Cisco IE 4000, Software Configuration Manual

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1047
Troubleshooting
Information for Troubleshooting
CPU Utilization
This section lists some possible symptoms that could be caused by the CPU being too busy and shows how to verify a
CPU utilization problem.
Table 71 on page 1047 lists the primary types of CPU utilization problems that you can identify.
It gives possible causes and corrective action with links to the Troubleshooting High CPU Utilization document on
Cisco.com.
Excessive CPU utilization might result in these symptoms, but the symptoms could also result from other causes.

Spanning tree topology changes

EtherChannel links brought down due to loss of communication

Failure to respond to management requests (ICMP ping, SNMP timeouts, slow Telnet or SSH sessions)

UDLD flapping

IP SLAs failures because of SLAs responses beyond an acceptable threshold

DHCP or IEEE 802.1x failures if the switch does not forward or respond to requests
Problem and Cause for High CPU Utilization
To determine if high CPU utilization is a problem, enter the show processes cpu sorted privileged EXEC command. Note
the underlined information in the first line of the output example.
Switch# show processes cpu sorted
CPU utilization for five seconds: 8%/0%; one minute: 7%; five minutes: 8%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
140 8820183 4942081 1784 0.63% 0.37% 0.30% 0 HRPC qos request
100 3427318 16150534 212 0.47% 0.14% 0.11% 0 HRPC pm-counters
192 3093252 14081112 219 0.31% 0.14% 0.11% 0 Spanning Tree
143 8 37 216 0.15% 0.01% 0.00% 0 Exec
...
<output truncated>
This example shows normal CPU utilization. The output shows that utilization for the last 5 seconds is 8%/0% , which has
this meaning:

The total CPU utilization is 8 percent, including both time running Cisco IOS processes and time spent handling
interrupts.

The time spent handling interrupts is zero percent.

For complete information about CPU utilization and how to troubleshoot utilization problems, see the Troubleshooting
High CPU Utilization document on Cisco.com.
Table 71 Troubleshooting CPU Utilization Problems
Type of Problem Cause Corrective Action
Interrupt percentage value is almost
as high as total CPU utilization value. The CPU is receiving too many packets
from the network. Determine the source of the network
packet. Stop the flow, or change the
switch configuration. See the section on
“Analyzing Network Traffic.”
Total CPU utilization is greater than
50% with minimal time spent on
interrupts. One or more Cisco IOS process is
consuming too much CPU time. This is
usually triggered by an event that
activated the process. Identify the unusual event, and
troubleshoot the root cause. See the
section on
“Debugging Active
Processes.”