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Cisco 3945E - high CPU utilization

moskalevas
Level 1
Level 1

Hi, I have a problem with high utilization CPU on the cisco 3945E ISR (C3900-SPE250/K9 Version 15.1(1r)T4). When the router is working when there are no problems, the "show processes cpu sorted 5sec" command shows the following "CPU utilization for five seconds: 35% / 35%; one minute: 42%; five minutes: 42%", but at some intervals the load rises "five seconds: 99% / 98%; one minute: 89%; five minutes: 72%", I don’t see the processes that load the router, help me find the root of the problem, thanks.

8 Replies 8

Mark Malone
VIP Alumni
VIP Alumni
Hi
Can you post an example of the CPU output when its high , sounds as if its over loading and your getting interrupt traffic if you cant see process which is sent to the cpu and it spikes , this can be caused by several things but usually its a load issue on the router itself

You could also take the show tech and dump it into the Cisco cli analyzer it should tell you too whats triggering it


Possible Causes of High CPU Utilization Due to Interrupts

High CPU utilization on an interrupt level is primarily caused by packets handled on interrupt level. Interrupts are generated any time a character is output from the console or auxiliary ports of a router.

Universal Asynchronous Receiver/Transmitters (UARTs) are slow compared to the processing speed of the router, so it is unlikely, though possible, that console or auxiliary interrupts can cause a high CPU utilization on the router (unless the router has a large number of tty lines in use).

There are several reasons for high CPU utilization due to interrupts:

An inappropriate switching path is configured on the router

The CPU is performing alignment corrections

The router is overloaded with traffic

There's a bug in the Cisco IOS® software running on the router

Voice ports are configured on the router

There are active Asynchronous Transfer Mode (ATM) interfaces on the router

Too many packets are being punted from PXF to the Route Processor (RP)

Leo Laohoo
Hall of Fame
Hall of Fame

Post the complete output to the following commands: 

1.  sh version; and 

2.  sh proc cpu sort | e 0.00


Re: Cisco 3945E - high CPU utilization

show version
Cisco IOS Software, C3900e Software (C3900e-UNIVERSALK9-M), Version 15.2(4)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Fri 27-Jul-12 00:20 by prod_rel_team

ROM: System Bootstrap, Version 15.1(1r)T4, RELEASE SOFTWARE (fc1)

co-gw1 uptime is 13 weeks, 1 hour, 39 minutes
System returned to ROM by bus error at PC 0x200191D, address 0x200191D at 13:30:44 MSK Mon Jun 3 2019
System restarted at 13:12:52 MSK Mon Jun 3 2019
System image file is "flash:c3900e-universalk9-mz.SPA.152-4.M1.bin"
Last reload type: Normal Reload
Last reload reason: bus error at PC 0x200191D, address 0x200191D



This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

Cisco CISCO3945-CHASSIS (revision 1.0) with C3900-SPE250/K9 with 744448K/304128K bytes of memory.
Processor board ID FCZ1614221H
4 Gigabit Ethernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 72 bits wide with parity enabled.
256K bytes of non-volatile configuration memory.
250880K bytes of ATA System CompactFlash 0 (Read/Write)


License Info:

License UDI:

-------------------------------------------------
Device# PID SN
-------------------------------------------------
*0 C3900-SPE250/K9 FOC16014KS9



Technology Package License Information for Module:'c3900e'

-----------------------------------------------------------------
Technology Technology-package Technology-package
Current Type Next reboot
------------------------------------------------------------------
ipbase ipbasek9 Permanent ipbasek9
security securityk9 Permanent securityk9
uc None None None
data datak9 RightToUse datak9

Configuration register is 0x2102



show processes cpu sorted | e 0.00



normal:


CPU utilization for five seconds: 35%/34%; one minute: 51%; five minutes: 54%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
167 40908370 1731742305 23 0.19% 0.40% 0.42% 0 IP Input
86 30498890 7863891 3878 0.19% 0.27% 0.26% 0 Per-Second Jobs
236 4862010 62744490 77 0.11% 0.03% 0.04% 0 ADJ resolve proc
58 15624 905 17264 0.11% 2.78% 1.66% 578 SSH Process
33 17452124 535965292 32 0.07% 0.14% 0.14% 0 ARP Input
399 197279396 2966913935 0 0.03% 2.07% 2.34% 0 IP SNMP



show processes cpu sorted | e 0.00

high:


CPU utilization for five seconds: 96%/95%; one minute: 75%; five minutes: 65%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
167 40929790 1732056265 23 0.35% 0.47% 0.45% 0 IP Input
18 17163850 7839093 2189 0.31% 0.08% 0.09% 0 Environmental mo
86 30507904 7864938 3878 0.27% 0.25% 0.26% 0 Per-Second Jobs
398 3768902 3873607704 0 0.11% 0.03% 0.01% 0 IP SLAs XOS Even
236 4863638 62753690 77 0.07% 0.03% 0.03% 0 ADJ resolve proc
401 73062844 1485562545 49 0.03% 0.83% 0.95% 0 SNMP ENGINE
33 17458238 536044967 32 0.03% 0.14% 0.14% 0 ARP Input



or

show processes cpu sorted | e 0.00


CPU utilization for five seconds: 100%/99%; one minute: 86%; five minutes: 70%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
86 30513286 7864967 3879 0.16% 0.22% 0.25% 0 Per-Second Jobs
236 4865532 62753832 77 0.04% 0.02% 0.03% 0 ADJ resolve proc
Everyone's tags (0)

moskalevas
Level 1
Level 1
 

looks like interrupt traffic , you also had a crash recently

System returned to ROM by bus error at PC 0x200191D, address 0x200191D at 13:30:44 MSK Mon Jun 3 2019

is it possible to solve the problem?


I'm with @Mark Malone and I am more concerned at the recent crash.
My recommendation is to upgrade the IOS of the router first.

moskalevas
Level 1
Level 1
very few people worked during the weekend, there was no traffic, but the load was the same

03:37:02 PM Monday Sep 2 2019 MSK



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CPU% per second (last 60 seconds)



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CPU% per minute (last 60 minutes)
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0....5....1....1....2....2....3....3....4....4....5....5....6....6....7..
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CPU% per hour (last 72 hours)
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