kernel idle process taking too much of cpu%

[Harsh Rao]

Hi people,

The system is GS160 with 10gb RAM and 7 cpus. It is Tru64 v5.1A pk5(with a couple of CSP's). The load average is going up, and simultaneously the memory that is free comes down. Memory utilization is ok, there are that many processes to consume the memory.

Main concern is the kernel idle process. What is the main function of that process. Why is it utilizing the cpu so much? Will changing the priority of the process help? is it possible to do so?? Is it ok if kernel idle process takes so much of cpu%??

The top o/p of the system:

load averages: 27.55, 27.45, 26.68 00:34:55
199 processes: 24 running, 62 waiting, 39 sleeping, 74 idle

Memory: Real: 3759M/4981M act/tot Virtual: 127M/8192M use/tot Free: 49M


PID USERNAME PRI NICE SIZE RES STATE TIME CPU COMMAND
524288 root 0 0 5912M 171M run 43.2H 106.30% kernel idle
775039 ora817 44 0 2911M 100M run 24:26 96.00% oracle
775174 ora817 44 0 2815M 9994K sleep 7:47 24.80% oracle
775588 ora817 44 0 2826M 19M sleep 6:53 22.60% oracle
775280 ora817 44 0 2827M 20M run 6:49 20.90% oracle
775221 ora817 44 0 2812M 6488K run 6:48 19.10% oracle
774024 ora817 44 0 2812M 7495K run 12:39 15.30% oracle
773211 ora817 44 0 2811M 6242K run 12:53 13.60% oracle
774047 ora817 44 0 2814M 8495K run 11:11 12.70% oracle
774079 ora817 44 0 2819M 14M run 16:53 12.60% oracle
772456 ora817 44 0 2811M 6184K run 11:14 12.60% oracle
773941 ora817 44 0 2817M 11M sleep 14:56 12.60% oracle
774028 ora817 44 0 2815M 9986K run 13:37 12.50% oracle
774007 ora817 44 0 2829M 23M run 18:48 12.40% oracle
773635 ora817 44 0 2813M 8192K run 8:41 12.40% oracle


Thankx in advance

[Michael Schulte zur Sur]

Hi,

read this thread:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=229167

I would guess, that kernel idle is the sum of idle times on all cpus, that's why it is so high.

Michael

[Hein van den Heuvel]

Pretty intense Oracle system usage there huh?
The 'kernel idle' is just accumulated idle time no? It is really idle, not eating memory access and so on

You could use dcpi / kprofile to 'see' what it is doing ( sysconfig -c pfm before first usage) in that idle loop(src/kernel/kern/sched_prim.c)

Can you provide some more details on that GS160? 10GB mem and 7 CPUs is kinda odd.
How many QBBs? Only 2 I hope!? How is the
memory divided? What is the final interleaving P00>>> SHOW MEMORY

The SGA is 2.8 GB no? Are you using GH or big-pages? You probably should as it has the potential of nicely reducing CPU time (by 5 - 10%?).

hth,
Hein.