IXV(4)

NAME
ixv - ixv -- Intel(R) Ethernet VF Driver for the FreeBSD* operating system

  Contents

•   ixv FreeBSD* VF Driver for Intel(R) Ethernet 10 Gigabit PCI Express Server Adapters

•   Overview

•   Related Documentation

•   Identifying Your Adapter

•   The VF Driver

•   Building and Installation

•   Configuration and Tuning

•   Known Issues/Troubleshooting

•   Support

•   Trademarks

OVERVIEW

This README describes the FreeBSD* Virtual Function (VF) driver for Intel(R) Ethernet, ixv. This driver has been developed for use with all community-supported versions of FreeBSD.

For questions related to hardware requirements, refer to the documentation supplied with your Intel Ethernet Adapter. All hardware requirements listed apply to use with FreeBSD.

NOTE: Devices based on the Intel(R) Ethernet Controller X552 and Intel(R) Ethernet Controller X553 do not support the following features:

•   Low Latency Interrupts (LLI)

    The associated Physical Function (PF) driver for this driver is ix.

RELATED DOCUMENTATION

See the "Intel(R) Ethernet Adapters and Devices User Guide" for additional information on features. It is available on the Intel website at either of the following:

•   https://cdrdv2.intel.com/v1/dl/getContent/705831

•   https://www.intel.com/content/www/us/en/download/19373/adapter-user-guide-for-intel-ethernet-adapters.html

IDENTIFYING YOUR ADAPTER

The driver is compatible with devices based on the following:

•   Intel(R) Ethernet Controller 82598

•   Intel(R) Ethernet Controller 82599

•   Intel(R) Ethernet Controller X520

•   Intel(R) Ethernet Controller X540

•   Intel(R) Ethernet Controller x550

•   Intel(R) Ethernet Controller X552

•   Intel(R) Ethernet Controller X553

•   Intel(R) Ethernet Controller E610

    For information on how to identify your adapter, and for the latest Intel network drivers, refer to the Intel Support website at http://www.intel.com/support.

THE VF DRIVER

In the FreeBSD guest, the ixv driver would be loaded and will function using the VF device assigned to it.

The VF driver provides most of the same functionality as the core driver, but is actually a subordinate to the host. Access to many controls is accomplished by a request to the host via what is called the "Admin queue." These are startup and initialization events, however; once in operation, the device is self-contained and should achieve near native performance.

Some notable limitations of the VF environment:

•   For security reasons, the driver is never permitted to be promiscuous, therefore a tcpdump will not behave the same with the interface.

•   Media info is not available from the PF, so it will always appear as auto.

BUILDING AND INSTALLATION

NOTE: This driver package is to be used only as a standalone archive and the user should not attempt to incorporate it into the kernel source tree.

In the instructions below, x.x.x is the driver version as indicated in the name of the driver tar file.

1.  Move the driver tar file to the directory of your choice. For example, use /home/username/ixv or /usr/local/src/ixv.

2.  Untar/unzip the archive:

        tar xzf ixv-x.x.x.tar.gz

    This will create the ixv-x.x.x directory.

3.  To install the man page:

        cd ixv-x.x.x
        gzip -c ixv.4 > /usr/share/man/man4/ixv.4.gz

4.  To load the driver onto a running system:

        cd ixv-x.x.x/src
        make
        kldload ./if_ixv.ko

5.  To assign an IP address to the interface, enter the following, where X is the interface number for the device:

        ifconfig ixvX <IP_address>

6.  Verify that the interface works. Enter the following, where <IP_address> is the IP address for another machine on the same subnet as the interface that is being tested:

        ping <IP_address>

7.  If you want the driver to load automatically when the system is booted:

        cd ixv-x.x.x/src
        make
        make install

    Then edit /boot/loader.conf, and add the following line:

        if_ixv_load="YES"

8.  If you want the device to connect to a network without manual intervention after a boot, edit /etc/rc.conf and create the appropriate ifconfig_<driver>X entry:

        ifconfig_ixvX="<ifconfig_settings>"

    Example usage:

        ifconfig_ixv0="inet 192.168.10.1 netmask 255.255.255.0"

    NOTE: For assistance, see the ifconfig man page.

CONFIGURATION AND TUNING

  Important System Configuration Changes

•   Change the file /etc/sysctl.conf, and add the line:

        hw.intr_storm_threshold: 0

    The default is 1000.

•   Best throughput results are seen with a large MTU; use 9710 if possible. The default number of descriptors per ring is 1024. Increasing this may improve performance, depending on your use case.

•   If you have a choice, run on a 64-bit OS rather than a 32-bit OS.

  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.

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.

By default, the adapter auto-negotiates the speed and duplex of the connection. If there is a specific need, the ifconfig utility can be used to configure the speed and duplex settings on the adapter.

NOTE: For the Intel(R) Ethernet Connection X552 10 GbE SFP+, you must specify the desired speed.

Example usage:

    ifconfig ixvX <IP_address> media 100baseTX mediaopt full-duplex

NOTE: Only use mediaopt to set the driver to full-duplex. If mediaopt is not specified and you are not running at gigabit speed, the driver defaults to half-duplex.

If the interface is currently forced to 100 full duplex, you must use this command to change to half duplex:

    ifconfig ixvX <IP_address> media 100baseTX -mediaopt full-duplex

This driver supports the following media type options:

autoselect
    Enables auto-negotiation for speed and duplex.

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

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

1000baseTX
    Sets speed to 1000 Mbps. In this case, the driver supports only full-duplex mode.

1000baseSX
    Sets speed to 1000 Mbps. In this case, the driver supports only full-duplex mode.

    For more information on the ifconfig utility, refer to the ifconfig man page.

  Jumbo Frames

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 ixvX mtu 9000

To confirm an interface's MTU value, use the ifconfig command.

To confirm the MTU used between two specific devices, use:

    route get <destination_IP_address>

NOTE:

•   The maximum MTU setting for jumbo frames is 9710. This corresponds to the maximum jumbo frame size of 9728 bytes.

•   This driver will attempt to use multiple page sized buffers to receive each jumbo packet. This should help to avoid buffer starvation issues when allocating receive packets.

•   Packet loss may have a greater impact on throughput when you use jumbo frames. If you observe a drop in performance after enabling jumbo frames, enabling flow control may mitigate the issue.

•   For 82599-based network connections, if you are enabling jumbo frames in a virtual function (VF), jumbo frames must first be enabled in the physical function (PF). The VF MTU setting cannot be larger than the PF MTU.

  VLANS

To create a new VLAN interface:

    ifconfig <vlan_name> create

To associate the VLAN interface with a physical interface and assign a VLAN ID, IP address, and netmask:

    ifconfig <vlan_name> <ip_address> netmask <subnet_mask> vlan <vlan_id>
    vlandev <physical_interface>

Example:

    ifconfig vlan10 10.0.0.1 netmask 255.255.255.0 vlan 10 vlandev ixv0

In this example, all packets will be marked on egress with 802.1Q VLAN tags, specifying a VLAN ID of 10.

To remove a VLAN interface:

    ifconfig <vlan_name> destroy

  Checksum Offload

Checksum offloading supports both TCP and UDP packets and is supported for both transmit and receive.

Checksum offloading can be enabled or disabled using ifconfig. Both transmit and receive offloading will be either enabled or disabled together. You cannot enable/disable one without the other.

To enable checksum offloading:

    ifconfig ixvX rxcsum

To disable checksum offloading:

    ifconfig ixvX -rxcsum

To confirm the current setting:

    ifconfig ixvX

Look for the presence or absence of the following line:

    options=3 <RXCSUM,TXCSUM>

See the ifconfig man page for further information.

  TSO

TSO (TCP Segmentation Offload) supports both IPv4 and IPv6. TSO can be disabled and enabled using the ifconfig utility or sysctl.

NOTE: TSO requires Tx checksum, if Tx checksum is disabled, TSO will also be disabled.

To enable/disable TSO in the stack:

    sysctl net.inet.tcp.tso=0 (or 1 to enable it)

Doing this disables/enables TSO in the stack and affects all installed adapters.

To disable BOTH TSO IPv4 and IPv6, where X is the number of the interface in use:

    ifconfig ixvX -tso

To enable BOTH TSO IPv4 and IPv6:

    ifconfig ixvX tso

You can also enable/disable IPv4 TSO or IPv6 TSO individually. Simply replace tso or -tso in the above command with tso4 or tso6. For example, to disable TSO IPv4:

    ifconfig ixvX -tso4

To disable TSO IPv6:

    ifconfig ixvX -tso6

  LRO

LRO (Large Receive Offload) may provide Rx performance improvement. However, it is incompatible with packet-forwarding workloads. You should carefully evaluate the environment and enable LRO when possible.

To enable:

    ifconfig ixvX lro

It can be disabled by using:

    ifconfig ixvX -lro

  Link-Level Flow Control (LFC)

Ethernet Flow Control (IEEE 802.3x) can be configured with sysctl to enable receiving and transmitting pause frames for ixv. When transmit is enabled, pause frames are generated when the receive packet buffer crosses a predefined threshold. When receive is enabled, the transmit unit will halt for the time delay specified when a pause frame is received.

NOTE: You must have a flow control capable link partner.

Flow Control is enabled by default.

The ixv driver also supports a hw.ixv.flow_control load-time parameter to set the initial flow control configuration on all supported interfaces in a system. You can set the tunable using the kenv command and then reload the driver, or by adding a line to /boot/loader.conf and rebooting the system.

Use sysctl to change the flow control settings for a single interface without reloading the driver.

The available values for flow control are:

•   0 = Disable flow control

•   1 = Enable Rx pause

•   2 = Enable Tx pause

•   3 = Enable Rx and Tx pause

    Examples:

•   To set the tunable in the config file, add the following line to /boot/loader.conf and then reboot the system:

        hw.ixv.flow_control=3

•   To set the tunable using kenv, use the following command and then reload the driver:

        kenv hw.ixv.flow_control=3

•   To remove the tunable and return the system to its default settings:

        kenv -u hw.ixv.flow_control

•   To enable a flow control setting with sysctl:

        sysctl dev.ixv.<interface #>.fc=3

•   To disable flow control using sysctl:

        sysctl dev.ixv.<interface #>.fc=0

    NOTE:

•   The ixv driver requires flow control on both the port and link partner. If flow control is disabled on one of the sides, the port may appear to hang on heavy traffic.

•   For 82598 backplane cards entering 1 gigabit mode, flow control default behavior is changed to off. Flow control in 1 gigabit mode on these devices can lead to transmit hangs.

•   The VF driver does not have access to flow control. It must be managed from the host side.

  DMAC

Valid Range: 0, 41-10000

This parameter enables or disables the DMA Coalescing (DMAC) feature. Values are in microseconds and set the internal DMA Coalescing internal timer. DMAC is available on Intel(R) X550 (and later) based adapters.

DMA (Direct Memory Access) allows the network device to move packet data directly to the system's memory, reducing CPU utilization. However, the frequency and random intervals at which packets arrive do not allow the system to enter a lower power state. DMA Coalescing allows the adapter to collect packets before it initiates a DMA event. This may increase network latency but also increases the chances that the system will enter a lower power state. Turning on DMA Coalescing may save energy. DMA Coalescing must be enabled across all active ports in order to save platform power.

Interrupt Throttle Rate (ITR) should be set to dynamic. When ITR=0, DMA Coalescing is automatically disabled.

KNOWN ISSUES/TROUBLESHOOTING

  UDP Stress Test Dropped Packet Issue

Under small packet UDP stress with the ixv driver, the system may drop UDP packets due to socket buffers being full. Setting the driver Intel Ethernet Flow Control variables to the minimum may resolve the issue.

  Error message "ixvX: could not setup receive structures"

Attempting to configure larger MTUs with a large numbers of processors may generate the error message "ixvX: could not setup receive structures."

When using the ixv driver with RSS autoconfigured based on the number of cores (the default setting) and that number is larger than 4, increase the memory resources allocated for the mbuf pool as follows: Add the following to the sysctl.conf file for the system:

    kern.ipc.nmbclusters=262144
    kern.ipc.nmbjumbop=262144

  Lower than expected performance

Some PCIe x8 slots are actually configured as x4 slots. These slots have insufficient bandwidth for full line rate with dual port and quad port devices. In addition, if you put a PCIe v4.0 or v3.0-capable adapter into a PCIe v2.x slot, you cannot get full bandwidth. The driver detects this situation and writes one of the following messages in the system log:

    PCI-Express bandwidth available for this card is not sufficient for optimal
    performance. For optimal performance a x8 PCI-Express slot is required.

or:

    PCI-Express bandwidth available for this device may be insufficient for
    optimal performance. Please move the device to a different PCI-e link with
    more lanes and/or higher transfer rate.

If this error occurs, moving your adapter to a true PCIe v3.0 x8 slot will resolve the issue.

  "no PRT entry for x.x.INTx" error on pcib4 in dmesg

On systems that use legacy interrupts, you may see the following in dmesg:

    pci4: on pcib4
    pcib4: no PRT entry for <x>.0.INTA
    pcib4: no PRT entry for <x>.0.INTB

For example:

    pci4: on pcib4
    pcib4: no PRT entry for 3.0.INTA
    pcib4: no PRT entry for 3.0.INTB

To work around the issue, add the following lines to /boot/loader.conf, where <x> is the number found in dmesg message (either 3 or 4):

    hw.pci0.<x>.0.INTA.irq=16
    hw.pci0.<x>.0.INTB.irq=17

SUPPORT

For general information, go to the Intel support website at http://www.intel.com/support/.

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 freebsd@intel.com.

TRADEMARKS

Intel is a trademark or registered trademark of Intel Corporation or its subsidiaries in the United States and/or other countries.

Other names and brands may be claimed as the property of others.

AUTHOR
Intel

COPYRIGHT
1999 - 2024, Intel Corporation