07-10-2013 08:36 AM - edited 03-04-2019 08:25 PM
I have a few production switches (x2 multilayer, x1 layer 3) that have minimal CPU usage (at around 20%) but entering a show run will spike the CPU upwards of 90%. This is something i've not noticed before (anywhere), and was only noticed because I was investigating high CPU utilisations on the L3 switch. Is it normal for a switch to do this? The 2 multilayers have a moderately sized config and the L3 config is quite large, but contrasting this to a comparable sized text file on my workstation it only jumps the CPU to around 30%.
Thanks.
07-10-2013 08:50 AM
Model and IOS version?
07-10-2013 09:58 AM
Multilayer is 3750x, IOS 15.1, L3 is a Catalyst 4000 and the IOS is 12.2.
Thanks.
07-10-2013 10:12 AM
Please post the 'show process cpu' output before and during the high CPU event.
07-11-2013 12:26 AM
The correct IOS for each are:
Multilayer: 12.2(53r)SER
L3: 12.2(33)SXH5
Before running a show run (on the L3):
CPU utilization for five seconds: 17%/9%; one minute: 9%; five minutes: 8%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
303 27007170603414438445 0 3.59% 1.63% 1.59% 0 Port manager per
8 9417002681831341989 514 1.03% 1.32% 1.00% 0 ARP Input
146 5074204803233069416 0 0.71% 0.64% 0.61% 0 IP Input
5 402347664 25984773 15483 0.71% 0.29% 0.28% 0 Check heaps
20 5651730643014806819 0 0.71% 0.25% 0.19% 0 IPC Seat Manager
199 287328804 205959437 1395 0.47% 0.42% 0.40% 0 CEF: IPv4 proces
153 49314648 120238459 410 0.15% 0.08% 0.06% 0 ARP HA
148 1485301921471432108 100 0.15% 0.12% 0.10% 0 ADJ resolve proc
151 168 141 1191 0.07% 0.11% 0.04% 3 Virtual Exec
192 112436416 52997820 2121 0.07% 0.09% 0.08% 0 IPC LC Message H
167 31255008 87977107 355 0.07% 0.07% 0.06% 0 DHCPD Receive
And after:
CPU utilization for five seconds: 71%/18%; one minute: 18%; five minutes: 10%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
151 5640 4482 1258 46.00% 7.44% 1.61% 3 Virtual Exec
303 27007177403414442503 0 4.31% 1.66% 1.59% 0 Port manager per
8 9417005081831342523 514 1.75% 1.14% 0.98% 0 ARP Input
146 5074207683233071038 0 0.55% 0.66% 0.62% 0 IP Input
199 287328920 205959480 1395 0.39% 0.42% 0.40% 0 CEF: IPv4 proces
148 1485302401471432555 100 0.07% 0.09% 0.09% 0 ADJ resolve proc
167 31255028 87977151 355 0.07% 0.05% 0.06% 0 DHCPD Receive
192 112436456 52997832 2121 0.07% 0.09% 0.08% 0 IPC LC Message H
I can see which process is causing the jump, I just don't know if this is normal!
Thanks for your time guys!
07-11-2013 12:41 AM
so it is Virtual Exec process, and I beleive you will not see the same issue when you use console/ssh
this is not normal, usually we see similar behavior when you generate the show tech, but show running should not cause high cpu. I beleive you can live with this, it will not cause any impact as this is not a high priority process, but if you like you can upgrade to a different version. good to check the bug list of a particular image before make an upgrade desicision so you will be aware if you are gonna hit any of the knwon bugs.
Regards
07-10-2013 03:07 PM
Multilayer is 3750x, IOS 15.1, L3 is a Catalyst 4000 and the IOS is 12.2.
C'mon now, Edison is asking a legitimate question and your IOS is "15.1" and "12.2"? Do you have any idea how long the list you've just provided????
Can you be more specific?
07-11-2013 12:23 AM
I had already left the office and had to use my (hazy) memory!!
07-10-2013 04:52 PM
I have a few production switches (x2 multilayer, x1 layer 3) that have minimal CPU usage (at around 20%) but entering a show run will spike the CPU upwards of 90%.
Forget it. I'll make this nice and sweet.
You running Layer 3? Use 12.2(55)SE7 or 12.2(55)SE8. DO NOT, under any circumstances, use 15.0(1) and 15.0(2).
07-10-2013 03:50 PM
Can you try to telnet and do "show runn", do the same thing but with ssh and from console
And please get the output of "show process cpu sorted | e 0.00"
Sent from Cisco Technical Support iPhone App
07-10-2013 09:03 PM
I have this problem 2 years back before with 2960's and 3750's eventually i found out that its just a IOS cosmetic bug. The high CPU utilization will go upto 99% when you telnet into the machine.
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