Linux* Base Driver for the 10 Gigabit PCI Express Family of Adapters
====================================================================

June 17, 2008

Contents
========

- Important Note
- In This Release
- Identifying Your Adapter
- Building and Installation
- Command Line Parameters
- Additional Configurations
- Known Issues/Troubleshooting
- Support

IMPORTANT NOTE
==============

WARNING: The ixgbe driver compiles by default with the LRO (Large Receive
Offload) feature enabled. This option offers the lowest CPU utilization for
receives, but is completely incompatible with *routing/ip fowarding* and
*bridging*. If enabling ip forwarding or bridging is a requirement, it is
necessary to disable LRO using compile time options as noted in the LRO
section later in this document. The result of not disabling LRO when combined
with ip forwarding or bridging can be low throughput or even a kernel PANIC.

In This Release
===============

This file describes the ixgbe Linux* Base Driver for the 10 Gigabit PCI 
Express Family of Adapters.  This driver supports the 2.6.x kernel, and 
includes support for any Linux supported system, including Itanium(R)2, 
x86_64, i686, and PPC.

This driver is only supported as a loadable module at this time.  Intel is
not supplying patches against the kernel source to allow for static linking
of the driver. A version of the driver may already be included by your 
distribution and/or the kernel.org kernel. For questions related to hardware 
requirements, refer to the documentation supplied with your 10 Gigabit PCI
Express adapter.  All hardware requirements listed apply to use with Linux.

The following features are now available in supported kernels:
 - Native VLANs
 - Channel Bonding (teaming)
 - SNMP

Channel Bonding documentation can be found in the Linux kernel source:
/Documentation/networking/bonding.txt

Instructions on updating ethtool can be found in the section "Additional
Configurations" later in this document.


Identifying Your Adapter
========================

The following Intel network adapters are compatible with the drivers in this
release:

Controller        Adapter Name                      Physical Layer
----------        ------------                      --------------
82598EB     Intel(R) 10 Gigabit XF SR/LR   10G Base -SR  (850 nm optical fiber)
              Server Adapter               10G Base -LRM (850 nm optical fiber)
            Intel(R) 10 Gigabit XF SR      10G Base -LR (1310 nm optical fiber)
              Dual Port Server Adapters   
            Intel(R) 82598EB 10 Gigabit AF 
              Dual Port Network Connection
            Intel(R) 82598EB 10 Gigabit AF 
              Network Connection
            Intel(R) 82598EB 10 Gigabit AT 
              CX4 Network Connection         
            Intel(R) 10 Gigabit SR Dual
              Port Express Module

For more information on how to identify your adapter, go to the Adapter &
Driver ID Guide at:

    http://support.intel.com/support/network/sb/CS-012904.htm

For the latest Intel network drivers for Linux, refer to the following
website.  In the search field, enter your adapter name or type, or use the
networking link on the left to search for your adapter:

    http://downloadfinder.intel.com/scripts-df/support_intel.asp


Building and Installation
=========================

To build a binary RPM* package of this driver, run 'rpmbuild -tb
<filename.tar.gz>'.  Replace <filename.tar.gz> with the specific filename
of the driver.

NOTE: For the build to work properly, the currently running kernel MUST match
      the version and configuration of the installed kernel sources.  If you
      have just recompiled the kernel reboot the system now.

      RPM functionality has only been tested in RedHat distributions.

To manually build this driver:

1. Move the base driver tar file to the directory of your choice. For example,
   use /home/username/ixgbe or /usr/local/src/ixgbe.

2. Untar/unzip archive:

     tar zxf ixgbe-x.x.x.tar.gz

3. Change to the driver src directory:

     cd ixgbe-x.x.x/src/

4. Compile the driver module:

     make install

   The binary will be installed as:

     /lib/modules/[KERNEL_VERSION]/kernel/drivers/net/ixgbe/ixgbe.[k]o

   The install locations listed above are the default locations.  They might
   not be correct for certain Linux distributions. 

5. Load the module:
   For kernel 2.6.x, use the modprobe command:
     modprobe ixgbe <parameter>=<value>

   Note that for 2.6 kernels the insmod command can be used if the full
   path to the driver module is specified.  For example:

     insmod /lib/modules/<KERNEL VERSION>/kernel/drivers/net/ixgbe/ixgbe.ko

   With 2.6 based kernels also make sure that older ixgbe drivers are
   removed from the kernel, before loading the new module:

     rmmod ixgbe; modprobe ixgbe

6. Assign an IP address to the interface by entering the following, where
   x is the interface number:

     ifconfig ethx <IP_address> netmask <netmask>

7. Verify that the interface works. Enter the following, where <IP_address>
   is the IP address for another machine on the same subnet as the interface
   that is being tested:

     ping  <IP_address>

e1000-eedc@lists.sourceforge.net
To build ixgbe driver with DCA:
------------------------------

This example assumes the ioatdma and ixgbe sources are in /usr/src
 
1. Unpack the ioatdma source, build and install

     cd /usr/src
     tar zxf ioatdma-<ioat version>.tar.gz
     cd ioatdma-<ioat version>
     make
     make install
 
2. Unpack with ixgbe driver, build with DCA support and install
     
     cd /usr/src
     tar zxf ixgbe-<ixgbe version>.tar.gz
     cd ixgbe-<ixgbe-version>/src
     make install CLFLAGS_EXTRA="-DIXGBE_DCA -I/path/to/ioatdma-<ioat-version>
     /include"
    

Command Line Parameters
=======================

If the driver is built as a module, the  following optional parameters are
used by entering them on the command line with the modprobe command using
this syntax:

     modprobe ixgbe [<option>=<VAL1>,<VAL2>,...]

For example:

     modprobe ixgbe InterruptThrottleRate=16000,16000

The default value for each parameter is generally the recommended setting,
unless otherwise noted.


RSS - Receive Side Scaling (or multiple queues for receives)
------------------------------------------------------------
Valid Range: 0 - 16
0 = disables RSS
1 = enables RSS and sets the descriptor queue count to 16 or the number of
    online cpus, whichever is less.
2-16 = enables RSS, with 2-16 queues
Default Value: 1
RSS also effects the number of transmit queues allocated on 2.6.23 and
newer kernels with CONFIG_NETDEVICES_MULTIQUEUE set in the kernel .config file.


MQ - Multi Queue
----------------
Valid Range: 0, 1
0 = Disables Multiple Queue support
1 = Enabled Multiple Queue support (a prerequisite for RSS)
Default Value: 1


DCA - Direct Cache Access
-------------------------
Valid Range: 0, 1
0 = Disables DCA support in the driver
1 = Enables DCA support in the driver
Default Value: 1 (when IXGBE_DCA is enabled)
See the above instructions for enabling DCA.  If the driver is enabled for
DCA this parameter allows load-time control of the feature.


RxBufferMode
------------
Valid Range: 0 - 2
Default Value: 2
0 = Driver will use single buffer for Rx packets.
1 = Driver will use packet split mode for Rx. Packet header will be 
    received in header buffer and payload will be received in data buffer.
2 = Optimal mode. Driver will use single buffer mode for non-Jumbo 
    configurations and packet split mode for Jumbo configurations.


InterruptType
-------------
Valid Range: 0 - 2 0 = Legacy Int, 1 = MSI and 2 = MSI-X
Default Value: 2
Interrupt type controls allow load time control over the type of interrupt
registered for by the driver.  MSI-X is required for multiple queue
support, and some kernels and combinations of kernel .config options will
force a lower level of interrupt support.  'cat /proc/interrupts' will show
different values for each type of interrupt.    
  
  
InterruptThrottleRate
---------------------
Valid Range: 100 - 500,000 (0=off, 1=dynamic)
Default Value: 8000
     Interrupt Throttle Rate (interrupts/sec)
The ITR parameter controls how many interrupts each interrupt vector can
generate per second.  On MQ/RSS enabled kernels with MSI-X interrupts this
means that each RX vector can generate (by default) 8000 interrupts per second
and each TX vector can generate (by default) 4000 interrupts per second.
Increasing ITR lowers latency at the cost of increased CPU utilization, though
it may help throughput in some circumstances.
1 = Dynamic mode attempts to moderate interrupts per vector while maintaining
very low latency.  This can sometimes cause extra CPU utilization.  If planning
on deploying ixgbe in a latency sensitive environment please consider this
parameter.
0 = Setting InterruptThrottleRate to 0 turns off any interrupt moderation and
may improve small packet latency, but is generally not suitable for bulk 
throughput traffic due to the increased cpu utilization of the higher interrupt
rate.


LLI (Low Latency Interrupts)
---------------------------- 
LLI allows for immediate generation of an interrupt upon processing receive 
packets that match certain criteria as set by the parameters described below. 
LLI parameters are not enabled when Legacy interrupts are used. You must be 
using MSI or MSI-X (see cat /proc/interrupts) to successfully use LLI.

LLIPort
-------
Valid Range: 0 - 65535
Default Value: 0 (disabled)

  LLI is configured with the LLIPort command-line parameter, which specifies 
  which TCP port should generate Low Latency Interrupts.

  For example, using LLIPort=80 would cause the hardware to generate an 
  immediate interrupt upon receipt of any packet sent to TCP port 80 on the 
  local machine.

WARNING: Enabling LLI can result in an excessive number of interrupts/second 
that may cause problems with the system and in some cases may cause a kernel 
panic.


LLIPush
-------
Valid Range: 0-1
Default Value: 0 (disabled)

  LLIPush can be set to be enabled or disabled (default). It is most 
  effective in an environment with many small transactions.
  NOTE: Enabling LLIPush may allow a denial of service attack.


LLISize
-------
Valid Range: 0-1500
Default Value: 0 (disabled)

  LLISize causes an immediate interrupt if the hardware receives a packet 
  smaller than the specified size.


Additional Configurations
=========================

  Configuring the Driver on Different Distributions
  -------------------------------------------------
  Configuring a network driver to load properly when the system is started is
  distribution dependent. Typically, the configuration process involves adding
  an alias line to /etc/modules.conf or /etc/modprobe.conf as well as editing
  other system startup scripts and/or configuration files.  Many popular Linux
  distributions ship with tools to make these changes for you.  To learn the
  proper way to configure a network device for your system, refer to your
  distribution documentation.  If during this process you are asked for the
  driver or module name, the name for the Linux Base Driver for the Intel
  10GbE PCI Express Family of Adapters is ixgbe.

  Viewing Link Messages
  ---------------------
  Link messages will not be displayed to the console if the distribution is
  restricting system messages. In order to see network driver link messages on
  your console, set dmesg to eight by entering the following:

       dmesg -n 8

  NOTE: This setting is not saved across reboots.


  Jumbo Frames
  ------------
  The driver supports Jumbo Frames for all adapters. Jumbo Frames support is
  enabled by changing the MTU to a value larger than the default of 1500.
  The maximum value for the MTU is 16110.  Use the ifconfig command to
  increase the MTU size.  For example:

        ifconfig ethx mtu 9000 up

  The maximum MTU setting for Jumbo Frames is 16110.  This value coincides
  with the maximum Jumbo Frames size of 16128. This driver will attempt to
  use multiple page sized buffers to receive each jumbo packet.  This
  should help to avoid buffer starvation issues when allocating receive
  packets.


  Ethtool
  -------
  The driver utilizes the ethtool interface for driver configuration and
  diagnostics, as well as displaying statistical information.  Ethtool
  version 3.0 or later is required for this functionality.

  The latest release of ethtool can be found from
  http://sourceforge.net/projects/gkernel.


  NAPI
  ----
  NAPI (Rx polling mode) is supported in the ixgbe driver.  NAPI is enabled
  or disabled based on the configuration of the kernel.  To override the 
  default, use the following compile-time flags.

  To enable NAPI, compile the driver module, passing in a configuration option:

            make CFLAGS_EXTRA=-DIXGBE_NAPI install
  NOTE: This will not do anything if NAPI is disabled in the kernel. 

  To disable NAPI, compile the driver module, passing in a configuration 
  option:

            make CFLAGS_EXTRA=-DIXGBE_NO_NAPI install


  See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.


  LRO
  ---
  Large Receive Offload (LRO) is a technique for increasing inbound throughput
  of high-bandwidth network connections by reducing CPU overhead. It works by
  aggregating multiple incoming packets from a single stream into a larger 
  buffer before they are passed higher up the networking stack, thus reducing
  the number of packets that have to be processed. LRO combines multiple 
  Ethernet frames into a single receive in the stack, thereby potentially 
  decreasing CPU utilization for receives. 

  IXGBE_NO_LRO is a compile time flag. The user can enable it at compile
  time to remove support for LRO from the driver. The flag is used by adding 
  CFLAGS_EXTRA="-DIXGBE_NO_LRO" to the make file when it's being compiled. 

     make CFLAGS_EXTRA="-DIXGBE_NO_LRO" install

  You can verify that the driver is using LRO by looking at these counters in 
  Ethtool:

  lro_flushed - the total number of receives using LRO.
  lro_coal - counts the total number of Ethernet packets that were combined.


  rx_dropped_backlog
  ------------------
  When in a non-Napi (or Interrupt) mode, this counter indicates that the stack
  is dropping packets. There is an adjustable parameter in the stack that allows
  you to adjust the amount of backlog. We recommend increasing the 
  netdev_max_backlog if the counter goes up.

  # sysctl -a |grep netdev_max_backlog
  net.core.netdev_max_backlog = 1000

  # sysctl -e net.core.netdev_max_backlog=10000
  net.core.netdev_max_backlog = 10000


  Flow Control
  ------------
  Flow control is disabled by default. If you want to enable and have a flow 
  control capable link partner, use Ethtool:

     ethtool -A eth? autoneg off rx on tx on

  FCOE
  ----
  This release of the ixgbe driver contains new code to enable users to use 
  Fiber Channel over Ethernet (FCoE) and Data Center Bridging (DCB) 
  functionality that is supported by the 82598-based hardware.  This code has
  no default effect on the regular driver operation, and configuring DCB and 
  FCoE is outside the scope of this driver README. Refer to 
  http://www.open-fcoe.org/ for FCoE project information and contact 
  e1000-eedc@lists.sourceforge.net for DCB information.


Known Issues/Troubleshooting
============================


  NOTE: After installing the driver, if your Intel Network Connection is not 
  working, verify in the "In This Release" section of the readme that you have 
  installed the correct driver.


  MSI-X Issues with 82598-based Intel(R)10GbE-LR/LRM/SR/AT Server Adapters
  ------------------------------------------------------------------------
  Kernel panics and instability may be observed on some platforms when 
  running 82598-based Intel(R) 10GbE-LR/LRM/SR/AT Server Adapters with 
  MSI-X in a stress environment. Symptoms of this issue include observing 
  "APIC 40 Error" or "no irq handler for vector" error messages on the 
  console or in "dmesg."

  If such problems are encountered, you may disable the irqbalance daemon. 
  If the problems persist, compile the driver in pin interrupt mode, do 
  	make CFLAGS_EXTRA=-DDISABLE_PCI_MSI
 
  Or you can load the module with modprobe ixgbe InterruptType=0

                         
  Driver Compilation
  ------------------
  When trying to compile the driver by running make install, the following
  error may occur:

      "Linux kernel source not configured - missing version.h"

  To solve this issue, create the version.h file by going to the Linux source
  tree and entering:

      make include/linux/version.h.


  Do Not Use LRO When Routing Packets
  -----------------------------------
  Due to a known general compatibility issue with LRO and routing, do not use
  LRO when routing packets. 


  Jumbo Frames System Requirement
  -------------------------------
  Memory allocation failures have been observed on Linux systems with 64 MB
  of RAM or less that are running Jumbo Frames.  If you are using Jumbo
  Frames, your system may require more than the advertised minimum
  requirement of 64 MB of system memory.


  Performance Degradation with Jumbo Frames
  -----------------------------------------
  Degradation in throughput performance may be observed in some Jumbo frames
  environments.  If this is observed, increasing the application's socket buffer
  size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help.
  See the specific application manual and /usr/src/linux*/Documentation/
  networking/ip-sysctl.txt for more details.


  Multiple Interfaces on Same Ethernet Broadcast Network
  ------------------------------------------------------
  Due to the default ARP behavior on Linux, it is not possible to have
  one system on two IP networks in the same Ethernet broadcast domain
  (non-partitioned switch) behave as expected.  All Ethernet interfaces
  will respond to IP traffic for any IP address assigned to the system.
  This results in unbalanced receive traffic.

  If you have multiple interfaces in a server, do either of the following:

  - Turn on ARP filtering by entering:
      echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter

  - Install the interfaces in separate broadcast domains - either in
    different switches or in a switch partitioned to VLANs.


  UDP Stress Test Dropped Packet Issue
  --------------------------------------
  Under small packets UDP stress test with 10GbE driver, the Linux system
  may drop UDP packets due to the fullness of socket buffers. You may want
  to change the driver's Flow Control variables to the minimum value for
  controlling packet reception.

  Or you can increase the kernel's default buffer sizes for udp by changing 
  the values in /proc/sys/net/core/rmem_default and rmem_max


  Unplugging network cable while ethtool -p is running
  ----------------------------------------------------
  In kernel versions 2.5.50 and later (including 2.6 kernel), unplugging 
  the network cable while ethtool -p is running will cause the system to 
  become unresponsive to keyboard commands, except for control-alt-delete.  
  Restarting the system appears to be the only remedy.


  Cisco Catalyst 4948-10GE port resets may cause switch to shut down ports
  ------------------------------------------------------------------------
  82598-based hardware can re-establish link quickly and when connected to some 
  switches, rapid resets within the driver may cause the switch port to become 
  isolated due to "link flap". This is typically indicated by a yellow instead
  of a green link light. Several operations may cause this problem, such as 
  repeatedly running ethtool commands that cause a reset.  

  A potential workaround is to use the Cisco IOS command "no errdisable detect 
  cause all" from the Global Configuration prompt which enables the switch to 
  keep the interfaces up, regardless of errors.


Support
=======

For general information, go to the Intel support website at:

    http://support.intel.com

or the Intel Wired Networking project hosted by Sourceforge at:

    http://sourceforge.net/projects/e1000

If an issue is identified with the released source code on the supported
kernel with a supported adapter, email the specific information related
to the issue to e1000-devel@lists.sf.net


License
=======

Intel 10 Gigabit PCI Express Linux driver.
Copyright(c) 1999 - 2007 Intel Corporation.

This program is free software; you can redistribute it and/or modify it
under the terms and conditions of the GNU General Public License,
version 2, as published by the Free Software Foundation.

This program is distributed in the hope it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

The full GNU General Public License is included in this distribution in
the file called "COPYING".


Trademarks
==========

Intel, Itanium, and Pentium are trademarks or registered trademarks of
Intel Corporation or its subsidiaries in the United States and other
countries.

* Other names and brands may be claimed as the property of others.
