Because debugging output is assigned high priority in the CPU process, it can render the system unusable.
For this reason, use
debug
commands only to troubleshoot specific problems or during troubleshooting sessions
with Cisco technical support staff. Moreover, it is best to use
debug
commands during periods of lower
network traffic and fewer users. Debugging during these periods decreases the likelihood that increased
debug
command processing overhead will affect system use.
Caution
Verifying Troubleshooting of the Software Configuration
Displaying OBFL Information
Example: Verifying the 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.
Device#
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
309 42289103 752750 56180 1.75% 1.20% 1.22% 0 RIP Timers
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.
Table 15: Troubleshooting CPU Utilization Problems
Corrective Action
Cause
Type of Problem
Determine the source of the network
packet. Stop the flow, or change the
switch configuration. See the section on
“Analyzing Network Traffic.”
The CPU is receiving too many
packets from the network.
Interrupt percentage value is
almost as high as total CPU
utilization value.
Identify the unusual event, and
troubleshoot the root cause. See the
section on “Debugging Active
Processes.”
One or more Cisco IOS process
is consuming too much CPU time.
This is usually triggered by an
event that activated the process.
Total CPU utilization is greater
than 50% with minimal time
spent on interrupts.
System Management Configuration Guide, Cisco IOS XE Gibraltar 16.10.x (Catalyst 9200 Switches)
257
Troubleshooting the Software Configuration
Verifying Troubleshooting of the Software Configuration