table of contents
VTNET(4) | Device Drivers Manual | VTNET(4) |
NAME¶
vtnet
—
VirtIO Ethernet driver
SYNOPSIS¶
To compile this driver into the kernel, place the following lines in your kernel configuration file:device vtnet
if_vtnet_load="YES"
DESCRIPTION¶
Thevtnet
device driver provides support for
VirtIO Ethernet devices.
If the hypervisor advertises the appreciate features, the
vtnet
driver supports TCP/UDP checksum
offload for both transmit and receive, TCP segmentation offload (TSO), TCP
large receive offload (LRO), and hardware VLAN tag stripping/insertion
features, as well as a multicast hash filter, as well as Jumbo Frames (up to
9216 bytes), which can be configured via the interface MTU setting. Selecting
an MTU larger than 1500 bytes with the
ifconfig(8) utility configures the adapter to
receive and transmit Jumbo Frames.
For more information on configuring this device, see
ifconfig(8).
LOADER TUNABLES¶
Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5).- hw.vtnet.csum_disable
- hw.vtnet.X.csum_disable
- This tunable disables receive and send checksum offload. The default value is 0.
- hw.vtnet.tso_disable
- hw.vtnet.X.tso_disable
- This tunable disables TSO. The default value is 0.
- hw.vtnet.lro_disable
- hw.vtnet.X.lro_disable
- This tunable disables LRO. The default value is 0.
- hw.vtnet.mq_disable
- hw.vtnet.X.mq_disable
- This tunable disables multiqueue. The default value is 0.
- hw.vtnet.mq_max_pairs
- hw.vtnet.X.mq_max_pairs
- This tunable sets the maximum number of transmit and receive queue pairs. Multiple queues are only supported when the Multiqueue feature is negotiated. This driver supports a maximum of 8 queue pairs. The number of queue pairs used is the lesser of the maximum supported by the driver and the hypervisor, the number of CPUs present in the guest, and this tunable if not zero. The default value is 0.
SEE ALSO¶
arp(4), netintro(4), ng_ether(4), virtio(4), vlan(4), ifconfig(8)HISTORY¶
Thevtnet
driver was written by
Bryan Venteicher ⟨bryanv@FreeBSD.org⟩. It first appeared in FreeBSD 9.0.
CAVEATS¶
Thevtnet
driver only supports LRO when the
hypervisor advertises the mergeable buffer feature.January 22, 2012 | Debian |