diff options
Diffstat (limited to 'share/man/man4/vtnet.4')
| -rw-r--r-- | share/man/man4/vtnet.4 | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/share/man/man4/vtnet.4 b/share/man/man4/vtnet.4 index 0594ca70e99a..fd41b36882a6 100644 --- a/share/man/man4/vtnet.4 +++ b/share/man/man4/vtnet.4 @@ -22,7 +22,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd September 16, 2025 +.Dd September 30, 2025 .Dt VTNET 4 .Os .Sh NAME @@ -54,6 +54,20 @@ TCP segmentation offload (TSO), TCP large receive offload (LRO), hardware VLAN tag stripping/insertion features, a multicast hash filter, as well as Jumbo Frames (up to 9216 bytes), which can be configured via the interface MTU setting. +.Pp +Two flavors of TCP LRO are supported: +Hardware TCP LRO, which is performed by the host providing TCP segments larger +than the MTU to the guest, and Software TCP LRO, which is performed by the +network stack of the guest processing TCP segments in an optimized way. +Only one flavour of TCP LRO should be used. +Since hardware TCP LRO can have bad interactions with IP forwarding and +software TCP LRO mitigates several drawbacks of hardware TCP LRO, the default +setting is to disable hardware TCP LRO. +See the loader tunable +.Va hw.vtnet. Ns Ar X Ns Va .lro_disable . +.Pp +TCP/UDP receive checksum offload cannot be configured independently for IPv4 +and IPv6. Selecting an MTU larger than 1500 bytes with the .Xr ifconfig 8 utility configures the adapter to receive and transmit Jumbo Frames. @@ -92,8 +106,8 @@ This tunable disables TCP segmentation offloading. The default value is 0. .It Va hw.vtnet.lro_disable .It Va hw.vtnet. Ns Ar X Ns Va .lro_disable -This tunable disables large receive offload. -The default value is 0. +This tunable disables hardware TCP LRO. +The default value is 1. .It Va hw.vtnet.mq_disable .It Va hw.vtnet. Ns Ar X Ns Va .mq_disable This tunable disables multiqueue. @@ -117,11 +131,11 @@ This tunable sets the number of RX segments processed in one pass. The default value is 1024. .It Va hw.vtnet.lro_entry_count .It Va hw.vtnet. Ns Ar X Ns Va .lro_entry_count -This tunable sets the software LRO entry count. +This tunable sets the software TCP LRO entry count. The default value is 128, the minimum value is 8. .It Va hw.vtnet.lro_mbufq_depth .It Va hw.vtnet. Ns Ar X Ns Va .lro_mbufq_depth -This tunable sets the depth of the software LRO mbuf queue. +This tunable sets the depth of the software TCP LRO mbuf queue. The default value is 0. .It Va hw.vtnet.altq_disable This tunable disables ALTQ support, allowing the use of multiqueue instead. |