High CPU Utilization

Posted on 2010-01-05
Medium Priority
Last Modified: 2012-05-08
MY router's CPU is hovering over 80%. I used "show proc cpu" command to find that out but I can't seem to identify which processes are causing this toll on the CPU. Can you provide some help in how to read the output of "show proc cpu" command?

Attached is the output of this command.

Question by:thunder8080
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Accepted Solution

satyasingh earned 600 total points
ID: 26188141
Did a quick look on cisco site and found the below, will look deeper and suggest shortly. Pls update if any of these help in b/w.


INFO: Total CPU Utilization is comprised of process and interrupt percentages.
  Total CPU Utilization: 85%
  Process Utilization: 4%
  Interrupt Utilization: 81%
These values are found on the first line of the output:
 CPU utilization for five seconds: x%/y%; one minute: a%; five minutes: b%
  Total CPU Utilization: x%
  Process Utilization: (x - y)%
  Interrupt Utilization: y%
Process Utilization is the difference between the Total and Interrupt (x and y).
The one and five minute utilizations are exponentially decayed averages (rather
than an arithmetic average), therefore recent values have more influence on the
calculated average.

WARNING: Total CPU Utilization is 85% for the past 5 seconds, which is high (>80%).
WARNING: Total CPU Utilization is 81% for the past 5 minutes, which is high (>80%).
NOTE: This is an exponentially decayed average rather than an arithmetic average,
therefore recent events have a greater effect than past events.
This can cause the following symptoms:
 - Input queue drops
 - Slow performance
 - Slow response in Telnet or unable to Telnet to the router
 - Slow response on the console
 - Slow or no response to ping
 - Router doesn't send routing updates
The following processes are causing excessive CPU usage:
 PID      CPU Time      Process
ERROR: No Processes were found having a CPU utilization greater than 10%
NOTE: If there are processes with a utilization greater than 10%, ensure that
there is no line wrapping as this will interfere with the analysis.
REFERENCE: For troubleshooting information, please visit Troubleshooting High
CPU Utilization on Cisco Routers

WARNING: Interrupt CPU Utilization is 81%, which is very high (>60%)
CPU interrupts are primarily caused by fast switching of traffic. Interrupts are
also generated any time a character is output from the console or auxiliary ports
of a router.
TRY THIS: One of the following may be causing this to happen:
 - Configured voice ports: Even if there is no traffic, software continues to
   monitor channel associated signaling (CAS).
 - Active ATM interfaces: Even with no traffic, ATM interfaces continue to send
   null cells (per ATM standard).
 - An inappropriate switching path is configured on the router. If you have a
   Cisco 7000 or Cisco 7500 series router, try improving its performance by
   using the 'ip route-cache {path}' command (path can be cef, distributed, or
   cbus, depending on the platform). If there are access lists linked to
   interfaces or if ip accounting is turned on, configure NetFlow switching
   using the 'ip route-cache flow' command.
 - The CPU is performing memory alignment corrections. If there are
   %ALIGN-3-CORRECT messages logged, then the high CPU utilization is caused by
   memory alignment corrections. Capture the output of the 'show align' command,
   decode the tracebacks and search for a bug in your version of IOS.
 - The router is overloaded with traffic. Use the 'show interfaces' command and
   paste into Output Interpreter to determine which interface is overloaded
 - There maybe a bug in the version of IOS running on the router. Check the
Bug Navigator   for a bug that reports similar symptoms in a similar environment.


Assisted Solution

satyasingh earned 600 total points
ID: 26188149
LVL 16

Expert Comment

ID: 26188199
what changes you made lately on your configuration ?

high CPU utilization most probably happened from configurations conflicts or multi routes
so, what's your router model and can you post your configuration , remove all passwords and real IPs ..

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Expert Comment

ID: 26188605
"no debug all"
LVL 10

Assisted Solution

lanboyo earned 400 total points
ID: 26188745
logging console critical
logging aux critical

If your hardware is cef capable

ip route-cache cef

- Are you running something the router would rather be done in hardware in such a way that it is being run by the processor...

Do you have any no ip route-cache commands on busy interfaces?  IPSEC tunnels without a vpn card?

Author Comment

ID: 26188845
Thanks for your comments:
@memo_tnt: No changes made recently
@JDLoaner: debug is off
@lanboyo: ip cef is already enabled.
LVL 16

Expert Comment

ID: 26188869
send more details about your router model ,, its memory/flash
number of connected clients/PCs..what services running behind it..
plus send sh int your WAN.interface results

also post running configuration

Expert Comment

ID: 26189013
sh ver
sh inv
sh run
sh arp
sh int

Expert Comment

ID: 26190144
following info needed

show ver
what type of bandwith?
show int

are u running any spanports/WCCP/Debug?

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