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New Member

Very High CPU Utilisations

I have a few production switches (x2 multilayer, x1 layer 3) that have minimal CPU usage (at around 20%) but entering a show run will spike the CPU upwards of 90%. This is something i've not noticed before (anywhere), and was only noticed because I was investigating high CPU utilisations on the L3 switch. Is it normal for a switch to do this? The 2 multilayers have a moderately sized config and the L3 config is quite large, but contrasting this to a comparable sized text file on my workstation it only jumps the CPU to around 30%.

Thanks.           

10 REPLIES
Hall of Fame Super Bronze

Very High CPU Utilisations

Model and IOS version?

New Member

Very High CPU Utilisations

Multilayer is 3750x, IOS 15.1, L3 is a Catalyst 4000 and the IOS is 12.2.

Thanks.

Hall of Fame Super Bronze

Very High CPU Utilisations

Please post the 'show process cpu' output before and during the high CPU event.

New Member

Very High CPU Utilisations

The correct IOS for each are:

Multilayer: 12.2(53r)SER

L3: 12.2(33)SXH5

Before running a show run (on the L3):

CPU utilization for five seconds: 17%/9%; one minute: 9%; five minutes: 8%

PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process

303  27007170603414438445          0  3.59%  1.63%  1.59%   0 Port manager per

   8   9417002681831341989        514  1.03%  1.32%  1.00%   0 ARP Input

146   5074204803233069416          0  0.71%  0.64%  0.61%   0 IP Input

   5   402347664  25984773      15483  0.71%  0.29%  0.28%   0 Check heaps

  20   5651730643014806819          0  0.71%  0.25%  0.19%   0 IPC Seat Manager

199   287328804 205959437       1395  0.47%  0.42%  0.40%   0 CEF: IPv4 proces

153    49314648 120238459        410  0.15%  0.08%  0.06%   0 ARP HA

148   1485301921471432108        100  0.15%  0.12%  0.10%   0 ADJ resolve proc

151         168       141       1191  0.07%  0.11%  0.04%   3 Virtual Exec

192   112436416  52997820       2121  0.07%  0.09%  0.08%   0 IPC LC Message H

167    31255008  87977107        355  0.07%  0.07%  0.06%   0 DHCPD Receive

And after:

CPU utilization for five seconds: 71%/18%; one minute: 18%; five minutes: 10%

PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process

151        5640      4482       1258 46.00%  7.44%  1.61%   3 Virtual Exec

303  27007177403414442503          0  4.31%  1.66%  1.59%   0 Port manager per

   8   9417005081831342523        514  1.75%  1.14%  0.98%   0 ARP Input

146   5074207683233071038          0  0.55%  0.66%  0.62%   0 IP Input

199   287328920 205959480       1395  0.39%  0.42%  0.40%   0 CEF: IPv4 proces

148   1485302401471432555        100  0.07%  0.09%  0.09%   0 ADJ resolve proc

167    31255028  87977151        355  0.07%  0.05%  0.06%   0 DHCPD Receive

192   112436456  52997832       2121  0.07%  0.09%  0.08%   0 IPC LC Message H

I can see which process is causing the jump, I just don't know if this is normal!

Thanks for your time guys!

New Member

Very High CPU Utilisations

so it is Virtual Exec process, and I beleive you will not see the same issue when you use console/ssh

this is not normal, usually we see similar behavior when you generate the show tech, but show running should not cause high cpu. I beleive you can live with this, it will not cause any impact as this is not a high priority process, but if you like you can upgrade to a different version. good to check the bug list of a particular image before make an upgrade desicision so you will be aware if you are gonna hit any of the knwon bugs.

Regards

Hall of Fame Super Gold

Very High CPU Utilisations

Multilayer is 3750x, IOS 15.1, L3 is a Catalyst 4000 and the IOS is 12.2.

C'mon now, Edison is asking a legitimate question and your IOS is "15.1" and "12.2"?   Do you have any idea how long the list you've just provided????

Can you be more specific? 

New Member

Very High CPU Utilisations

I had already left the office and had to use my (hazy) memory!!

Hall of Fame Super Gold

Very High CPU Utilisations

I have a few production switches (x2 multilayer, x1 layer 3) that have minimal CPU usage (at around 20%) but entering a show run will spike the CPU upwards of 90%.

Forget it.  I'll make this nice and sweet.

You running Layer 3?  Use 12.2(55)SE7 or 12.2(55)SE8.  DO NOT, under any circumstances, use 15.0(1) and 15.0(2).

New Member

Re: Very High CPU Utilisations

Can you try to telnet and do "show runn", do the same thing but with ssh and from console
And please get the output of "show process cpu sorted | e 0.00"

Sent from Cisco Technical Support iPhone App

New Member

Very High CPU Utilisations

I have this problem 2 years back before with 2960's and 3750's eventually i found out that its just a IOS cosmetic bug.  The high CPU utilization will go upto 99% when you telnet into the machine.

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