, we use the Linux platform to configure the Oracle ProC Development Environment (RedHat Linux 9 + Oracle 92) again ). ORACLE Database development (1). Configure and use ProC in Windows and ORACLE Database Development (2). Configure and use

Proc/pid/maps shows the memory regions and access rights mapped by the process. The operation set in the corresponding kernel is proc_pid_maps_op, and the specific export function is Show_map. A segment of the process's address space in the kernel is represented by a vm_area_struct struct, and all address spaces are stored in the Task->mm->mmap list.A file can be mapped to a memory area of the process, and the mapped file description characters in the

This time talk about the "/proc folder.The/proc folder is a special folder that is used to keep files related to the state of the system, and the files in this folder are only virtual files on memory.Some files under the/proc folder can reflect the running state of each process. So it's a very important folder to decide which Linux to run.With this folder, you ca

Build a Hadoop Client-that is, access Hadoop from hosts outside the Cluster Build a Hadoop Client-that is, access Hadoop from hosts outside the Cluster 1. Add host ing (the same as namenode ing ): Add the last line [Root @ localhost ~] # Su-root [Root @ localhost ~] # Vi/etc/hosts127.0.0.1 localhost. localdomain localh

I../PROC CATALOGUEThe/proc directory on a Linux system is a file system, the proc file system, unlike other common file systems, the/proc file system is a pseudo-file system that only exists in memory and does not occupy external memory space. It provides the interface for the kernel to communicate with the process in

Http://hi.baidu.com/zengzhaonong/blog/item/bd6c4be7a0bd3f36b8382061.html Get the symbolic address through/proc/kallsyms in the kernelLinux Kernel symbol table/proc/kallsyms Formation Process---------------------------------------------------------------------------./Scripts/kallsyms. C is responsible for generating system. Map./Kernel/kallsyms. C is responsible for generating/

The general form of Proc tabulate: (the subject is different from the freq process. Here is the table statement, not tables) 1 proc tabulate format = options;/* format = option to change the format of all cells in the table */2 var analysis-variable-list; 3 class classification-variable-list; /* the variables in the following Table statement must appear in the VaR statement or class in advance */4 Table Pag

First, the topicWrite a kernel module, add a directory hello to the/proc file system, and add a file in this directory to the world, the content of the file is Hello World. Kernel Version Requirements 2.6.18?Second, the experimental environmentPhysical host: Win7 64bit, i5 dual core, 8G memoryVirtual machines: Vmware Workstation 10.0.2Virtual Host: CentOs-5.11, kernel 2.6.18?Third, the experimental ideas struct proc_dir_entry? *create_proc_entry

When doing kernel-driven development, you can use the files under/proc to get the appropriate information for debugging.Most of the files under/proc are read-only, but for the completeness of the example, a write method is provided.Method One: Use Create_proc_entry to create the proc file (simple, but the write operation has the danger of buffer overflow);Method

When doing kernel-driven development, you can use the files under/proc to get the appropriate information for debugging.Most of the files under/proc are read-only, but for the completeness of the example, a write method is provided.Method One: Use Create_proc_entry to create the proc file (simple, but the write operation has the danger of buffer overflow);Method

We have had a special performance problem on a server where disk writes continue to be busy. Every 30 seconds, the server encounters a disk write activity spike that causes the request processing latency to be very large (more than 3 seconds). Later on the Internet to check the information, by adjusting the kernel parameters, the peak of the write activity is distributed to frequent multiple writes, each write less data. This can be used to flattened the peak write operation into multiple write

Disclaimer: You are free to reprint this article, but be sure to retain the integrity of this article.Author: Chamberlain JianEmail:zhangzijian@163.comDescription: The examples involved in this article are obtained under Fedora Core3.---------------------------------------------------------------------------------------------------/proc/net subdirectoriesThe files in this directory describe or modify the behavior of the networking code. You can set or

The kernel module traverses processes and task queues and saves them to the proc file. A module uses it to traverse the parent process and task queue of the current process, and output the traversal result to a proc file (traversal can start from the current process, the parent process traverses the initialization process, and the task queue can be traversed using the for_each_process macro ). The following

Free-m memory information query, cat/proc/cpuinfo cpu Information Query instance explanation, proccpuinfo Free cpu Information Query reference informationFree [root@VM_0_16_centos ~]# free -m total used free shared buffers cachedMem: 996 824 172 10 32 501-/+ buffers/cache: 289 706 Swap: 0 0 0 [root@VM_0_16_centos ~]# Formula: T

Jack: What does the device management mechanism of Linux implement look like, Kinky dragon?Me: In the 2.4 kernel, the main solution is DEVFS.Jack: I know. In 2.6, DEVFS has been replaced by Udev.Me: This is not accurate, is a layman to see the lively saying.Jack: What do you say?Me: Let me tell you about the origins of the proc file system. After listening, you will understand.Jack:proc file system? Across the.I: In a long long time ago, all the code

proc File System The/proc directory is the Linux proc file system, which contains the kernel configuration information, network configuration system, and the state of the process are all based on the PID clearly directory. In short, you can find the basic configuration of the kernel. Kernel update In the process of the kernel iteration, there are always some int

Ls/proc can see some digitally named folders, these numbers are pid[[email protected] proc]# CAT/PROC/1/STATM for the process487 185 133 31 0 67 0It is easy to return 7 sets of numbers, each of which is a page (common 4KB)respectively isSize: Task virtual address spaceResident: The size of the physical memory being usedShared: Share pagesTrs: The size of executab

--Manual release of Linux memory--/proc/sys/vm/drop_cachesThere are always a lot of friends in the memory management of Linux have doubts, the previous log does not seem to be able to clear everyone's doubts. In the new version of the core, it seems to provide a new solution to this problem, special turn out for you to refer to. Finally, I am enclosing my comments on this method, and I welcome all of you to discuss it together.When files are accessed

PRINTK will put the data in the kernel's 1 buffers, the other way to output information from the hardware, when we want to view the previous information can be used DMESG command to print out the information in the buffer. The DMESG command prints out the information from/proc/kmsg Proc is a virtual file system When the system starts, There's mount-a in there. A means that all the file systems are hooked