High CPU utilization for DFC card (WS-X6716-10GE) on C6509-E

[PD92]

Hello Experts,

We are observing high cpu utilization only on the DFC card on a C6509 chassis. The utilization spikes and goes back to normal pretty quickly due to which even a EEM script in identifying a root cause is not feasible.

I am stuck upon identifying a root cause for the same. Any ideas/insights on the same will be appreciated.

Thanks in advance.

[balaji.bandi]

what is the version of code running on this kit, what you see when it spike show process cpu sorted | ex 0.00 (if you get a chance to capture this information ?)

Troubleshoot guide :

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/63992-6k-high-cpu.html

[Leo Laohoo]

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@PD92 wrote:

The utilization spikes and goes back to normal pretty quickly

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Possibly microbursts. 

Post the complete output to the following commands: 

sh version
sh interface <PORT>

We want to see the output from the active ports of that particular line card.

[MHM Cisco World]

if VSS SSO then I think the active DFC is syn with standby DFC. 

please check this point.

[Mohsin Alam]

In a Distributed Forwarding Card (DFC), the lcp schedular process that runs on a high CPU is not an issue and does not pose any problem to the operation. The LCP schedular is part of the firmware code. On all modules that do not require a DFC, the firmware runs on a specific processor called the Line Card Processor (LCP). This processor is used to program the ASIC hardware and to communicate to the central supervisor module.

When the lcp schedular is initiated, it makes use of all the process time available. But when a new process needs processor time, lcp schedular frees up process time for the new process. There is no impact to the performance of the system with regard to this high CPU utilization. The process simply grabs all unused CPU cycles, as long as no higher priority process requires them.

Ref: https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/63992-6k-high-cpu.html

## Make sure to mark post as helpful, If it resolved your issue. ##

[Giuseppe Larosa]

Hello @PD92 ,

post

show module

show ip route summary

just to see if your are not near the prefix limit capacity of the DFC

Hope to help

Giuseppe