Documentation: e1000e: Prepare documentation for RST conversion

.. SPDX-License-Identifier: GPL-2.0+

Linux* Driver for Intel(R) Ethernet Network Connection

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

Intel Gigabit Linux driver.

Copyright(c) 1999 - 2013 Intel Corporation.

Copyright(c) 2008-2018 Intel Corporation.

Contents

========

- Additional Configurations

- Support

Identifying Your Adapter

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

For information on how to identify your adapter, and for the latest Intel

network drivers, refer to the Intel Support website:

https://www.intel.com/support

The e1000e driver supports all PCI Express Intel(R) Gigabit Network

Connections, except those that are 82575, 82576 and 82580-based*.

* NOTE: The Intel(R) PRO/1000 P Dual Port Server Adapter is supported by

  the e1000 driver, not the e1000e driver due to the 82546 part being used

  behind a PCI Express bridge.

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

Driver ID Guide at:

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

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:

    modprobe e1000e [<option>=<VAL1>,<VAL2>,...]

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

There needs to be a <VAL#> for each network port in the system supported by

this driver. The values will be applied to each instance, in function order.

For example::

Command Line Parameters

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

    modprobe e1000e InterruptThrottleRate=16000,16000

In this case, there are two network ports supported by e1000e in the system.

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

unless otherwise noted.

NOTES:  For more information about the InterruptThrottleRate,

        RxIntDelay, TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay

        parameters, see the application note at:

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

NOTE: A descriptor describes a data buffer and attributes related to the data

buffer. This information is accessed by the hardware.

InterruptThrottleRate

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

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

                                   4=simplified balancing)

Default Value: 3

:Valid Range: 0,1,3,4,100-100000

:Default Value: 3

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

will generate for incoming packets. It does this by writing a value to the

adapter that is based on the maximum amount of interrupts that the adapter

will generate per second.

Interrupt Throttle Rate controls the number of interrupts each interrupt

vector can generate per second. Increasing ITR lowers latency at the cost of

increased CPU utilization, though it may help throughput in some circumstances.

Setting InterruptThrottleRate to a value greater or equal to 100

will program the adapter to send out a maximum of that many interrupts

packets; and "Lowest latency", for almost completely small packets or

minimal traffic.

In dynamic conservative mode, the InterruptThrottleRate value is set to 4000

for traffic that falls in class "Bulk traffic". If traffic falls in the "Low

latency" or "Lowest latency" class, the InterruptThrottleRate is increased

stepwise to 20000. This default mode is suitable for most applications.

For situations where low latency is vital such as cluster or

grid computing, the algorithm can reduce latency even more when

InterruptThrottleRate is set to mode 1. In this mode, which operates

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

70000 for traffic in class "Lowest latency".

 - 0: Off

      Turns off any interrupt moderation and may improve small packet latency.

      However, this is generally not suitable for bulk throughput traffic due

      to the increased CPU utilization of the higher interrupt rate.

 - 1: Dynamic mode

      This mode attempts to moderate interrupts per vector while maintaining

      very low latency. This can sometimes cause extra CPU utilization. If

      planning on deploying e1000e in a latency sensitive environment, this

      parameter should be considered.

 - 3: Dynamic Conservative mode (default)

      In dynamic conservative mode, the InterruptThrottleRate value is set to

      4000 for traffic that falls in class "Bulk traffic". If traffic falls in

      the "Low latency" or "Lowest latency" class, the InterruptThrottleRate is

      increased stepwise to 20000. This default mode is suitable for most

      applications.

 - 4: Simplified Balancing mode

      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.

 - 100-100000:

      Setting InterruptThrottleRate to a value greater or equal to 100

      will program the adapter to send at most that many interrupts per second,

      even if more packets have come in. This reduces interrupt load on the

      system and can lower CPU utilization under heavy load, but will increase

      latency as packets are not processed as quickly.

NOTE: InterruptThrottleRate takes precedence over the TxAbsIntDelay and

       RxAbsIntDelay parameters.  In other words, minimizing the receive

       and/or transmit absolute delays does not force the controller to

       generate more interrupts than what the Interrupt Throttle Rate

       allows.

NOTE:  When e1000e is loaded with default settings and multiple adapters

       are in use simultaneously, the CPU utilization may increase non-

       linearly.  In order to limit the CPU utilization without impacting

       the overall throughput, we recommend that you load the driver as

       follows:

           modprobe e1000e InterruptThrottleRate=3000,3000,3000

       This sets the InterruptThrottleRate to 3000 interrupts/sec for

       the first, second, and third instances of the driver.  The range

       of 2000 to 3000 interrupts per second works on a majority of

       systems and is a good starting point, but the optimal value will

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

       RX_POLLING (NAPI) and default driver settings.

RxAbsIntDelay parameters. In other words, minimizing the receive and/or

transmit absolute delays does not force the controller to generate more

interrupts than what the Interrupt Throttle Rate allows.

RxIntDelay

----------

Valid Range:   0-65535 (0=off)

Default Value: 0

:Valid Range: 0-65535 (0=off)

:Default Value: 0

This value delays the generation of receive interrupts in units of 1.024

microseconds. Receive interrupt reduction can improve CPU efficiency if

properly tuned for specific network traffic.  Increasing this value adds

extra latency to frame reception and can end up decreasing the throughput

of TCP traffic.  If the system is reporting dropped receives, this value

may be set too high, causing the driver to run out of available receive

descriptors.

CAUTION:  When setting RxIntDelay to a value other than 0, adapters may

          hang (stop transmitting) under certain network conditions.  If

          this occurs a NETDEV WATCHDOG message is logged in the system

          event log.  In addition, the controller is automatically reset,

          restoring the network connection.  To eliminate the potential

          for the hang ensure that RxIntDelay is set to 0.

properly tuned for specific network traffic. Increasing this value adds extra

latency to frame reception and can end up decreasing the throughput of TCP

traffic. If the system is reporting dropped receives, this value may be set

too high, causing the driver to run out of available receive descriptors.

CAUTION: When setting RxIntDelay to a value other than 0, adapters may hang

(stop transmitting) under certain network conditions. If this occurs a NETDEV

WATCHDOG message is logged in the system event log. In addition, the

controller is automatically reset, restoring the network connection. To

eliminate the potential for the hang ensure that RxIntDelay is set to 0.

RxAbsIntDelay

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

Valid Range:   0-65535 (0=off)

Default Value: 8

:Valid Range: 0-65535 (0=off)

:Default Value: 8

This value, in units of 1.024 microseconds, limits the delay in which a

receive interrupt is generated.  Useful only if RxIntDelay is non-zero,

this value ensures that an interrupt is generated after the initial

packet is received within the set amount of time.  Proper tuning,

along with RxIntDelay, may improve traffic throughput in specific network

conditions.

receive interrupt is generated. This value ensures that an interrupt is

generated after the initial packet is received within the set amount of time,

which is useful only if RxIntDelay is non-zero. Proper tuning, along with

RxIntDelay, may improve traffic throughput in specific network conditions.

TxIntDelay

----------

Valid Range:   0-65535 (0=off)

Default Value: 8

:Valid Range: 0-65535 (0=off)

:Default Value: 8

This value delays the generation of transmit interrupts in units of

1.024 microseconds.  Transmit interrupt reduction can improve CPU

efficiency if properly tuned for specific network traffic.  If the

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

causing the driver to run out of available transmit descriptors.

This value delays the generation of transmit interrupts in units of 1.024

microseconds. Transmit interrupt reduction can improve CPU efficiency if

properly tuned for specific network traffic. If the system is reporting

dropped transmits, this value may be set too high causing the driver to run

out of available transmit descriptors.

TxAbsIntDelay

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

Valid Range:   0-65535 (0=off)

Default Value: 32

:Valid Range: 0-65535 (0=off)

:Default Value: 32

This value, in units of 1.024 microseconds, limits the delay in which a

transmit interrupt is generated.  Useful only if TxIntDelay is non-zero,

this value ensures that an interrupt is generated after the initial

packet is sent on the wire within the set amount of time.  Proper tuning,

along with TxIntDelay, may improve traffic throughput in specific

network conditions.

transmit interrupt is generated. It is useful only if TxIntDelay is non-zero.

It ensures that an interrupt is generated after the initial Packet is sent on

the wire within the set amount of time. Proper tuning, along with TxIntDelay,

may improve traffic throughput in specific network conditions.

Copybreak

copybreak

---------

Valid Range:   0-xxxxxxx (0=off)

Default Value: 256

:Valid Range: 0-xxxxxxx (0=off)

:Default Value: 256

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

The driver copies all packets below or equaling this size to a fresh receive

buffer before handing it up the stack.

This parameter differs from other parameters because 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/e1000e/parameters/copybreak.

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/e1000e/parameters/copybreak

To use copybreak, type::

    modprobe e1000e.ko copybreak=128

SmartPowerDownEnable

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

Valid Range: 0-1

Default Value:  0 (disabled)

:Valid Range: 0,1

:Default Value: 0 (disabled)

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

in supported chipsets.

Allows the 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)

:Valid Range: 0,1

:Default Value: 1 (enabled)

This workaround skips resetting the PHY at shutdown for the initial

silicon releases of ICH8 systems.

This workaround skips resetting the PHY at shutdown for the initial silicon

releases of ICH8 systems.

IntMode

-------

Valid Range: 0-2 (0=legacy, 1=MSI, 2=MSI-X)

Default Value: 2

:Valid Range: 0-2

:Default Value: 0

   +-------+----------------+

   | Value | Interrupt Mode |

   +=======+================+

   |   0   |     Legacy     |

   +-------+----------------+

   |   1   |       MSI      |

   +-------+----------------+

   |   2   |      MSI-X     |

   +-------+----------------+

IntMode allows 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.

This command will show different values for each type of interrupt::

Allows changing the interrupt mode at module load time, without requiring a

recompile. If the driver load fails to enable a specific interrupt mode, the

driver will try other interrupt modes, from least to most compatible.  The

interrupt order is MSI-X, MSI, Legacy.  If specifying MSI (IntMode=1)

interrupts, only MSI and Legacy will be attempted.

  cat /proc/interrupts

CrcStripping

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

Valid Range: 0-1

Default Value: 1 (enabled)

:Valid Range: 0,1

:Default Value: 1 (enabled)

Strip the CRC from received packets before sending up the network stack. If

you have a machine with a BMC enabled but cannot receive IPMI traffic after

WriteProtectNVM

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

Valid Range: 0,1

Default Value: 1

:Valid Range: 0,1

:Default Value: 1 (enabled)

If set to 1, configure the hardware to ignore all write/erase cycles to the

GbE region in the ICHx NVM (in order to prevent accidental corruption of the

NVM). This feature can be disabled by setting the parameter to 0 during initial

driver load.

NOTE: The machine must be power cycled (full off/on) when enabling NVM writes

via setting the parameter to zero. Once the NVM has been locked (via the

parameter at 1 when the driver loads) it cannot be unlocked except via power

cycle.

Additional Configurations

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

Debug

-----

:Valid Range: 0-16 (0=none,...,16=all)

:Default Value: 0

This parameter adjusts the level of debug messages displayed in the system logs.

Additional Features and Configurations

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

Jumbo Frames

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

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

  the default of 1500.  Use the ifconfig command to increase the MTU size.

  For example:

Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU)

to a value larger than the default value of 1500.

Use the ifconfig command to increase the MTU size. For example, enter the

following where <x> is the interface number::

    ifconfig eth<x> mtu 9000 up

  This setting is not saved across reboots.

Alternatively, you can use the ip command as follows::

  Notes:

    ip link set mtu 9000 dev eth<x>

    ip link set up dev eth<x>

  - The maximum MTU setting for Jumbo Frames is 9216.  This value coincides

    with the maximum Jumbo Frames size of 9234 bytes.

This setting is not saved across reboots. The setting change can be made

permanent by adding 'MTU=9000' to the file:

  - Using Jumbo frames at 10 or 100 Mbps is not supported and may result in

    poor performance or loss of link.

- For RHEL: /etc/sysconfig/network-scripts/ifcfg-eth<x>

- For SLES: /etc/sysconfig/network/<config_file>

NOTE: The maximum MTU setting for Jumbo Frames is 8996. This value coincides

with the maximum Jumbo Frames size of 9018 bytes.

  - Some adapters limit Jumbo Frames sized packets to a maximum of

    4096 bytes and some adapters do not support Jumbo Frames.

NOTE: Using Jumbo frames at 10 or 100 Mbps is not supported and may result in

poor performance or loss of link.

  - Jumbo Frames cannot be configured on an 82579-based Network device, if

NOTE: The following adapters limit Jumbo Frames sized packets to a maximum of

4088 bytes:

  - Intel(R) 82578DM Gigabit Network Connection

  - Intel(R) 82577LM Gigabit Network Connection

The following adapters do not support Jumbo Frames:

  - Intel(R) PRO/1000 Gigabit Server Adapter

  - Intel(R) PRO/1000 PM Network Connection

  - Intel(R) 82562G 10/100 Network Connection

  - Intel(R) 82562G-2 10/100 Network Connection

  - Intel(R) 82562GT 10/100 Network Connection

  - Intel(R) 82562GT-2 10/100 Network Connection

  - Intel(R) 82562V 10/100 Network Connection

  - Intel(R) 82562V-2 10/100 Network Connection

  - Intel(R) 82566DC Gigabit Network Connection

  - Intel(R) 82566DC-2 Gigabit Network Connection

  - Intel(R) 82566DM Gigabit Network Connection

  - Intel(R) 82566MC Gigabit Network Connection

  - Intel(R) 82566MM Gigabit Network Connection

  - Intel(R) 82567V-3 Gigabit Network Connection

  - Intel(R) 82577LC Gigabit Network Connection

  - Intel(R) 82578DC Gigabit Network Connection

NOTE: Jumbo Frames cannot be configured on an 82579-based Network device if

MACSec is enabled on the system.

ethtool

-------

The driver utilizes the ethtool interface for driver configuration and

  diagnostics, as well as displaying statistical information.  We

  strongly recommend downloading the latest version of ethtool at:

diagnostics, as well as displaying statistical information. The latest ethtool

version is required for this functionality. Download it at:

  https://kernel.org/pub/software/network/ethtool/

https://www.kernel.org/pub/software/network/ethtool/

  NOTE: When validating enable/disable tests on some parts (82578, for example)

  you need to add a few seconds between tests when working with ethtool.

NOTE: When validating enable/disable tests on some parts (for example, 82578),

it is necessary to add a few seconds between tests when working with ethtool.

Speed and Duplex Configuration

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

In addressing speed and duplex configuration issues, you need to distinguish

between copper-based adapters and fiber-based adapters.

In the default mode, an Intel(R) Ethernet Network Adapter using copper

connections will attempt to auto-negotiate with its link partner to determine

the best setting. If the adapter cannot establish link with the link partner

using auto-negotiation, you may need to manually configure the adapter and link

partner to identical settings to establish link and pass packets. This should

only be needed when attempting to link with an older switch that does not

support auto-negotiation or one that has been forced to a specific speed or

duplex mode. Your link partner must match the setting you choose. 1 Gbps speeds

and higher cannot be forced. Use the autonegotiation advertising setting to

manually set devices for 1 Gbps and higher.

Speed, duplex, and autonegotiation advertising are configured through the

ethtool* utility.

Caution: Only experienced network administrators should force speed and duplex

or change autonegotiation advertising manually. The settings at the switch must

always match the adapter settings. Adapter performance may suffer or your

adapter may not operate if you configure the adapter differently from your

switch.

An Intel(R) Ethernet Network Adapter using fiber-based connections, however,

will not attempt to auto-negotiate with its link partner since those adapters

operate only in full duplex and only at their native speed.

  Speed and Duplex

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

  Speed and Duplex are configured through the ethtool* utility. For

  instructions,  refer to the ethtool man page.

Enabling Wake on LAN* (WoL)

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

  WoL is configured through the ethtool* utility. For instructions on

  enabling WoL with ethtool, refer to the ethtool man page.

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 e1000e driver must be

  loaded when shutting down or rebooting the system.

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

this driver version, in order to enable WoL, the e1000e driver must be loaded

prior to shutting down or suspending the system.

NOTE: 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

- Intel(R) Gigabit PT Quad Port Server ExpressModule

  In most cases Wake On LAN is only supported on port A for multiple port

  adapters. To verify if a port supports Wake on Lan run ethtool eth<X>.

Support

=======

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

    www.intel.com/support/

https://www.intel.com/support/

or the Intel Wired Networking project hosted by Sourceforge at:

    http://sourceforge.net/projects/e1000

https://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

If an issue is identified with the released source code on a supported kernel

with a supported adapter, email the specific information related to the issue

to e1000-devel@lists.sf.net.