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INTRODUCTION

This component demonstrates various features of the Intel I210 Ethernet controller. These features can be used for developing Audio/Video Bridging applications, Industrial Ethernet applications which require precise timing control over frame transmission, or test harnesses for measuring system latencies and sampling events.

This component - igb_avb - is limited to the Intel I210 Ethernet controller. The kernel module can be loaded in parallel to existing in-kernel igb modules which may be used on other supported Intel LAN controllers. Modifications are required to the in-kernel drivers if the existing in-kernel igb driver has support for the Intel I210.

BUILDING

The kernel igb module should be built which supports the latest Linux kernel 3.x PTP clock support. Unlike the standard igb driver, this version enables PTP by default (and will fail to build without kernel PTP support enabled).

RUNNING

To install the kernel mode driver, you must have root permissions. Typically, the driver is loaded by removing the currently running igb and running igb_avb: sudo rmmod igb sudo modprobe i2c_algo_bit sudo modprobe dca sudo modprobe ptp sudo insmod ./igb_avb.ko

Another option is to install the igb_avb driver in the "updates" directory which will override igb for the other drivers claiming the same device ID. This will allow the coexistence of igb and igb_avb. Copy igb_avb.ko to: sudo cp igb_avb.ko /lib/modules/uname -r/updates/ sudo depmod -a modprobe igb_avb

As the AVB Transmit queues (0,1) are mapped to a user-space application, typical LAN traffic must be steered away from these queues. The driver implements one method registering an ndo_select_queue handler to map traffic to queue[3]. Another possibly faster method uses the the transmit packet steering (XPS) functionality available since 2.6.35. An example script is below

#!/bin/bash

INTERFACE=p2p1 export INTERFACE

rmmod igb rmmod igb_avb insmod ./igb_avb.ko sleep 1 ifconfig $INTERFACE down echo 0 > /sys/class/net/$INTERFACE/queues/tx-0/xps_cpus echo 0 > /sys/class/net/$INTERFACE/queues/tx-1/xps_cpus echo f > /sys/class/net/$INTERFACE/queues/tx-2/xps_cpus echo f > /sys/class/net/$INTERFACE/queues/tx-3/xps_cpus ifconfig $INTERFACE up

You map also want to disable the network manager from 'managing' your interface. The easiest way is to find the interface configuration scripts on your distribution. On Fedora 18, these are located at /etc/sysconfig/network-scripts/ifcfg-. Edit the file to set 'BOOTPROTO=none'. This eliminates DHCP trying to configure the interface while you may be doing user-space application configuration.