Catalyst C2950T-48 high cpu utilization

[new_yorik]

On catalyst C2950T-48-SI with c2950-i6q4l2-mz.121-22.EA1b.bin image, cpu utilization all the time at 20%.

16% of that taken with Calhoun LED Proc.

20 26528960 3298788 8042 16.71% 16.93% 16.97% 0 Calhoun LED Proc

Any idea why this happening?

[glen.grant]

This is not high , this normal for these switches . I can't tell you what the Calhoun process but what you are seeing is not high . The old 2924xl's would run 30% without anything attached so use that as comparison . If it was running say 50% then I would be more concerned .

[Kevin Dorrell]

Sorry to contradict you Glen, but I beg to differ. I have several 2912XLs and several 2950-12s doing the same job: as concentrators where the PC population in an office exceeds the number sockets. All the 2912XLs run a pretty constant 20%, but all the 2950-12s run typically 2-3%. I think the architecture is different.

But in his case he has a 2950, so I am inclined to believe it is worth investigating.

Kevin Dorrell

Luxembourg

[glen.grant]

It's possible but i'm looking at one of our 2950-48's and this has 3 switches hung underneath it with basically very few users yet on this stack and it is running 13% with the LED calhoun process leading the way . Our 24 port 2950's hung underneath the 2950-48 are only running about 2% so it appears there is some difference between the 24 port and 48 port on how they are allocating their resources.

[new_yorik]

Well, it seems to me like abnormal utilization, bacause none of my other 2950's doesn't have such high utilization, even with way higher traffic going thru it.

And on all of them Calhoun LED process using something between 0.00% to 0.40%

[majorward]

Is there latency on the devices connected to this switch?

[new_yorik]

nope

[Prashanth Krishnappa]

It is normal for this process to be a little higher.

The "Calhoun LED Proc" does a number of things on each physical port:

- Update statistics and error counters in port LED config, to update the

blink profile.

- For each port, calculate the next color to be displayed based on the

blink profile and the mode.

So, a 48G would be spending more cycles on LED process than 24G or a 12G but the CPU usage usually is not linear.

[new_yorik]

Okay, I have this 2950-48 and another 2950-24.

In 24 port switch all ports are connected and up, cpu load - 6% and Calhoun LED Proc use 0.57%.

In 48 port switch only 18 ports are connected and up, cpu load right now - 21% and Calhoun LED Proc use 16.28%.

It doesn't seems abnormal to you?

[peter.mainwaring]

Just for comparision, I've checked a few of our switches.

The c2950g-48's I checked all have cpu up around 34%, with the Calhoun LED proc seeming to account for a large part of that. Even on a switch with no users connected at all it is 25% (Calhoun LED proc again accounting for a lot of this).

By contrast, our c2950g-24's are much lower, with cpu at around 7% on a lightly loaded switch and 11% on a switch with most ports in use.

However, the actual network utilisation is quite low in all cases.

Pete

[new_yorik]

It doesn't look like a hardware or software bug to you?

Which IOS wersion are you using on this c2950g-48's switches?

[peter.mainwaring]

Yes - it does seem rather high, but as there have been no reports of performance problems, we haven't really followed it up.

We are a bit "down level" on these switches - they are running Version 12.1(13)EA1c. It will be interesting to see what happens when we bring the IOS up to date, but that won't be until after Xmas now.

Pete

[Prashanth Krishnappa]

It looks normal to me. As I said its not linear.

[new_yorik]

In my case it's linear, all the time on 19-20% (newer goes lower, some times little bit higher, but average is 19-20). Looks like plain line on my graph.

[Prashanth Krishnappa]

Normal again.. I meant to say its not linear between a 12 port or 24 port or 48 port versions. It might be 3-4% in 12 port and 24 port, does not mean it will be 6-8% in 48 port switch.