Just wondering if it can cause slow down on my production network since 1 out of 4 cpu is on 99% utilization?
but the rest still quite low. See screenshot for your reference.
Model Number : WS-C3850-24T
That is not normal and can eventually cause problems. I would open a ticket with TAC and have them investigate the high CPU utilization. It may a bug in the version of the software you are running.
Which Is the IOS Version you are running?
There had been Some instances of buggy behaviour on 3850 running 3.6.x code and 3.7.x code.
there could be a hit to these below
check with following
sh proc cpu sort | e 0.0
! check if you are seeing fed, pdsd, stack-mgr as top processes
sh proc cpu det proc fed sort | e 0.0
! check if you are seeing fed-ots-main ,fed as top processes
!check with these output continuesly for the cpu queues traffic punting
show platform punt statistics port-asic 0 cpuq -1 direction rx | beg CPU_Q_FORUS_TRAFFIC
If the above is the case, consider upgrading the switch.
you can also refer to following if its specific packet which is hitting CPU
Cisco IOS Software, IOS-XE Software, Catalyst L3 Switch Software (CAT3K_CAA-UNIV ERSALK9-M), Version 03.06.05E RELEASE SOFTWARE (fc2)
You are probably hitting one of the issues that Utkarsh mentioned:
It is not fixed until 3.6.6. I believe 3.6.10 is out if you want to stay on the same train or move to the recommended code of 16.6.5. I would upgrade this device when you get a chance.
Hope that helps!
I don't think it will cause the network super slow as only one core at 99%, And the rest of core are below 20%, It could be due to one single instance. </p><p class="p1">But i would say keep eyes on CPU if it constantly shows 99% even-though for one core, In that case you might need to look, if it due to legitimate reason or is something else which may eventually impact other core as well and ended up with slow network or other intrusive impacts.