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

  Intel Gigabit Linux driver.
  Copyright(c) 1999 - 2010 Intel Corporation.

  
  Contents
  ========

  - Identifying Your Adapter
  - Command Line Parameters
  - Speed and Duplex Configuration
  - Additional Configurations

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

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

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

  unless otherwise noted.
  
  NOTES:  For more information about the AutoNeg, Duplex, and Speed
          parameters, see the "Speed and Duplex Configuration" section in
          this document.

          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

  AutoNeg
  -------
  (Supported only on adapters with copper connections)
  Valid Range:   0x01-0x0F, 0x20-0x2F

  Default Value: 0x2F

  This parameter is a bit-mask that specifies the speed and duplex settings
  advertised by the adapter.  When this parameter is used, the Speed and
  Duplex parameters must not be specified.

  
  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)
  Valid Range:   0-2 (0=auto-negotiate, 1=half, 2=full)

  Default Value: 0

  This defines the direction in which data is allowed to flow.  Can be
  either one or two-directional.  If both Duplex and the link partner are
  set to auto-negotiate, the board auto-detects the correct duplex.  If the
  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)
  Default Value: Reads flow control settings from the EEPROM
  
  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:   0,1,3,4,100-100000 (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

  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.
  
  Setting InterruptThrottleRate to a value greater or equal to 100
  will program the adapter to send out a maximum of 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.

  The default behaviour of the driver previously assumed a static
  InterruptThrottleRate value of 8000, providing a good fallback value for
  all traffic types,but lacking in small packet performance and latency.
  The hardware can handle many more small packets per second however, and

  for this reason an adaptive interrupt moderation algorithm was implemented.
  
  Since 7.3.x, the driver has two adaptive modes (setting 1 or 3) in which

  it dynamically adjusts the InterruptThrottleRate value based on the traffic

  that it receives. After determining the type of incoming traffic in the last

  timeframe, it will adjust the InterruptThrottleRate to an appropriate value

  for that traffic.
  
  The algorithm classifies the incoming traffic every interval into

  classes.  Once the class is determined, the InterruptThrottleRate value is
  adjusted to suit that traffic type the best. There are three classes defined:

  "Bulk traffic", for large amounts of packets of normal size; "Low latency",
  for small amounts of traffic and/or a significant percentage of small

  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".

  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.

  
  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.

  CAUTION:  If you are using the Intel(R) PRO/1000 CT Network Connection

            (controller 82547), setting InterruptThrottleRate to a value
            greater than 75,000, may hang (stop transmitting) adapters

            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 InterruptThrottleRate is set no greater
            than 75,000 and is not set to 0.
  
  NOTE:  When e1000 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 e1000 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.

  RxDescriptors

  -------------
  Valid Range:   80-256 for 82542 and 82543-based adapters
                 80-4096 for all other supported adapters

  Default Value: 256

  This value specifies the number of receive buffer descriptors allocated
  by the driver.  Increasing this value allows the driver to buffer more
  incoming packets, at the expense of increased system memory utilization.
  
  Each descriptor is 16 bytes.  A receive buffer is also allocated for each

  descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending

  on the MTU setting. The maximum MTU size is 16110.

  NOTE:  MTU designates the frame size.  It only needs to be set for Jumbo
         Frames.  Depending on the available system resources, the request
         for a higher number of receive descriptors may be denied.  In this

         case, use a lower number.

  RxIntDelay

  ----------
  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.

  RxAbsIntDelay
  -------------
  (This parameter is supported only on 82540, 82545 and later adapters.)
  Valid Range:   0-65535 (0=off)

  Default Value: 128

  
  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.

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

  Valid Settings: 0, 10, 100, 1000

  Default Value:  0 (auto-negotiate at all supported speeds)
  
  Speed forces the line speed to the specified value in megabits per second

  (Mbps).  If this parameter is not specified or is set to 0 and the link

  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
                 80-4096 for all other supported adapters

  Default Value: 256

  This value is the number of transmit descriptors allocated by the driver.

  Increasing this value allows the driver to queue more transmits.  Each

  descriptor is 16 bytes.
  
  NOTE:  Depending on the available system resources, the request for a
         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

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

  Default Value: 64

  
  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
  -------------
  (This parameter is supported only on 82540, 82545 and later adapters.)
  Valid Range:   0-65535 (0=off)

  Default Value: 64

  
  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.
  
  XsumRX
  ------
  (This parameter is NOT supported on the 82542-based adapter.)
  Valid Range:   0-1

  Default Value: 1

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

  Three keywords are used to control the speed and duplex configuration.
  These keywords are Speed, Duplex, and AutoNeg.

  If the board uses a fiber interface, these keywords are ignored, and the

  fiber interface board only links at 1000 Mbps full-duplex.
  
  For copper-based boards, the keywords interact as follows:

    The default operation is auto-negotiate.  The board advertises all

    supported speed and duplex combinations, and it links at the highest
    common speed and duplex mode IF the link partner is set to auto-negotiate.

    If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps
    is advertised (The 1000BaseT spec requires auto-negotiation.)

    If Speed = 10 or 100, then both Speed and Duplex should be set.  Auto-
    negotiation is disabled, and the AutoNeg parameter is ignored.  Partner

    SHOULD also be forced.
  
  The AutoNeg parameter is used when more control is required over the
  auto-negotiation process.  It should be used when you wish to control which
  speed and duplex combinations are advertised during the auto-negotiation
  process.

  The parameter may be specified as either a decimal or hexadecimal value as

  determined by the bitmap below.

  Bit position   7      6      5       4       3      2      1       0
  Decimal Value  128    64     32      16      8      4      2       1
  Hex value      80     40     20      10      8      4      2       1
  Speed (Mbps)   N/A    N/A    1000    N/A     100    100    10      10
  Duplex                       Full            Full   Half   Full    Half

  Some examples of using AutoNeg:

    modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half)
    modprobe e1000 AutoNeg=1 (Same as above)
    modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full)
    modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full)
    modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half)
    modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100
    Half)
    modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full)
    modprobe e1000 AutoNeg=32 (Same as above)

  Note that when this parameter is used, Speed and Duplex must not be specified.
  
  If the link partner is forced to a specific speed and duplex, then this
  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
  =========================

    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:

  
         ifconfig eth<x> mtu 9000 up
  
    This setting is not saved across reboots.  It can be made permanent if
    you add:
  
         MTU=9000

     to the file /etc/sysconfig/network-scripts/ifcfg-eth<x>.  This example
     applies to the Red Hat distributions; other distributions may store this
     setting in a different location.

    Notes:

    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.

    - 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

    Ethtool
    -------

    The driver utilizes the ethtool interface for driver configuration and

    diagnostics, as well as displaying statistical information.  The ethtool

    version 1.6 or later is required for this functionality.
  
    The latest release of ethtool can be found from

    http://ftp.kernel.org/pub/software/network/ethtool/

    Enabling Wake on LAN* (WoL)
    ---------------------------

    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.

  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