IGB(4)

NAME
igb - Intel(R) PRO/1000 PCI Express Gigabit Ethernet adapter driver

SYNOPSIS
To compile this driver into the kernel, place the following line in your kernel configuration file:

device ig_hal
device igb

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

    ig_hal_load="YES"
    if_igb_load="YES"

DESCRIPTION
The igb driver provides support for PCI Express Gigabit Ethernet adapters based on the Intel 82575, 82576, 82580, I210, I211, I350 and I354 Ethernet controller chips. The igb driver supports:

•   Transmit/Receive checksum offload for IP/UDP/TCP
•   Interrupt moderation
•   TCP segmentation offload (TSO)
•   Receive side scaling (RSS)
•   Multiple tranmission queues
•   Multiple vector MSI-X
•   VLAN tag stripping and inserting

If polling(4) or MSI-X is used, by default, the igb driver will try enabling as many reception queues and transmission queues as are allowed by the number of CPUs in the system.

If multiple transmission queues are used, the round-robin arbitration is performed among the transmission queues. It should be noted that if both TSO and multiple transmission queues are used, for 82575, the round-robin arbitration between transmission queues is done at the TSO packet boundary; for the reset of the hardware, the round-robin arbitration between transmission queues is done at the TCP segment boundary after the hardware segmentation is performed.

82575 supports 4 reception queues and 4 transmission queues. MSI-X is not enabled due to hardware errata. Under MSI or legacy interrupt mode, 2 reception queues are enabled for hardware RSS hash and only 1 transmission queue is enable.

82576 supports 16 reception queues and 16 transmission queues. MSI-X is enable by default. However, due to the number of MSI-X vectors is 10, at most 8 reception queues and 8 transmission queues will be enabled under MSI-X mode. When polling(4) is enabled on the devices, at most 16 reception queues and 16 transmission queues will be enabled.

82580, I350 and I354 support 8 reception queues and 8 transmission queues. MSI-X is enabled by default.

I210 supports 4 reception queues and 4 transmission queues. MSI-X is enabled by default.

I211 supports 2 reception queues and 2 transmission queues. MSI-X is enabled by default.

The igb driver supports the following media types:

autoselect
    Enables auto-negotiation for speed and duplex.

10baseT/UTP
    Sets 10Mbps operation. Use the mediaopt option to select full-duplex mode.

100baseTX
    Sets 100Mbps operation. Use the mediaopt option to select full-duplex mode.

1000baseSX
    Sets 1000Mbps operation. Only full-duplex mode is supported at this speed.

1000baseT
    Sets 1000Mbps operation. Only full-duplex mode is supported at this speed.

The igb driver supports the following media options:

full-duplex
    Forces full-duplex operation

half-duplex
    Forces half-duplex operation.

rxpause
    Enable flow control PAUSE reception. This is only supported by autoselect and full-duplex mode.

txpause
    Enable flow control PAUSE transmission. This is only supported by autoselect and full-duplex mode.

forcepause
    Force flow control PAUSE operation as configured by rxpause and txpause media options.

Only use mediaopt to set the driver to full-duplex. If mediaopt is not specified, the driver defaults to half-duplex.

For more information on configuring this device, see ifconfig(8). The igb driver supports polling(4).

HARDWARE
The igb driver supports Gigabit Ethernet adapters based on the Intel 82575, 82576, 82580, I210, I211, I350 and I354 controller chips:

•   Intel 82575EB Gigabit Ethernet Controller
•   Intel 82576EB Gigabit Ethernet Controller
•   Intel 82576NS Gigabit Ethernet Controller
•   Intel 82580EB Gigabit Ethernet Controller
•   Intel Ethernet Controller I350-AM2
•   Intel Ethernet Controller I350-AM4
•   Intel Ethernet Controller I350-BT2
•   Intel Ethernet Controller I210-AS
•   Intel Ethernet Controller I210-AT
•   Intel Ethernet Controller I210-CS
•   Intel Ethernet Controller I210-IS
•   Intel Ethernet Controller I210-IT
•   Intel Ethernet Controller I211-AT
•   Intel Ethernet Server Adapter I210-T1
•   Intel Ethernet Server Adapter I340-F4
•   Intel Ethernet Server Adapter I340-T4
•   Intel Ethernet Server Adapter I350-F2
•   Intel Ethernet Server Adapter I350-F4
•   Intel Ethernet Server Adapter I350-T2
•   Intel Ethernet Server Adapter I350-T4
•   Intel Gigabit EF Dual Port Server Adapter
•   Intel Gigabit ET Dual Port Server Adapter
•   Intel Gigabit ET Quad Port Server Adapter
•   Intel Gigabit ET2 Quad Port Server Adapter
•   Intel Gigabit VT Quad Port Server Adapter

TUNABLES
Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5). X is the device unit number.

hw.igb.rxd hw.igbX.rxd
    Number of receive descriptors allocated by the driver. The default value is 512. The minimum is 256, and the maximum is 4096.

hw.igb.txd hw.igbX.txd
    Number of transmit descriptors allocated by the driver. The default value is 1024. The minimum is 256, and the maximum is 4096.

hw.igb.rxr hw.igbX.rxr
    This tunable specifies the number of reception queues could be enabled. Maximum allowed value for these tunables is device specific and it must be power of 2 aligned. Setting these tunables to 0 allows the driver to make as many reception queues ready-for-use as allowed by the number of CPUs.

hw.igb.txr hw.igbX.txr
    This tunable specifies the number of transmission queues could be enabled. Maximum allowed value for these tunables is device specific and it must be power of 2 aligned. Setting these tunables to 0 allows the driver to make as many transmission queues ready-for-use as allowed by the number of CPUs.

hw.igb.msix.enable hw.igbX.msix.enable
    By default, the driver will use MSI-X if it is supported. This behaviour can be turned off by setting this tunable to 0.

hw.igb.msi.enable hw.igbX.msi.enable
    If MSI-X is disabled and MSI is supported, the driver will use MSI. This behavior can be turned off by setting this tunable to 0.

hw.igbX.msi.cpu
    If MSI is used, it specifies the MSI's target CPU.

hw.igbX.irq.unshared
    If legacy interrupt is used, by default, the driver assumes the interrupt could be shared. Setting this tunable to 1 allows the driver to perform certain optimization based on the knowledge that the interrupt is not shared.

hw.igb.flow_ctrl hw.igbX.flow_ctrl
    The default flow control settings. Supported values are: rxpause (only enable PAUSE reception), txpause (only enable PAUSE transmission), full (enable PAUSE reception and transmission), none (disable flow control PAUSE operation), force-rxpause (force PAUSE reception), force-txpause (force PAUSE transmission), force-full (forcefully enable PAUSE reception and transmission), force-none (forcefully disable flow control PAUSE operation). Default is none.

MIB Variables
A number of per-interface variables are implemented in the dev.igb.X branch of the sysctl(3) MIB.

rxr Number of reception queues could be enabled (read-only). Use the tunable hw.igb.rxr or hw.igbX.rxr to configure it.

rxr_inuse
    Number of reception queues being used (read-only).

txr Number of transmission queues could be enabled (read-only). Use the tunable hw.igb.txr or hw.igbX.txr to configure it.

txr_inuse
    Number of transmission queues being used (read-only).

rxd Number of descriptors per reception queue (read-only). Use the tunable hw.igb.rxd or hw.igbX.rxd to configure it.

txd Number of descriptors per transmission queue (read-only). Use the tunable hw.igb.txd or hw.igbX.txd to configure it.

rxtx_intr_rate
    If MSI or legacy interrupt is used, this sysctl controls the highest possible frequency that interrupt could be generated by the device. If MSI-X is used, this sysctl controls the highest possible frequency that interrupt could be generated by the MSI-X vectors, which aggregate transmission queue and reception queue procecssing. It is 6000 by default (~150us).

rx_intr_rate
    If MSI-X is used, this sysctl controls the highest possible frequency that interrupt could be generated by the MSI-X vectors, which only process reception queue. It is 6000 by default (~150us).

tx_intr_rate
    If MSI-X is used, this sysctl controls the highest possible frequency that interrupt could be generated by the MSI-X vectors, which only process transmission queue. It is 4000 by default (250us).

sts_intr_rate
    If MSI-X is used, this sysctl controls the highest possible frequency that interrupt could be generated by the MSI-X vectors, which only process chip status changes. It is 6000 by default (~150us).

tx_intr_nsegs
    Transmission interrupt is asked to be generated upon every tx_intr_nsegs transmission descritors having been setup. The default value is 1/16 of the number of transmission descriptors per queue.

tx_wreg_nsegs
    The number of transmission descriptors should be setup before the hardware register is written. Setting this value too high will have negative effect on transmission timeliness. Setting this value too low will hurt overall transmission performance due to the frequent hardware register writing. The default value is 8.

rx_wreg_nsegs
    The number of reception descriptors should be setup before the hardware register is written. Setting this value too high will make device drop incoming packets. Setting this value too low will hurt overall reception performance due to the frequent hardware register writing. The default value is 32.

SEE ALSO
altq(4), arp(4), ifmedia(4), netintro(4), ng_ether(4), polling(4), vlan(4), ifconfig(8)

HISTORY
The igb device driver first appeared in FreeBSD 7.1.

AUTHORS
The igb driver was written by Intel Corporation <freebsdnic@mailbox.intel.com>.