IX(4)

NAME
ix - Intel(R) 10Gb Ethernet driver

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

device ix

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

    if_ix_load="YES"

DESCRIPTION
The ix driver provides support for PCI Express 10Gb Ethernet adapters based on the Intel 82598, 82599, and X540 Ethernet controller chips. The ix 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 ix 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. And if both TSO and multiple tranmission queues are used, the round-robin arbitration between transmission queues is done at the TCP segment boundary after the hardware segmentation is performed.

82598 supports 16 reception queues and 32 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.

82599 and X540 supports 16 reception queues and 64 transmission queues. MSI-X is enable by default. However, due to the number of MSI-X vectors is 64, at most 16 reception queues and 32 transmission queues will be enabled under MSI-X mode.

The ix driver supports the following media types:

autoselect
    Enables auto-negotiation for speed and duplex.

The ix driver supports the following media options:

rxpause
    Enable flow control PAUSE reception.

txpause
    Enable flow control PAUSE transmission.

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

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

HARDWARE
The ix driver supports Gigabit Ethernet adapters based on the Intel 82598, 82599, and X540 controller chips:

•   Intel 10 Gigabit AT Server Adapter
•   Intel 82598EB 10 Gigabit Ethernet Controller
•   Intel 82599EB 10 Gigabit Ethernet Controller
•   Intel 82599EN 10 Gigabit Ethernet Controller
•   Intel 82599ES 10 Gigabit Ethernet Controller
•   Intel Ethernet Controller X540-AT2
•   Intel Ethernet Controller X550-AT
•   Intel Ethernet Controller X550-AT2
•   Intel Ethernet Controller X550-BT2
•   Intel Ethernet Connection X557-AT
•   Intel Ethernet Connection X557-AT2
•   Intel Ethernet Connection X557-AT4
•   Intel Ethernet Controller X710-AM2
•   Intel Ethernet Converged Network Adapter X520-DA1
•   Intel Ethernet Converged Network Adapter X520-DA2
•   Intel Ethernet Converged Network Adapter X520-LR1
•   Intel Ethernet Converged Network Adapter X520-QDA1
•   Intel Ethernet Converged Network Adapter X520-SR1
•   Intel Ethernet Converged Network Adapter X520-SR2
•   Intel Ethernet Converged Network Adapter X540-T1
•   Intel Ethernet Converged Network Adapter X540-T2
•   Intel Ethernet Converged Network Adapter X550-T1
•   Intel Ethernet Converged Network Adapter X550-T2
•   Intel Ethernet Converged Network Adapter X710-DA2
•   Intel Ethernet Converged Network Adapter X710-DA4

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

hw.ix.rxd hw.ixY.rxd
    Number of receive descriptors allocated by the driver. The default value is 2048. The minimum is 64, and the maximum is 4096.

hw.ix.txd hw.ixY.txd
    Number of transmit descriptors allocated by the driver. The default value is 2048. The minimum is 64, and the maximum is 4096.

hw.ix.rxr hw.ixY.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.ix.txr hw.ixY.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.ix.msix.enable hw.ixY.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.ix.msi.enable hw.ixY.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.ixY.msi.cpu
    If MSI is used, it specifies the MSI's target CPU.

hw.ix.unsupported_sfp
    By default, this driver does not allow "unsupported" SFP modules. This behavior can be changed by setting this tunable to 1.

hw.ix.flow_ctrl hw.ixY.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.

hw.ix.direct_input
    By default, if the polling(4) is enabled, the driver will handle input packets directly, instead of queuing input packets for further processing. The direct input packets handling improves performance and stablize latency.

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

rxr Number of reception queues could be enabled (read-only). Use the tunable hw.ix.rxr or hw.ixY.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.ix.txr or hw.ixY.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.ix.rxd or hw.ixY.rxd to configure it.

txd Number of descriptors per transmission queue (read-only). Use the tunable hw.ix.txd or hw.ixY.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 8000 by default (125us).

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 8000 by default (125us).

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 6000 by default (~150us).

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 8000 by default (125us).

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.

direct_input
    See hw.ix.direct_input. polling(4) needs to be turned off and turned on again to make this variable take effect.

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

HISTORY
The ix device driver first appeared in DragonFly 3.1.

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