Page MenuHomeFreeBSD
Files F144245661

D52684.diff
No OneTemporary
Actions

D52684.diff
View Options

diff --git a/share/man/man4/vtnet.4 b/share/man/man4/vtnet.4
--- 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 26, 2025
+.Dd September 30, 2025
.Dt VTNET 4
.Os
.Sh NAME
@@ -54,6 +54,18 @@
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
@@ -94,8 +106,8 @@
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.
@@ -119,11 +131,11 @@
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.
diff --git a/sys/dev/virtio/network/if_vtnet.c b/sys/dev/virtio/network/if_vtnet.c
--- a/sys/dev/virtio/network/if_vtnet.c
+++ b/sys/dev/virtio/network/if_vtnet.c
@@ -281,7 +281,7 @@
SYSCTL_INT(_hw_vtnet, OID_AUTO, tso_disable, CTLFLAG_RDTUN,
&vtnet_tso_disable, 0, "Disables TSO");
-static int vtnet_lro_disable = 0;
+static int vtnet_lro_disable = 1;
SYSCTL_INT(_hw_vtnet, OID_AUTO, lro_disable, CTLFLAG_RDTUN,
&vtnet_lro_disable, 0, "Disables hardware LRO");

File Metadata

Mime Type
text/plain
Expires
Sun, Feb 8, 1:34 AM (18 h, 24 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
28462335
Default Alt Text
D52684.diff (2 KB)

Event Timeline