High cpu utilisation for IDLE

[Francois Bariselle_3]

This is the result of top command on my K580 server on HP_UX 10.20 :

Load averages: 0.01, 0.01, 0.03
137 processes: 135 sleeping, 2 running
Cpu states:
CPU LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
0 0.00 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
1 0.00 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
2 0.04 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
3 0.00 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
--- ---- ----- ----- ----- ----- ----- ----- ----- -----
avg 0.01 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%

The IDLE is always 92-100% ! Is it ok...

Thanks in advance.
Frank

[Patrick Wallek]

The IDLE column means that it is not doing anything. I do find it hard to believe that it is 100% IDLE though. Unix should ALWAYS be doing something. I would expect to see, maybe, 99.5% IDLE, but not 100.

You might try installing the latest 'top' patch PHCO_22556.
http://www2.itrc.hp.com/service/patch/patchDetail.do?patchid=PHCO_22556&context=hpux:800:10:20

This patch has no dependencies and does NOT require a reboot.

[Jeff Schussele]

Hi Francois,

You can't get a system any quieter than that.
If the users aren't complaining about something not running - you're fine.

Rgds,
Jeff

[Sridhar Bhaskarla]

Hi Frank,

A best bet is to run some commands and see if the %idle changes. I would suggest to create a process that does some mathmatical calculations or compilation. Or atleast something like "sar -d 2 200".

If that doesn't change, then probably it may be a patch issue.

-Sri

[avsrini]

Hi Frank,
In ideal condition CPU IDLE state above 90% is ok. But 100% I am seeing for the first time. As sridhar suggested, I too think that there seems some problem with your top command utility.

what is the output of sar 1 3 output ?. If this shows different from your top output then it is confirmed, that you need to check your top command.

Is this server a production box ?. How many users are using this machine?.

Srini.

[Francois Bariselle_3]

This is a result of the command sar :

(tbmgr@quebec) /home/tbmgr% sar 1 3

HP-UX quebec B.10.20 U 9000/800 01/22/03

08:51:14 %usr %sys %wio %idle
08:51:15 0 0 0 100
08:51:16 0 1 0 99
08:51:17 0 0 0 100

Average 0 0 0 100

Only 14 user connected to this server by udp and rpc service. With connected or disconnected users, the IDLE is 100%

[Patrick Wallek]

I still think you need to load the latest 'top' patch, as referenced in my first post, and see if it makes a difference.

If not, then you just have a system that is not doing much. As long as the work is getting done I don't think there is a problem.

[Francois Bariselle_3]

Hi,

No change after install the latest 'top' patch on my server.

Frank.

[Paula J Frazer-Campbell]

Hi

100% idle is an average over all the processors in the system.

This is rounded up in the calculation - so ticking over with one processor doing the work at 99%

100+100+100+99 = 399

399/4 = 99.75, rounded up = 100% idle - not a problem.


Paula

[Chuck J]

92-100% idle is ok, infact it's pretty good. It means that the CPU is idling (like a car) and not doing alot of work.

Chuck J

[John Poff · Accepted solution]

Hi Frank,

We have some 10.20 K boxes. I looked at one of them [a K370] and here is the top output:

System: fduxok02 Wed Jan 22 08:40:49 2003
Load averages: 0.03, 0.03, 0.03
168 processes: 166 sleeping, 1 running, 1 zombie
Cpu states:
CPU LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
0 0.11 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
1 0.01 0.0% 0.0% 0.0% 100.0% 0.0% 0.0% 0.0% 0.0%
2 0.00 0.4% 0.0% 1.0% 98.6% 0.0% 0.0% 0.0% 0.0%
3 0.01 0.0% 0.0% 0.6% 99.4% 0.0% 0.0% 0.0% 0.0%
--- ---- ----- ----- ----- ----- ----- ----- ----- -----
avg 0.03 0.0% 0.0% 0.4% 99.6% 0.0% 0.0% 0.0% 0.0%


This box is in a MC/SG cluster and it has two small Oracle databases running on it. I'm not surprised that your box is 100% idle. Probably the system processes are running quickly enough that they just don't register completely. I wouldn't worry about it. The only person who should worry is the person who paid for four CPUs and probably doesn't need all of them. :)

JP