High Proc CPU on 2621XM

Answered Question
Aug 31st, 2010

Hi all,

I have a 2621XM router with the following problem. It appears that the router operates at a high cpu level around 30/40 and goes to 100% most of the time. I´ve gone through the troubleshooting high cpu due to interrupts. The problem does not appear to be process related since there is no process that goes over 1%. And I have configured the profile terse parameters to see what interrupts may be hogging cpu time. I have no idea how to interpret the output. Also, made sure that ip cef was on and working according to others suggestions in and around the forum to be sure is not a packet forwarding problem or something like and it seems to be doing that ok.

The router is using 12.4-15T8 with 32mb and 256mb ram. Here is the profile terse not sure if anyone has some experience with these but I can´t figure out what is causing this cpu to be so taxed all the time.

The terse profile is included in an attachment on this post. Any help is very much appreciated.

Ron

I have this problem too.
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Correct Answer by Peter Paluch about 6 years 4 months ago

Ron,

Can you perhaps post the output of the show processes cpu sorted here? And also, is it possible for you to post the (sanitized) contents of your configuration?

In any case, it is possible that your router is simply handling too much traffic. The 2600XM is a software platform so every packet has to be routed in software even though the CEF provides an efficient way of doing that. Do you perform any monitoring on the amount of data flowing through your router?

Best regards,

Peter

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Correct Answer
Peter Paluch Tue, 08/31/2010 - 07:23

Ron,

Can you perhaps post the output of the show processes cpu sorted here? And also, is it possible for you to post the (sanitized) contents of your configuration?

In any case, it is possible that your router is simply handling too much traffic. The 2600XM is a software platform so every packet has to be routed in software even though the CEF provides an efficient way of doing that. Do you perform any monitoring on the amount of data flowing through your router?

Best regards,

Peter

Peter Paluch Wed, 09/01/2010 - 12:38

Hello Ron,

Sorry for replying lately, and thank you for sharing that information!

I have seen your config here briefly (you have removed it since then). What I can say is basically what the URL you referenced earlier suggests. Your router is, besides handling traffic, performing a couple of other operations (I saw ACLs, for example). A high amount of traffic with extensive operations over it will result in the CPU spending much of its time handling interrupts. Please note that the IP Input process is not involved in interrupt-context switching. The IP Input is concerned only with process switching.

Best regards,

Peter

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