High CPU utilization 3560

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Oct 7th, 2009
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We are facing a weird problem of high CPU utilization on 3560 switch.

Even without connecting a single PC to switch, CPU utilization is showing 22 %.

Any particular reason for this?

Can configuration affect the CPU utilization even though there is no PC connected?

Please share the experience.

Any link on cisco.com is appreciable.

Thanks in advance


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pompeychimes Wed, 10/07/2009 - 20:03
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Configuration issues can indeed contribute to cpu util. I take it you've ran a "sh proc cpu" to determine what process or processes are utilizing the switch.

Post "sh proc cpu" output and config for further assitance.

bapatsubodh Thu, 10/08/2009 - 06:26
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here is the output of

show process cpu sorted

LEd process is taking up the CPU for 15 %.

Even though there nothing connected to it except console.

sh process cpu sorted

CPU utilization for five seconds: 22%/0%; one minute: 22%; five minutes: 22%

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

109 1353072 161887 8358 15.81% 15.86% 15.87% 0 Hulc LED Process

81 46240 8011 5772 0.63% 0.51% 0.54% 0 hpm counter proc

117 33966 1632 20812 0.47% 0.39% 0.37% 0 HQM Stack Proces

93 126 177 711 0.15% 0.12% 0.03% 0 Exec

(out put terminated )




pompeychimes Thu, 10/08/2009 - 06:47
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Below is an excerpt from this url http://www.cisco.com/en/US/products/hw/switches/ps607/products_tech_note09186a0080094e78.shtml

The common observation is that the CPU utilization output for the show processes cpu command on the 2900XL/3500XL switch shows a fairly high value when the switch is idle and has no active ports. When viewing the output of the show processes cpu command, the highest percentage processes are Port Status Proc (Port Status Process) and LED Control Proc (LED Control Process). It is normal behavior for these processes to be a high percentage of the total CPU utilization. These processes run constantly to maintain and monitor the status of the ports and the different LEDs available on the panel of the switch.

saif akbar Thu, 07/26/2012 - 08:21
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Hi All,

I had similar problem. After disabling (no shut) on unused ports, the CPU utilization went very low. ( from 62% to 11%). The HULC LED PROCESS went down from 10.67% to 0.43%.

Hope this will help you.



dsantana81 Thu, 07/26/2012 - 09:03
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It worked for me too! I did a no shut to all un-used ports and my cpu percentage significantly dropped. 60% was my CPU before I shutdown ports and it dropped to about 10% give and take. eventhough Cisco doesn't have a fix for this at this time and claims is a normal behavior I wasn't too happy with my switch using 60% CPU.




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