Cisco Cisco IOS XE 3.5E Guide De Dépannage
Catalyst 3850 Series Switch High CPU Usage
Troubleshoot
Troubleshoot
Document ID: 117594
Contributed by Aninda Chatterjee and Yogesh Ramdoss, Cisco TAC
Engineers.
Apr 04, 2014
Engineers.
Apr 04, 2014
Contents
Introduction
Background Information
Case Study: Address Resolution Protocol (ARP) Interrupts
Step 1: Identify the Process that Consumes CPU Cycles
Step 2: Determine the CPU Queue that Causes the High CPU Usage Condition
Step 3: Dump the Packet Sent to the CPU
Step 4: Use FED Tracing
Sample Embedded Event Manager (EEM) Script for the Cisco Catalyst 3850 Series Switch
Related Information
Background Information
Case Study: Address Resolution Protocol (ARP) Interrupts
Step 1: Identify the Process that Consumes CPU Cycles
Step 2: Determine the CPU Queue that Causes the High CPU Usage Condition
Step 3: Dump the Packet Sent to the CPU
Step 4: Use FED Tracing
Sample Embedded Event Manager (EEM) Script for the Cisco Catalyst 3850 Series Switch
Related Information
Introduction
This document describes how to troubleshoot CPU usage concerns, primarily due to interrupts, on the new
Cisco IOS
Cisco IOS
®
−XE platform. Additionally, the document introduces several new commands on this platform that
are integral in order to troubleshoot such problems.
Background Information
It is important to understand how Cisco IOS−XE is built. With Cisco IOS−XE, Cisco has moved to a Linux
kernel and all of the subsystems have been broken down into processes. All of the subsystems that were inside
Cisco IOS before − such as the modules drivers, High Availability (HA), and so on − now run as software
processes within the Linux Operating System (OS). Cisco IOS itself runs as a daemon within the Linux OS
(IOSd). Cisco IOS−XE retains not only the same look and feel of the classic Cisco IOS, but also its operation,
support, and management.
kernel and all of the subsystems have been broken down into processes. All of the subsystems that were inside
Cisco IOS before − such as the modules drivers, High Availability (HA), and so on − now run as software
processes within the Linux Operating System (OS). Cisco IOS itself runs as a daemon within the Linux OS
(IOSd). Cisco IOS−XE retains not only the same look and feel of the classic Cisco IOS, but also its operation,
support, and management.
Here are some useful definitions:
Forwarding Engine Driver (FED): This is the heart of the Cisco Catalyst 3850 Series Switch and is
responsible for all hardware programming/forwarding.
responsible for all hardware programming/forwarding.
•
IOSd: This is the Cisco IOS daemon that runs on the Linux kernel. It is run as a software process
within the kernel.
within the kernel.
•
Packet Delivery System (PDS): This is the architecture and process of how packets are delivered to
and from various subsystem. As an example, it controls how packets are delivered from the FED to
the IOSd and vice versa.
and from various subsystem. As an example, it controls how packets are delivered from the FED to
the IOSd and vice versa.
•
Handle: A handle can be thought of as a pointer. It is a means to discover more detailed information
about specific variables that are used in the outputs that the box produces. This is similar to the
concept of Local Target Logic (LTL) indices on the Cisco Catalyst 6500 Series Switch.
about specific variables that are used in the outputs that the box produces. This is similar to the
concept of Local Target Logic (LTL) indices on the Cisco Catalyst 6500 Series Switch.
•