e1000.txt: Update e1000 documentation

Linux* Base Driver for the Intel(R) PRO/1000 Family of Adapters

===============================================================

September 26, 2006

Intel Gigabit Linux driver.

Copyright(c) 1999 - 2010 Intel Corporation.

Contents

========

- In This Release

- Identifying Your Adapter

- Building and Installation

- Command Line Parameters

- Speed and Duplex Configuration

- Additional Configurations

- Known Issues

- Support

In This Release

===============

This file describes the Linux* Base Driver for the Intel(R) PRO/1000 Family

of Adapters.  This driver includes support for Itanium(R)2-based systems.

For questions related to hardware requirements, refer to the documentation

supplied with your Intel PRO/1000 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

The driver information previously displayed in the /proc filesystem is not

supported in this release.  Alternatively, you can use ethtool (version 1.6

or later), lspci, and ifconfig to obtain the same information.

Instructions on updating ethtool can be found in the section "Additional

Configurations" later in this document.

NOTE: The Intel(R) 82562v 10/100 Network Connection only provides 10/100

support.

Identifying Your Adapter

========================

For more information on how to identify your adapter, go to the Adapter &

Driver ID Guide at:

    http://support.intel.com/support/network/adapter/pro100/21397.htm

    http://support.intel.com/support/go/network/adapter/idguide.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

    http://support.intel.com/support/go/network/adapter/home.htm

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 e1000 [<option>=<VAL1>,<VAL2>,...]

For example, with two PRO/1000 PCI adapters, entering:

     modprobe e1000 TxDescriptors=80,128

loads the e1000 driver with 80 TX descriptors for the first adapter and

128 TX descriptors for the second adapter.

The default value for each parameter is generally the recommended setting,

unless otherwise noted.

        parameters, see the application note at:

        http://www.intel.com/design/network/applnots/ap450.htm

        A descriptor describes a data buffer and attributes related to

        the data buffer.  This information is accessed by the hardware.

AutoNeg

-------

(Supported only on adapters with copper connections)

NOTE:  Refer to the Speed and Duplex section of this readme for more

       information on the AutoNeg parameter.

Duplex

------

(Supported only on adapters with copper connections)

link partner is forced (either full or half), Duplex defaults to half-

duplex.

FlowControl

-----------

Valid Range:   0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx)

This parameter controls the automatic generation(Tx) and response(Rx)

to Ethernet PAUSE frames.

InterruptThrottleRate

---------------------

(not supported on Intel(R) 82542, 82543 or 82544-based adapters)

Valid Range:   0,1,3,100-100000 (0=off, 1=dynamic, 3=dynamic conservative)

Valid Range:   0,1,3,4,100-100000 (0=off, 1=dynamic, 3=dynamic conservative,

                                   4=simplified balancing)

Default Value: 3

The driver can limit the amount of interrupts per second that the adapter

the same as mode 3, the InterruptThrottleRate will be increased stepwise to

70000 for traffic in class "Lowest latency".

In simplified mode the interrupt rate is based on the ratio of Tx and

Rx traffic.  If the bytes per second rate is approximately equal, the

interrupt rate will drop as low as 2000 interrupts per second.  If the

traffic is mostly transmit or mostly receive, the interrupt rate could

be as high as 8000.

Setting InterruptThrottleRate to 0 turns off any interrupt moderation

and may improve small packet latency, but is generally not suitable

for bulk throughput traffic.

       be platform-specific.  If CPU utilization is not a concern, use

       RX_POLLING (NAPI) and default driver settings.

RxDescriptors

-------------

Valid Range:   80-256 for 82542 and 82543-based adapters

       for a higher number of receive descriptors may be denied.  In this

       case, use a lower number.

RxIntDelay

----------

Valid Range:   0-65535 (0=off)

          restoring the network connection.  To eliminate the potential

          for the hang ensure that RxIntDelay is set to 0.

RxAbsIntDelay

-------------

(This parameter is supported only on 82540, 82545 and later adapters.)

along with RxIntDelay, may improve traffic throughput in specific network

conditions.

Speed

-----

(This parameter is supported only on adapters with copper connections.)

partner is set to auto-negotiate, the board will auto-detect the correct

speed.  Duplex should also be set when Speed is set to either 10 or 100.

TxDescriptors

-------------

Valid Range:   80-256 for 82542 and 82543-based adapters

       higher number of transmit descriptors may be denied.  In this case,

       use a lower number.

TxDescriptorStep

----------------

Valid Range:    1 (use every Tx Descriptor)

		4 (use every 4th Tx Descriptor)

Default Value:  1 (use every Tx Descriptor)

On certain non-Intel architectures, it has been observed that intense TX

traffic bursts of short packets may result in an improper descriptor

writeback. If this occurs, the driver will report a "TX Timeout" and reset

the adapter, after which the transmit flow will restart, though data may

have stalled for as much as 10 seconds before it resumes.

The improper writeback does not occur on the first descriptor in a system

memory cache-line, which is typically 32 bytes, or 4 descriptors long.

Setting TxDescriptorStep to a value of 4 will ensure that all TX descriptors

are aligned to the start of a system memory cache line, and so this problem

will not occur.

NOTES: Setting TxDescriptorStep to 4 effectively reduces the number of

       TxDescriptors available for transmits to 1/4 of the normal allocation.

       This has a possible negative performance impact, which may be

       compensated for by allocating more descriptors using the TxDescriptors

       module parameter.

       There are other conditions which may result in "TX Timeout", which will

       not be resolved by the use of the TxDescriptorStep parameter. As the

       issue addressed by this parameter has never been observed on Intel

       Architecture platforms, it should not be used on Intel platforms.

TxIntDelay

----------

system is reporting dropped transmits, this value may be set too high

causing the driver to run out of available transmit descriptors.

TxAbsIntDelay

-------------

(This parameter is supported only on 82540, 82545 and later adapters.)

A value of '1' indicates that the driver should enable IP checksum

offload for received packets (both UDP and TCP) to the adapter hardware.

Copybreak

---------

Valid Range:   0-xxxxxxx (0=off)

Default Value: 256

Usage: insmod e1000.ko copybreak=128

Driver copies all packets below or equaling this size to a fresh Rx

buffer before handing it up the stack.

This parameter is different than other parameters, in that it is a

single (not 1,1,1 etc.) parameter applied to all driver instances and

it is also available during runtime at

/sys/module/e1000/parameters/copybreak

SmartPowerDownEnable

--------------------

Valid Range: 0-1

Default Value:  0 (disabled)

Allows PHY to turn off in lower power states. The user can turn off

this parameter in supported chipsets.

KumeranLockLoss

---------------

Valid Range: 0-1

Default Value: 1 (enabled)

This workaround skips resetting the PHY at shutdown for the initial

silicon releases of ICH8 systems.

Speed and Duplex Configuration

==============================

parameter should not be used.  Instead, use the Speed and Duplex parameters

previously mentioned to force the adapter to the same speed and duplex.

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(R) PRO/1000 Family of Adapters is e1000.

  As an example, if you install the e1000 driver for two PRO/1000 adapters

  (eth0 and eth1) and set the speed and duplex to 10full and 100half, add

  the following to modules.conf or or modprobe.conf:

       alias eth0 e1000

       alias eth1 e1000

       options e1000 Speed=10,100 Duplex=2,1

  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

  ------------

  Jumbo Frames support is enabled by changing the MTU to a value larger than

   setting in a different location.

  Notes:

  - To enable Jumbo Frames, increase the MTU size on the interface beyond

    1500.

  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.

  - The maximum MTU setting for Jumbo Frames is 16110.  This value coincides

    with the maximum Jumbo Frames size of 16128.

  - Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or

    loss of link.

  - Some Intel gigabit adapters that support Jumbo Frames have a frame size

    limit of 9238 bytes, with a corresponding MTU size limit of 9216 bytes.

    The adapters with this limitation are based on the Intel(R) 82571EB,

    82572EI, 82573L and 80003ES2LAN controller.  These correspond to the

    following product names:

     Intel(R) PRO/1000 PT Server Adapter

     Intel(R) PRO/1000 PT Desktop Adapter

     Intel(R) PRO/1000 PT Network Connection

     Intel(R) PRO/1000 PT Dual Port Server Adapter

     Intel(R) PRO/1000 PT Dual Port Network Connection

     Intel(R) PRO/1000 PF Server Adapter

     Intel(R) PRO/1000 PF Network Connection

     Intel(R) PRO/1000 PF Dual Port Server Adapter

     Intel(R) PRO/1000 PB Server Connection

     Intel(R) PRO/1000 PL Network Connection

     Intel(R) PRO/1000 EB Network Connection with I/O Acceleration

     Intel(R) PRO/1000 EB Backplane Connection with I/O Acceleration

     Intel(R) PRO/1000 PT Quad Port Server Adapter

  - Adapters based on the Intel(R) 82542 and 82573V/E controller do not

    support Jumbo Frames. These correspond to the following product names:

     Intel(R) PRO/1000 Gigabit Server Adapter

     Intel(R) PRO/1000 PM Network Connection

  - The following adapters do not support Jumbo Frames:

     Intel(R) 82562V 10/100 Network Connection

     Intel(R) 82566DM Gigabit Network Connection

     Intel(R) 82566DC Gigabit Network Connection

     Intel(R) 82566MM Gigabit Network Connection

     Intel(R) 82566MC Gigabit Network Connection

     Intel(R) 82562GT 10/100 Network Connection

     Intel(R) 82562G 10/100 Network Connection

  Ethtool

  -------

  The driver utilizes the ethtool interface for driver configuration and

  The latest release of ethtool can be found from

  http://sourceforge.net/projects/gkernel.

  NOTE: Ethtool 1.6 only supports a limited set of ethtool options.  Support

  for a more complete ethtool feature set can be enabled by upgrading

  ethtool to ethtool-1.8.1.

  Enabling Wake on LAN* (WoL)

  ---------------------------

  WoL is configured through the Ethtool* utility.  Ethtool is included with

  all versions of Red Hat after Red Hat 7.2.  For other Linux distributions,

  download and install Ethtool from the following website:

  http://sourceforge.net/projects/gkernel.

  For instructions on enabling WoL with Ethtool, refer to the website listed

  above.

  WoL is configured through the Ethtool* utility.

  WoL will be enabled on the system during the next shut down or reboot.

  For this driver version, in order to enable WoL, the e1000 driver must be

  loaded when shutting down or rebooting the system.

  Wake On LAN is only supported on port A for the following devices:

  Intel(R) PRO/1000 PT Dual Port Network Connection

  Intel(R) PRO/1000 PT Dual Port Server Connection

  Intel(R) PRO/1000 PT Dual Port Server Adapter

  Intel(R) PRO/1000 PF Dual Port Server Adapter

  Intel(R) PRO/1000 PT Quad Port Server Adapter

  NAPI

  ----

  NAPI (Rx polling mode) is enabled in the e1000 driver.

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

Known Issues

============

Dropped Receive Packets on Half-duplex 10/100 Networks

------------------------------------------------------

If you have an Intel PCI Express adapter running at 10mbps or 100mbps, half-

duplex, you may observe occasional dropped receive packets.  There are no

workarounds for this problem in this network configuration.  The network must

be updated to operate in full-duplex, and/or 1000mbps only.

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.

Jumbo Frames on Foundry BigIron 8000 switch

-------------------------------------------

There is a known issue using Jumbo frames when connected to a Foundry

BigIron 8000 switch.  This is a 3rd party limitation.  If you experience

loss of packets, lower the MTU size.

Allocating Rx Buffers when Using Jumbo Frames 

---------------------------------------------

Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if 

the available memory is heavily fragmented. This issue may be seen with PCI-X 

adapters or with packet split disabled. This can be reduced or eliminated 

by changing the amount of available memory for receive buffer allocation, by

increasing /proc/sys/vm/min_free_kbytes. 

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, either turn on ARP

filtering by entering:

    echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter

(this only works if your kernel's version is higher than 2.4.5),

NOTE: This setting is not saved across reboots.  The configuration

change can be made permanent by adding the line:

    net.ipv4.conf.all.arp_filter = 1

to the file /etc/sysctl.conf

      or,

install the interfaces in separate broadcast domains (either in

different switches or in a switch partitioned to VLANs).

82541/82547 can't link or are slow to link with some link partners

-----------------------------------------------------------------

There is a known compatibility issue with 82541/82547 and some

low-end switches where the link will not be established, or will

be slow to establish.  In particular, these switches are known to

be incompatible with 82541/82547:

    Planex FXG-08TE

    I-O Data ETG-SH8

To workaround this issue, the driver can be compiled with an override

of the PHY's master/slave setting.  Forcing master or forcing slave

mode will improve time-to-link.

    # make CFLAGS_EXTRA=-DE1000_MASTER_SLAVE=<n>

Where <n> is:

    0 = Hardware default

    1 = Master mode

    2 = Slave mode

    3 = Auto master/slave

Disable rx flow control with ethtool

------------------------------------

In order to disable receive flow control using ethtool, you must turn

off auto-negotiation on the same command line.

For example:

   ethtool -A eth? autoneg off rx off

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.

Support

=======