topic Re: Paging Rate in Operating System - Linux

Paging Rate

Shahul — Fri, 21 May 2004 06:09:57 GMT

Hi,

Can some one tell me about paging rate in Linux. I have HP, Sun and linux in an infrastructure. I have observed that the paging rate of Linux systems are high compared to other systems.

I have got average of 33 as paging rate for Linux servers. Is it looking bit high, I feel yes. Could you please throw some light on this.

TIA
Shahul

Re: Paging Rate

Mark Grant — Fri, 21 May 2004 06:14:46 GMT

Where are you getting this figure from? It's a bit difficult to say without further information.

However, I have never noticed linux "paging" more than anything else. It is worth pointing out that "paging in" is rather an important activity on a normal system. "paging out" to swap is the thing you have to watch.

Re: Paging Rate

Shahul — Fri, 21 May 2004 06:29:58 GMT

Hi,

pgpgin/S is almost zero, but pgpgout/S is around 50. I have got this paging rate by using some 3rd part performance test tool.

TIA
Shahul

Re: Paging Rate

Mark Grant — Fri, 21 May 2004 07:06:44 GMT

Well, paging out will probably be to swap. This would suggest that you do not have enough RAM in the machine.

Try a "vmstat 1" and look at the "si" and "so" fields. These give you the amount of memory swapped in kb/s.

Also, try "swapon -s" or "cat /proc/swaps" to see how much swap has been used since the last re-boot. Also, try "cat /proc/meminfo" and see the amount of free "RAM". If you are using swap, you'll probably need to increase the RAM in the machine.

Re: Paging Rate

Olivier Drouin — Fri, 21 May 2004 09:53:10 GMT

check this kerneltrap article
http://kerneltrap.org/node/view/3080?PHPSESSID=9530663ececa75286975d1de9cb60631