Strange High CPU on 2510 switches

[SweTwig]

Hi,

Over night some of our switches increesed their CPU usage from 5-10% to 50-70% and have staid there for a few days. It is 5 swtiches and they all started increese at the exact same time.

There is no increse in trafficflow, There was no change (this happnend on the night sun-mon). 
I have looked in the logs, cant se anything. 
I have investigated a possible loop but not able to find anything.

Spanning-tree is enabled on all switches.

Not sure where to look now, anyone have ideas on where to start?

[parnassus]

Start with checking show logging -r CLI command's output so you will be able to infer if there is any logs on the relevant issues' timeframe and infer about any possible relationship.

[SweTwig · Accepted solution]

Thanks for your suggestion.
The problem has been resolved. 

I had some work to do on one of the switches in the network (this switch did not have High CPU-load). So i disconnected it from the network, for a few minutes, triggering a STP-topology change. This somehow fixed the issue. Looking into my monitoring software, the CPU drops to normal at the exact moment I lost my first ping to the switch I was working on.

The high CPU-load dropped on all switched involved with this issue.... Not sure why and how but the issue is gone.