How frequently does kernel update the /proc files?

geddysekar · 05-14-2010, 02:17 AM

Hi,

I am very new to the kernel world.

I want to know that how frequently the /proc files are updated by kernel?

My Kernel version : 2.6.18-8.1.8.el5

By,
Geddysekar

catkin · 05-14-2010, 02:28 AM

I can't cite an authoritative reference but believe they are updated when read.

syg00 · 05-14-2010, 02:29 AM

Every time you read them.
/proc is not a true filesystem, but a pseudo filesystem. The "files" are merely representations of kernel data, and are created as you read them.

geddysekar · 05-14-2010, 04:38 AM

Thanks for replying to the basic level question.

Once again Thanks..
GeddySekar

pixellany · 05-14-2010, 05:51 AM

I was not aware that the files were ever created---e.g. I don't believe the hard disk ever sees them.

My understanding is that you are see data structures in memory. The interface allows you to read (and--at your own risk--write) as if they were files.

(In *n(u|i)x, "everything is a file")

i92guboj · 05-14-2010, 06:04 AM

/proc is merely an interface to your kernel data structures in an fs-like fashion (in the purest *nix tradition), the files there do not exist in the same sense that a file exists in your hd, a pen or a ram drive. The data is provided as you ask for it, as real-time as the linux kernel can get.

syg00 · 05-14-2010, 06:32 AM

Kernel structures done't (automatically) have a procfs entry - they can be represented, but somebody has to provide the code to do create_proc_entry (and remove_proc_entry) - and provide read and write routines. And permissions.
Kobjects and sysfs are perhaps closer to what you're thinking pix. But someone still has to write the code.

bsat · 05-15-2010, 09:28 AM

In case are interested in seeing practically how the /proc entries are created ,read from and written to refer the following

http://tldp.org/LDP/lkmpg/2.6/html/c708.html