I40E(7D) Devices I40E(7D)

i40e —
Intel 710/722 Ethernet Device Driver

/dev/net/i40e*

The i40e driver is a GLDv3, multi-threaded, clonable, loadable device driver that supports the Data Link Provider Interface, dlpi(7P). The i40e driver supports the Intel 710 and 722 Ethernet Controller families of networking interface cards which come in 1 GbE, 10 GbE, 25 GbE, and 40 GbE variants.
In addition to basic device initialization and the sending and receiving of frames, it supports the following features:
At this time, the i40e driver does not enable the use of energy efficient Ethernet (EEE) or support the use of flow control through hardware pause frames.

For each device supported by the i40e installed in the system, a character-special file will be created. This file supports the Data Link Provider Interface (DLPI) which is documented in dlpi(7P). For most consumers, the use of libdlpi(3LIB), is recommended.
Each instance is assigned a unique ascending integer identifier. A device which has multiple ports may appear to the system as separate instances. The system does not provide a guarnatee on how these will be presented. Using this instance identifier, one can determine the exact character-special file to open. For example, the first instance enumerated in the system, with id 0, would be named i40e0. It exists in the file system at /dev/net/i40e0.

The i40e driver always performs auto-negotiation and depending on the model may negotiate to 40 Gbps, 25 Gbps, 10 Gbps, or 1 Gbps. At this time, the driver requires the use of auto-negotiation.
The i40e driver is managed by the dladm(1M) utility. dladm(1M) is the preferred interface for setting all properties. While driver.conf(4) based configuration is possible, dladm(1M) is recommended. The i40e driver may be joined into an aggregation based on the link aggregation control protocol (LACP) through dladm(1M).

The device supports the following properties which may be tuned through its driver.conf file, /kernel/drv/i40e.conf. Most of these properties cannot be changed after the device has been started. The device is started in response to a DLPI consumer opening the device and binding to it. This happens when an IP interfaces is plumbed or another dlpi(7P) consumer such as snoop(1M) or an LLDP daemon is started.
Some properties may be tuned at runtime with the dladm(1M) utility. Properties that can be will have the name of the dladm property called out explicitly.
These properties are not considered stable at this time. They may change and should not be relied on. They are considered Volatile. It is not expected that administrators of the system will have to tune these values.
default_mtu
Minimum: 1500 | Maximum: 9710 | Runtime Property: mtu
The default_mtu property determines the starting MTU of the various device instances. Note that the device's MTU also determines the upper bound of the MTU of all VNICs created over the device. The default MTU is 1500.
mr_enable
Minimum: 0 | Maximum: 1
The mr_enable proeprty determines whether or not support for multiple rings is enabled for the device. The default is always to enable them. It is not recommended to to disable them.
rx_ring_size
Minimum: 64 | Maximum: 4096
The rx_ring_size property determines the number of descriptors that will be used in each receive ring on the card. Administrators should not normally need to tune this value. Hardware requires that the ring size be a multiple of 32. The system will round up the set value to the nearest multiple of 32.
tx_ring_size
Minimum: 64 | Maximum: 4096
The tx_ring_size property determines the number of descriptors that will be used in each transmit ring on the card. Administrators should not normally need to tune this value. Hardware requires that the ring size be a multiple of 32. The system will round up the set value to the nearest multiple of 32.
tx_resched_threshold
Minimum: 8 | Maximum: Variable
The tx_resched_threshold property determines the number of descriptors that must be available for a frame to be transmitted. The maximum is variable. It is dependent on the value of the tx_ring_size property. At least eight descriptors must be available for the device to function correctly.
rx_limit_per_intr
Minimum: 16 | Maximum: 4096
The rx_limit_per_intr property determines the maximum number of packets that will be processed on a given ring during a single interrupt. This is done to try and guarantee some amount of liveness in the system. It is not expected that administrators will have to tune this value.
tx_hcksum_enable
Minimum: 0 | Maximum: 1
The tx_hcksum_enable property controls whether or not the device enables support for hardware checksuming of outgoing packets. The default is to always enable support for this. Turning it off will increase latency and decrease throughput when transmitting packets, but should be done if a hardware bug is suspected.
rx_hcksum_enable
Minimum: 0 | Maximum: 1
The rx_hcksum_enable property controls whether or not the device enables support for hardware checksuming of incoming packets. The default is to always enable support for this. Turning it off will increase latency and decrease throughput when receiving packets, but should be done if a hardware bug is suspected.
rx_dma_threshold
Minimum: 0 | Maximum: INT32_MAX | Runtime Property: _rx_dma_treshold
The rx_dma_treshold indicates the size in bytes of a received frame, including all of its headers, at which the driver should not copy the frame but instead bind DMA memory. By setting this property to its minimum, all frames will be processed with DMA binding. By setting this property to its maximum, all frames will be processed by copying the frame.
tx_lso_enable
Minimum: 0 | Maximum: 1
The tx_lso_enable property controls whether or not the device enables support for Large Segment Offloand (LSO) when transmitting packets. The default is to always enable support for this. Turning it off will decrease throughput when transmitting packets, but should be done if a hardware bug is suspected.

The i40e driver is only supported on x86 systems at this time.

 
 
/dev/net/i40e*
Per-instance character device.
 
 
/kernel/drv/i40e
32-bit device driver (x86).
 
 
/kernel/drv/amd64/i40e
64-bit device driver (x86).
 
 
/kernel/drv/i40e.conf
Driver configuration file.

dladm(1M), snoop(1M), driver.conf(4), dlpi(7P)
May 23, 2018 illumos