High CPU usage

HaroldCalderon · ‎07-21-2020

Hello guys,

I have a problem sometimes my router reach 99% and the normal process is 20% so I dont know why sometimes hight to 99%

CPU utilization for five seconds: 99%/64%; one minute: 99%; five minutes: 99%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
96 24700015361623039662 1521 24.94% 26.82% 27.71% 0 IP Input
5 1049144100 101795034 10306 8.69% 9.58% 9.97% 0 Pool Manager
226 205256872 653890040 313 0.73% 0.79% 0.83% 0 IP NAT Ager
2 10570196 11599150 911 0.32% 0.10% 0.08% 0 Load Meter
17 138759700 193750243 716 0.24% 0.29% 0.28% 0 ARP Input
230 47643740 53699594 887 0.16% 0.10% 0.10% 0 IP SNMP
185 137883956 173424378 795 0.16% 0.18% 0.18% 0 Crypto PAS Proc
232 51885520 26823920 1934 0.16% 0.08% 0.08% 0 SNMP ENGINE
174 70592176 93717780 753 0.16% 0.22% 0.22% 0 Crypto Support
240 36158388 124309421 290 0.16% 0.08% 0.08% 0 IP-EIGRP: HELLO
61 9445712 231823739 40 0.08% 0.01% 0.00% 0 Netclock Backgro
121 48564 287666 168 0.08% 0.00% 0.00% 0 TCP Timer
198 11728500 289697258 40 0.08% 0.01% 0.00% 0 Atheros LED Ctro
13 1667824 57749328 28 0.00% 0.00% 0.00% 0 IPC Periodic Tim
14 1614012 57749342 27 0.00% 0.00% 0.00% 0 IPC Deferred Por
15 0 1 0 0.00% 0.00% 0.00% 0 IPC Seat Manager
11 26760 966526 27 0.00% 0.00% 0.00% 0 IPC Dynamic Cach
16 0 1 0 0.00% 0.00% 0.00% 0 IPC BackPressure
19 0 2 0 0.00% 0.00% 0.00% 0 ATM Idle Timer
20 0 2 0 0.00% 0.00% 0.00% 0 AAA high-capacit
12 0 1 0 0.00% 0.00% 0.00% 0 IPC Zone Manager
22 0 1 0 0.00% 0.00% 0.00% 0 Policy Manager
23 0 2 0 0.00% 0.00% 0.00% 0 DDR Timers
18 3282580 60218508 54 0.00% 0.00% 0.00% 0 ARP Background
21 0 1 0 0.00% 0.00% 0.00% 0 AAA_SERVER_DEADT
26 2372276 17339591 136 0.00% 0.00% 0.00% 0 HC Counter Timer
27 0 2 0 0.00% 0.00% 0.00% 0 Serial Backgroun
28 0 1 0 0.00% 0.00% 0.00% 0 RO Notify Timers
29 0 1 0 0.00% 0.00% 0.00% 0 RMI RM Notify Wa
24 0 2 0 0.00% 0.00% 0.00% 0 Entity MIB API
31 2147844 57991094 37 0.00% 0.00% 0.00% 0 GraphIt
32 0 2 0 0.00% 0.00% 0.00% 0 Dialer event33 0 1 0 0.00% 0.00% 0.00% 0 SERIAL A'detec

fas0/0

FastEthernet0/0 is up, line protocol is up
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 5/255, rxload 7/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 43w4d
Input queue: 23/75/4890363/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 3118000 bits/sec, 762 packets/sec
5 minute output rate 2055000 bits/sec, 836 packets/sec
3129874427 packets input, 977971593 bytes
Received 28659551 broadcasts, 0 runts, 0 giants, 430989 throttles
8427664 input errors, 0 CRC, 0 frame, 0 overrun, 8427664 ignored
0 watchdog
0 input packets with dribble condition detected
2672025210 packets output, 2084436041 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

Fas0/1

FastEthernet0/1 is up, line protocol is up

MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 6/255, rxload 3/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 43w5d
Input queue: 0/75/10545/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1402000 bits/sec, 810 packets/sec
5 minute output rate 2466000 bits/sec, 583 packets/sec
1813602017 packets input, 909749401 bytes
Received 77399079 broadcasts, 0 runts, 0 giants, 766 throttles
107855 input errors, 0 CRC, 0 frame, 0 overrun, 107855 ignored
0 watchdog
0 input packets with dribble condition detected
2009177570 packets output, 3892995344 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
713 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

ip CEF enable in general configuration

aaa session-id common
clock timezone UY -3
dot11 syslog
!
!
ip cef
!
!

interface FastEthernet0/0
description WAN a Internet
ip access-group EXTERNA in
ip access-group EXTERNA-OUT out
ip nat outside
no ip virtual-reassembly
ip tcp adjust-mss 1452
duplex auto
speed auto
crypto map VPN

interface FastEthernet0/1
ip nat inside
ip virtual-reassembly
duplex auto
speed auto

#show ip cef summary
IP CEF with switching (Table Version 35954), flags=0x0
217 routes, 0 reresolve, 0 unresolved (0 old, 0 new), peak 12
13 instant recursive resolutions, 0 used background process
217 leaves, 41 nodes, 75624 bytes, 28956 inserts, 28739 invalidations
0 load sharing elements, 0 bytes, 0 references
universal per-destination load sharing algorithm,
3(0) CEF resets, 7009 revisions of existing leaves
Resolution Timer: Exponential (currently 1s, peak 1s)
7009 in-place/0 aborted modifications
refcounts: 11560 leaf, 10752 node

Table epoch: 0 (217 entries at this epoch)

Adjacency Table has 127 adjacencies

Giuseppe Larosa · ‎07-21-2020

Hello @HaroldCalderon ,

>> CPU utilization for five seconds: 99%/64%; one minute: 99%; five minutes: 99%

you have 64% of CPU usage caused by I/O interrupts. This means many packets require special treatment and are process switched punted to the CPU.

see for example

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/troubleshooting/cpu_util.html?dtid=osscdc000283

Hope to help

Giuseppe

Joseph W. Doherty · ‎07-22-2020

The OP mentions using a "router", if so, the troubleshooting guide for a 3750 might be a bit misleading.

The following might be "better" (although not ideal, as the are for an old, large routers) troubleshooting guides:
https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/15095-highcpu.html
(and its reference to)
https://www.cisco.com/c/en/us/support/docs/routers/7500-series-routers/41160-highcpu-ip-input.html#ip_input

If would help if you would identify the router and its IOS version.

If a software based router, high CPU can simply reflect high traffic loading, but your ratio, between overall CPU and interrupt CPU isn't good, you have queued and/or dropped packets for your ingress queues, and your doing VPN with an "odd| adjust-MSS TCP size.

Leo Laohoo · ‎07-21-2020

@HaroldCalderon wrote:

FastEthernet0/0 is up, line protocol is up
 Full-duplex, 100Mb/s, 100BaseTX/FX
 8427664 input errors, 0 CRC, 0 frame, 0 overrun, 8427664 ignored

FastEthernet0/1 is up, line protocol is up
 Full-duplex, 100Mb/s, 100BaseTX/FX
 107855 input errors, 0 CRC, 0 frame, 0 overrun, 107855 ignored

Are the port configurations for Fa0/0 & Fa0/1 include speed and duplex hard coded?

Georg Pauwen · ‎07-22-2020

Hello,

in addition to the other remarks, post your full running configuration, we might be able to spot something...