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.\" $FreeBSD$
.\"
.Dd February 22, 2015
.Dt SFXGE 4
.Os
.Sh NAME
.Nm sfxge
.Nd "Solarflare 10Gb Ethernet adapter driver"
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device sfxge"
.Ed
.Pp
To load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
sfxge_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for 10Gb Ethernet adapters based on
Solarflare SFC9000 family controllers.
The driver supports jumbo
frames, transmit/receive checksum offload, TCP Segmentation Offload
(TSO), Large Receive Offload (LRO), VLAN checksum offload, VLAN TSO,
and Receive Side Scaling (RSS) using MSI-X interrupts.
.Pp
The driver allocates 1 receive queue, transmit queue, event queue and
IRQ per CPU up to a maximum of 64.
IRQ affinities should be spread out using
.Xr cpuset 1 .
Interrupt moderation may be controlled through the sysctl
.Va dev.sfxge.%d.int_mod
(units are microseconds).
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Pp
A large number of MAC, PHY and data path statistics are available
under the sysctl
.Va dev.sfxge.%d.stats .
The adapter's VPD
fields including its serial number are available under the sysctl
.Va dev.sfxge.%d.vpd .
.Sh HARDWARE
The
.Nm
driver supports all 10Gb Ethernet adapters based on Solarflare SFC9000
family controllers.
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
Actual values can be obtained using
.Xr sysctl 8 .
.Bl -tag -width indent
.It Va hw.sfxge.rx_ring
The maximum number of descriptors in a receive queue ring.
Supported values are: 512, 1024, 2048 and 4096.
.It Va hw.sfxge.tx_ring
The maximum number of descriptors in a transmit queue ring.
Supported values are: 512, 1024, 2048 and 4096.
.It Va hw.sfxge.tx_dpl_get_max
The maximum length of the deferred packet
.Dq get-list
for queued transmit packets (TCP and non-TCP), used only if the transmit
queue lock can be acquired.
If a packet is dropped, the
.Va tx_get_overflow
counter is incremented and the local sender receives ENOBUFS.
The value must be greater than 0.
.It Va hw.sfxge.tx_dpl_get_non_tcp_max
The maximum number of non-TCP packets in the deferred packet
.Dq get-list
, used only if the transmit queue lock can be acquired.
If a packet is dropped, the
.Va tx_get_non_tcp_overflow
counter is incremented and the local sender receives ENOBUFS.
The value must be greater than 0.
.It Va hw.sfxge.tx_dpl_put_max
The maximum length of the deferred packet
.Dq put-list
for queued transmit
packets, used if the transmit queue lock cannot be acquired.
If a packet is dropped, the
.Va tx_put_overflow
counter is incremented and the local sender receives ENOBUFS.
The value must be greater than or equal to 0.
.It Va hw.sfxge.N.max_rss_channels
The maximum number of allocated RSS channels for the Nth adapter.
If set to 0 or unset, the number of channels is determined by the number
of CPU cores.
.It Va hw.sfxge.lro.table_size
Size of the LRO hash table.
Must be a power of 2.
A larger table means we can accelerate a larger number of streams.
.It Va hw.sfxge.lro.chain_max
The maximum length of a hash chain.
If chains get too long then the lookup time increases and may exceed
the benefit of LRO.
.It Va hw.sfxge.lro.idle_ticks
The maximum time (in ticks) that a connection can be idle before it's LRO
state is discarded.
.It Va hw.sfxge.lro.slow_start_packets
Number of packets with payload that must arrive in-order before a connection
is eligible for LRO.
The idea is we should avoid coalescing segments when the sender is in
slow-start because reducing the ACK rate can damage performance.
.It Va hw.sfxge.lro.loss_packets
Number of packets with payload that must arrive in-order following loss
before a connection is eligible for LRO.
The idea is we should avoid coalescing segments when the sender is recovering
from loss, because reducing the ACK rate can damage performance.
.El
.Sh SUPPORT
For general information and support,
go to the Solarflare support website at:
.Pa https://support.solarflare.com .
.Sh SEE ALSO
.Xr arp 4 ,
.Xr netintro 4 ,
.Xr ng_ether 4 ,
.Xr vlan 4 ,
.Xr cpuset 1 ,
.Xr ifconfig 8
.Sh AUTHORS
The
.Nm
driver was written by
.An Philip Paeps
and
.An Solarflare Communications, Inc.