Description

High CPU behavior occurs when " show version detail " or “ show version detail |no-more ” is executed from the console, Telnet, or ssh.

This is specific to the following:

  • MX5
  • MX10
  • MX40
  • MX80
  • MX104

Symptoms

Running the "show version detail" or “show version detail | no-more” command generates high CPU usage. If executed with additional commands at the same time, the Routing Engine becomes overly busy and drops control of traffic packets such as OSPF, ISIS, etc.

In the example below, the output of the  run show chassis routing-engine  command reveals that available CPU was 96% before the command was executed, but was reduced to 5% after the command was executed.

CPU Utilization BEFORE executing run support information command:

user@router> show chassis routing-engine
Routing Engine status:
    Temperature                 52 degrees C / 125 degrees F
    CPU temperature             65 degrees C / 149 degrees F
    DRAM                      2048 MB (2048 MB installed)
    Memory utilization          37 percent
    5 sec CPU utilization:
      User                       1 percent
      Background                 0 percent
      Kernel                     3 percent
      Interrupt                  0 percent
      Idle                      96 percent
    1 min CPU utilization:
      User                       1 percent
      Background                 0 percent
      Kernel                     3 percent
      Interrupt                  0 percent
      Idle                      96 percent
*****

CPU Utilization AFTER executing run support information command:

user@router> show chassis routing-engine
Routing Engine status:
    Temperature                 52 degrees C / 125 degrees F
    CPU temperature             65 degrees C / 149 degrees F
    DRAM                      2048 MB (2048 MB installed)
    Memory utilization          37 percent
    5 sec CPU utilization:
      User                      35 percent
      Background                 0 percent
      Kernel                    60 percent
      Interrupt                  1 percent
      Idle                       5 percent
    1 min CPU utilization:
      User                       4 percent
      Background                 0 percent
      Kernel                     9 percent
      Interrupt                  0 percent
      Idle                      87 percent
    5 min CPU utilization:
      User                       1 percent
      Background                 0 percent
      Kernel                     4 percent
      Interrupt                  0 percent
 
*********

Solution

The " show version detail " command is known to increase the CPU while being run on these platforms. It is recommended to execute the "show version detail" command separate from an automation service that have additional operational commands. Instead, it is recommend to only use "show version".