High CPU Utilization

Posted on 2010-01-05
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
    LVL 4

    Accepted Solution

    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.

    LVL 4

    Assisted Solution

    LVL 16

    Expert Comment

    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 ..

    LVL 4

    Expert Comment

    "no debug all"
    LVL 10

    Assisted Solution

    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

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

    Expert Comment

    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
    LVL 4

    Expert Comment

    sh ver
    sh inv
    sh run
    sh arp
    sh int
    LVL 8

    Expert Comment

    following info needed

    show ver
    what type of bandwith?
    show int

    are u running any spanports/WCCP/Debug?

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