NAME

txgbe -This file describes the Linux* Base Driver for the 10 Gigabit Family of Adapters.

SYNOPSIS

modprobe txgbe [<option>=<VAL1>,<VAL2>,...]

DESCRIPTION

This driver is intended for 2.6.x or later kernels. This driver includes support for any 64 bit Linux supported system, including Itanium(R)2, x86_64, PPC64,ARM, etc.

This driver is only supported as a loadable module at this time. WangXun is not supplying patches against the kernel source to allow for static linking of the drivers.

A version of the driver may already be included by your distribution and/or the kernel.org kernel.

For questions related to hardware requirements, refer to the documentation supplied with your WangXun adapter. All hardware requirements listed apply to use with Linux.

OPTIONS

The following optional parameters are used by entering them on the command line with the modprobe command. For example:

modprobe txgbe InterruptThrottleRate=16000,16000

RSS

Valid Range: 0-64

0 = Assign up to the lesser value of the number of CPUs or the number of queues

X = Assign X queues, where X is less than or equal to the maximum number of queues (64 queues).

RSS also effects the number of transmit queues allocated on 2.6.23 and newer kernels with CONFIG_NETDEVICES_MULTIQUEUE set in the kernel .config file. CONFIG_NETDEVICES_MULTIQUEUE only exists from 2.6.23 to 2.6.26. Other options enable multiqueue in 2.6.27 and newer kernels.

MQ - Multiqueue

Valid Range: 0, 1

0 = Disables Multiple Queue support 1 = Enabled Multiple Queue support (a prerequisite for RSS)

IntMode

Valid Range: 0-2 (0 = Legacy Int, 1 = MSI and 2 = MSI-X)

IntMode controls allow load time control over the type of interrupt registered for by the driver. MSI-X is required for multiple queue support, and some kernels and combinations of kernel .config options will force a lower level of interrupt support.

InterruptThrottleRate

Valid Range: 0=off 1=dynamic <min_ITR>-<max_ITR>

Interrupt Throttle Rate controls the number of interrupts each interrupt vector can generate per second. Increasing ITR lowers latency at the cost of increased CPU utilization, though it may help throughput in some circumstances.

0 = Setting InterruptThrottleRate to 0 turns off any interrupt moderation
and may improve small packet latency. However, this is generally not
suitable for bulk throughput traffic due to the increased CPU utilization
of the higher interrupt rate.
NOTES:
- disabling InterruptThrottleRate
will also result in the driver disabling HW RSC.
- disabling InterruptThrottleRate will also
result in disabling LRO (Large Receive Offloads).

1 = Setting InterruptThrottleRate to Dynamic mode attempts to moderate
interrupts per vector while maintaining very low latency. This can
sometimes cause extra CPU utilization. If planning on deploying txgbe
in a latency sensitive environment, this parameter should be considered.

<min_ITR>-<max_ITR> = 980-500000
Setting InterruptThrottleRate to a value greater or equal to <min_ITR>
will program the adapter to send at most 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.

LLIPort

Valid Range: 0-65535

LLI is configured with the LLIPort command-line parameter, which specifies which TCP port should generate Low Latency Interrupts.

For example, using LLIPort=80 would cause the board to generate an immediate interrupt upon receipt of any packet sent to TCP port 80 on the local machine.

WARNING: Enabling LLI can result in an excessive number of interrupts/second that may cause problems with the system and in some cases may cause a kernel panic.

LLISize

Valid Range: 0-1500

LLISize causes an immediate interrupt if the board receives a packet smaller than the specified size.

LLIEType

Valid Range: 0-0x8FFF

This parameter specifies the Low Latency Interrupt (LLI) Ethernet protocol type.

LLIVLANP

Valid Range: 0-7

This parameter specifies the LLI on VLAN priority threshold.

FdirPballoc

Valid Range: 1-3

Specifies the Flow Director allocated packet buffer size. 1 = 64k 2 = 128k 3 = 256k

AtrSampleRate

Valid Range: 0-255

This parameter is used with the Flow Director and is the software ATR transmit packet sample rate. For example, when AtrSampleRate is set to 20, every 20th packet looks to see if the packet will create a new flow. A value of 0 indicates that ATR should be disabled and no samples will be taken.

LRO

Valid Range: 0(off), 1(on)

Large Receive Offload (LRO) is a technique for increasing inbound throughput of high-bandwidth network connections by reducing CPU overhead. It works by aggregating multiple incoming packets from a single stream into a larger buffer before they are passed higher up the networking stack, thus reducing the number of packets that have to be processed. LRO combines multiple Ethernet frames into a single receive in the stack, thereby potentially decreasing CPU utilization for receives.

TXGBE_NO_LRO is a compile time flag. The user can enable it at compile time to add support for LRO from the driver. The flag is used by adding CFLAGS_EXTRA="-DTXGBE_NO_LRO" to the make file when it's being compiled. # make CFLAGS_EXTRA="-DTXGBE_NO_LRO" install

You can verify that the driver is using LRO by looking at these counters in ethtool:

- lro_aggregated - counts total packets that were combined

- lro_flushed - counts the number of packets flushed out of LRO

NOTE: IPv6 and UDP are not supported by LRO.

vxlan_rx

Valid Range: 0(Disable), 1(Enable)

Enable/disable support for VXLAN rx checksum offload

CloudSwitch

Valid Range: 0-1 0 = disable Cloud Switch, 1 = enable Cloud Switch

Cloud Switch mode

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 eth<x> mtu 9000 up

NOTES: - The maximum MTU setting for Jumbo Frames is 9710. This value coincides
with the maximum Jumbo Frames 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. - 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. See the section "Jumbo Frames" in the Readme.

SUPPORT

For additional information regarding building and installation, see the README included with the driver. For general information, go to the WangXun support website at: www.trustnetic.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 linux.nic@trustnetic.com.