topic Process and high CPU in Operating System - HP-UX

Process and high CPU

Coolmar — Wed, 13 Apr 2005 14:11:35 GMT

Hi,

I have a process that is related to Oracle 10g OEM, that just sits up at 100% all the time. However, it doesn't seem to impact the system in any way. Should I be concerned about it though, or could TOP be giving incorrect information?

uptime:
1:07pm up 1:46, 3 users, load average: 0.44, 0.51, 0.47

top:
Cpu states:
CPU LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
0 0.91 14.9% 0.0% 71.3% 13.9% 0.0% 0.0% 0.0% 0.0%
3 0.14 0.0% 0.0% 2.0% 98.0% 0.0% 0.0% 0.0% 0.0%
4 0.31 3.0% 0.0% 12.9% 84.2% 0.0% 0.0% 0.0% 0.0%
--- ---- ----- ----- ----- ----- ----- ----- ----- -----
avg 0.45 6.0% 0.0% 29.0% 65.0% 0.0% 0.0% 0.0% 0.0%

Memory: 831384K (582868K) real, 5286372K (4437676K) virtual, 5868K free Page# 1/6

CPU TTY PID USERNAME PRI NI SIZE RES STATE TIME %WCPU %CPU COMMAND
3 pts/1 5300 oracle 152 20 290M 2000K run 91:56 100.30 100.12 emagent
3 ? 2 root 128 20 32K 32K sleep 4:18 2.33 2.33 vhand
3 ? 7396 oracle 152 20 1499M 25968K run 1:25 1.59 1.59 java
4 ? 7891 oracle 152 20 282M 8364K run 0:29 1.01 1.01 java
4 pts/1 7285 oracle 152 20 306M 21728K run 1:24 0.75 0.75 emagent
3 ? 2193 oracle 152 20 22620K 1888K run 0:05 0.39 0.38 opmn

Re: Process and high CPU

Bill Hassell — Wed, 13 Apr 2005 14:23:35 GMT

The following 4 commands:

while :
do
:
done

Will generate 100% CPU usage and won't impact anyone due to the way that HP-UX handles CPU timesharing. You could run a dozen of the above commands, see avg load over 10.0 and all 4 CPUs at 99% or higher. But if you look at the individual CPU stats from top, you'll see that it really isn't 100% CPU for emagent. Some of the load is %sys and another part is %nice. Otherwise, one of the CPU's would have a 1.0 load and 100% user value. The real question is for Oracle: should emagent consume lots of CPU time in a normal configuration?

top is a classic Unix tool but because it is a very basic tool, it is very easy to misinteret what it is saying. The real question is whether the system is now running slower (compared to what?) and whether overall throughput seems to be affected. It's useful to see processes that take a lot of RAM and/or CPU cycles, but if that is expected behavior, then all is well.

Re: Process and high CPU

Rick Garland — Wed, 13 Apr 2005 14:25:24 GMT

I would want to look at more info. How is the Oracle laid out? Are the disk accesses balanced out? How is the total IO? etc...

At first look, the system is OK. But this is a point in time look, how is it working over a day? Over a week? At month end?

Re: Process and high CPU

Coolmar — Wed, 13 Apr 2005 15:17:47 GMT

The system is load balanced and Oracle itself is great. It when we get into OEM, this process hangs around up a 100% cpu and wio but the system runs fine. So I guess it is just "supposed" to hang around up there I will assume.

Thanks!