High CPU process on 3560G-48PS Switch

[siddiqirf]

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[Latchum Naidu]

Hi,

Cause:
Physical link flapping.

Action:
Review the syslog for a physical link losing and gaining connectivity.

Hulc LED Process is a process responsible for link status detection.
If there is SFP port in use, it might be a little bit high.

And also you can check if you hit the following bug.
CSCsi78581 Hulc LED Process uses 10-15% CPU on Catalyst 3750/3560.

Please rate the helpfull posts.
Regards,
Naidu.

[jaehun jeon]

Hi siddiqirf

Naidu say right solution then I add link that is same situation to posting context in forum.

The link is below

https://supportforums.cisco.com/thread/161063

HTH

[smogra]

HULC is a process responsible for link status detection. This task is performed after POST is done.

The LED process wakes up every 40ms to maintain the LED  states. Inside this infinite loop, it will

perform the following tasks.

1. Gather Status Information.

2. Calculate Display Mode.

3. Calculate LED States.

4. Calculate the Color.

5. Write the settings to LED register.

As Naidu said, when there is physical link flapping, you will see this process going high as it now has to do more work in order to  keep up the blinking LED status of ports. In case, your ports have been stable, look for the known caveat for the IOS version you are running. The most generic one has been mentioned by Naidu - CSCsi78581.

Cheers

Sweta

Please rate and mark the question answered if it helped you in resolving the issue.