proc freq

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

1)/proc/sys/vm/block_dumpThis file indicates whether block debug mode is turned on to record all read-write and dirty block writeback actions.Default setting: 0, disable block debug mode2)/proc/sys/vm/dirty_background_ratioThis file represents the percentage of dirty data that reaches the overall system memory, triggering the pdflush process to write dirty data back to disk.Default setting: 103)/

the returned value; no each! Method; Example: A = [1, 2, 3] B = a. collect {| x * 2} Puts ("--") Puts Puts ("-B -") Puts B C = a. collect! {| X * 2} Puts ("--") Puts -------------- Result ------------------ -- 1 3 -B- 2 6 -- 2 6 In additionHow can we iterate every character in a string? The first thing we need to do is to split the string using the split method, and then iterate; Example: A = "hello". each {| x | puts x} A = "hello". split (//). each {| x | puts x} ------------------- Result --

/Proc is a virtual file system, that is, the modification will be reinitialized after the reboot Provides process information, memory resources, hardware devices, kernel memory, and other information. For example: NIC:/proc/sys/vm/ipv4/ip_forward: control ip Forwarding Memory:/proc/sys/vm/drop_caches: Input 1 force the kernel to release some memory from the c

be the shell command printf, you want to see the library function printf What to do, then man 3 printf,that ' s OKThe following goes to today's point,/proc is a Linux system for our users can be used to access system-related data and information of a pseudo-file system, through which we can not only get to specify a process related information, but also to obtain the overall system operation and information. Because this article is about the tools of

Label:Pro*c is a high-level usage, and OCI is the basic use of Oracle How to compile a. pc file: proc code=cpp parse=none iname=filename.pc oname=filename.cpp First, I want to cover the header file #include this header file Secondly, we must define the struct SQLCA Sqlca before declaring the host variable; This variable. Three, all variables related to the Oracle database SQL statement must be declared as the host variable allocated space before they

First we need to figure out the proc mechanism, look at fs/proc/proc_misc.c this file, starting from the entry function:proc_misc_init (void)#ifdef CONFIG_PRINTK {struct proc_dir_entry *entry;entry = create_proc_entry ("Kmsg", S_irusr, proc_root);//Create a proc entry here Kmsgif (entry)entry->proc_fops = proc_kmsg_operations;//Set operation function, see note 1

1)/proc/sys/vm/block_dumpThis file indicates whether block debug mode is turned on to record all read-write and dirty block writeback actions.Default setting: 0, disable block debug mode2)/proc/sys/vm/dirty_background_ratioThis file represents the percentage of dirty data that reaches the overall system memory, triggering the pdflush process to write dirty data back to disk.Default setting: 103)/

Dynamically passes the physical address and size of the kernel space to user space. This article also demonstrates two common methods that can be used for communication between kernel space and user space: Proc file system and Mmap shared memory.The entire kernel module, when the module inserts, establishes the proc file, allocates the memory. When the module is unloaded, the content written by the user spa

when the Epoll handle is created, it will occupy an FD value, under Linux if look at the/proc/process id/fd/, is able to see this fd, so after using Epoll, you must call Close () closed, otherwise it may cause FD to be exhausted. The FD created by Epoll is:lrwx------1 root root 11:04 3-anon_inode:[eventpoll]This type of inode is created by Epoll.lrwx------1 root root 11:04 4-socket:[1126425]An article:It is well known that all open FD for this process

/** Procfs3.c-create a "file" In/proc, use the File_operation way* To manage the file.*/#include #include #include #include #define PROC_ENTRY_FILENAME "BUFFER2K"#define PROCFS_MAX_SIZE 2048/*** The buffer (2k) for this module**/static Char procfs_buffer[procfs_max_size];/*** The size of the data hold in the buffer**/static unsigned long procfs_buffer_size = 0;/*** The structure keeping information about The/proc