Troubleshootin CPU

[Nub65]

Hello,

We are experiencing high CPU usage on our Cisco device.

"show processes cpu sorted" does not indicate any major process usage.

Any ideas how can we troubleshoot such problems?

The Device is Cisco 2901. 

[marce1000]

 - Why do do you conclude then  that there is high CPU usage ?

    M.

[Rolf Fischer]

Hi,

we can see 93% CPU usage due to interrupts (only 96 - 93 = 3% are consumed by IOS processes).

Do you have CEF enabled?

This is a TS-Guide for 7500-series routers, it may help for your 2900 as well:

Troubleshooting High CPU Utilization Due to Interrupts 

[Nub65]

Hi Rolf,

Yes, CEF is enabled. Could you please clarify what interrupts are? Have not found any good explanation.

[Rolf Fischer]

Not sure if this is a good explanation, but interrupts cause the CPU to postpone other tasks in order to handle events that need immediate attention. There is always a certain level of interrupts on a router CPU, but 93% is by far too much, at least when it is permanently so high.

[Nub65]

Is there any way to check what kind of events cause this?

Have you ever experienced this and if so, how did you solve it?

Thank you for your time Rolf, highly appreciated.

[Rolf Fischer]

You're welcome. No, I haven't experienced this so far.
Perhaps the router is just overloaded by traffic?