High CPU usage on C881-K9 router

WilsonCheng · ‎11-22-2021

High CPU spikes occurred occasionally on C881-K9 router. After checked, the high cpu usage is caused by SNMP ENGINE. Does anyone know why SNMP ENGINE cause the high cpu usage and how to fix it?

Thank you.

CPU utilization for five seconds: 99%/0%; one minute: 19%; five minutes: 14%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
2 127092 929778 136 0.00% 0.01% 0.00% 0 Load Meter
6 8678540 873029 9940 0.00% 0.17% 0.16% 0 Check heaps
13 2288360 77438 29550 0.00% 0.03% 0.00% 0 Licensing Auto U
36 14276 4810310 2 0.08% 0.00% 0.00% 0 ARP Background
83 979432 81544 12011 0.00% 0.01% 0.00% 0 BGP Scanner
95 109816584 22922559 4790 1.49% 2.63% 2.69% 0 COLLECT STAT COU
99 323680 559037246 0 0.00% 0.12% 0.14% 0 Ethernet Msec Ti
117 144360 68886047 2 0.08% 0.03% 0.02% 0 VRRS Main thread
133 139424 135122810 1 0.00% 0.02% 0.01% 0 IPAM Manager
137 3310844 25594453 129 0.08% 0.18% 0.13% 0 IP Input
155 746352 15529026 48 0.00% 0.01% 0.00% 0 Spanning Tree
270 138064 68886040 2 0.00% 0.03% 0.02% 0 MMA DB TIMER
274 16312 8917272 1 0.08% 0.00% 0.00% 0 Timer Library
308 137348 68886030 1 0.00% 0.02% 0.01% 0 PERFMON ASYNC TI
309 139604 68886066 2 0.00% 0.03% 0.02% 0 MMA DP TIMER
320 512252 3869820 132 0.00% 0.03% 0.02% 0 Crypto IKMP
351 4728 968 4884 0.00% 0.70% 0.69% 10 SSH Process
393 1298212 203430 6381 0.00% 0.01% 0.00% 0 Per-minute Jobs
394 117752 4649541 25 0.08% 0.02% 0.00% 0 Per-Second Jobs
410 365588 276458667 1 0.00% 0.09% 0.08% 0 HSRP Common
412 255588 136364575 1 0.00% 0.06% 0.07% 0 PPP manager
413 203376 136364656 1 0.00% 0.04% 0.05% 0 PPP Events
420 878272 1059338468 0 0.00% 0.44% 0.47% 0 IP SLAs XOS Even
421 849088 1059232009 0 0.08% 0.42% 0.46% 0 IP SLAs Control
422 989804 1059755599 0 0.00% 0.44% 0.46% 0 IP SLAs Responde
423 715292 3558863 200 0.00% 0.01% 0.00% 0 IP SNMP
425 326368148 3761790 86761 97.08% 12.60% 7.96% 0 SNMP ENGINE

Leo Laohoo · ‎11-22-2021

Restart the SNMP process and see if the CPU utilization drops.

WilsonCheng · ‎11-22-2021

Hi Leo,

Thanks for suggestion. The high CPU usage occurred randomly, occasionally and only keeping high for a few seconds. I wonder if it is a problem or not.

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220000000000555552222288888999992222288888666666666655555555
100 *****
90 *****
80 *****
70 *****
60 **********
50 **********
40 ***************
30 ***************
20 ***** ***************
10 ************************************************************
0....5....1....1....2....2....3....3....4....4....5....5....6
0 5 0 5 0 5 0 5 0 5 0
CPU% per second (last 60 seconds)

Leo Laohoo · ‎11-23-2021

Please post the complete output to the command "sh version".

WilsonCheng · ‎11-23-2021

Cisco IOS Software, C800 Software (C800-UNIVERSALK9-M), Version 15.4(3)M8,
RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2017 by Cisco Systems, Inc.
Compiled Mon 31-Jul-17 06:05 by prod_rel_team

ROM: System Bootstrap, Version 15.4(1r)T1, RELEASE SOFTWARE (fc1)

router uptime is 7 weeks, 4 days, 23 hours, 1 minute
System returned to ROM by power-on
System restarted at 09:04:18 GMT Thu Sep 30 2021
System image file is "flash:c800-universalk9-mz.SPA.154-3.M8.bin"
Last reload type: Normal Reload
Last reload reason: power-on

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 C881-K9 (revision 1.0) with 488524K/35763K bytes of memory.
Processor board ID FGL211223D2
5 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 32 bits wide
255K bytes of non-volatile configuration memory.
250880K bytes of ATA System CompactFlash (Read/Write)

License Info:

License UDI:

-------------------------------------------------
Device# PID SN
-------------------------------------------------
*1 C881-K9 FGL211223D2

License Information for 'c800'
License Level: advipservices Type: Permanent
Next reboot license Level: advipservices

Configuration register is 0x2102