Cisco Systems UBR10012 Cpuhog Errors, Debug and System Messages, Exec and Virtual Exec Processes

Chapter 3 Troubleshooting PRE-1 Modules

Troubleshooting Common System Problems

CPUHOG Errors

The router displays a %SYS-3-CPUHOG error message when a process is using an excessive amount of processor cycles. For example, using the logging buffered command to allocate a significant amount of memory (for example, 200 MB) for log buffers could generate a %SYS-3-CPUHOG message, because allocating such an amount of memory requires a large amount of processor time.

For more information on what could cause this problem and how to resolve it, see the document What Causes %SYS-3-CPUHOG Messages, at the following URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00800a6ac4.sht ml

Debug and System Messages

A large volume of debugging messages or system messages can take a significant amount of processor time, because the PRE-1 module must spend a significant amount of time displaying these messages on the console port. In particular, this can happen when using the verbose or detail mode of a debug command, or if the debug command is dumping the contents of packets or packet buffers.

Use the following techniques to reduce the number of these messages:

1.Turn off the debugging messages by entering the no debug all command in privileged EXEC mode:

Router# no debug all

All possible debugging has been turned off

Router#

2.Disable console messages by using the no logging console command in global configuration mode:

Router# configure terminal

Router(config)# no logging console

Router(config)#

To keep the logging of console messages, but to limit the number of messages that can be displayed, use the logging rate-limitcommand. You can rate-limit all messages (including debug messages), or just the console messages, using one of the following commands:

Router(config)# logging rate-limit console number-of-messages-per-second

Router(config)# logging rate-limit all number-of-messages-per-second

3.If you have logged into the router using a Telnet connection, you can disable debug messages using the terminal default monitor command in privileged EXEC mode:

Router# terminal default monitor

Router#

Exec and Virtual Exec Processes

The Exec process is the Cisco IOS process that handles the TTY serial lines (console, auxiliary, asynchronous), and the Virtual Exec process handles the Virtual TTY (VTY) Telnet sessions. These processes run as mid-level processes, so if either one is exceptionally busy, it could generate a high CPU usage level.

Cisco uBR10012 Universal Broadband Router Troubleshooting Guide

OL-1237-01 3-11