On Sat, Jul 08, 2023 at 05:15:26PM +0300, Alexander Bluhm wrote:
> I am not aware of any more limitations when enabling LRO for TCP
> in the network drivers. The feature allows to receive agregated
> packets larger than the MTU. Receiving TCP streams becomes much
> faster.
>
> As the network hardware is not aware whether a packet is received
> locally or forwarded, everything is aggregated. In case of forwarding
> it is split on output to packets not larger than the original
> packets. So path MTU discovery should still work. If the outgoing
> interface supports TSO, the packet is chopped in hardware.
>
> Currently only ix(4) and lo(4) support LRO, and ix(4) is limited
> to IPv4 and newer than the old 82598 model. If the interface is
> added to a bridge(4) or aggr(4), LRO is automatically disabled.
I guess you mean veb(4) not aggr(4). We just avoid the in heritage
of the LRO capability in aggr(4) but are using the feature.
> So in case you possess any ix(4) hardware or do funky pf routing
> on lo(4) please run this diff. If you encounter problems, report
> and turn LRO off per interface with ifconfig -tcplro.
Diff looks fine to me. I just would keep mentioning the default
behavior in the manpage like this:
ok jan@
Index: sbin/ifconfig/ifconfig.8
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.8,v
retrieving revision 1.397
diff -u -p -r1.397 ifconfig.8
--- sbin/ifconfig/ifconfig.8 7 Jun 2023 18:42:40 -0000 1.397
+++ sbin/ifconfig/ifconfig.8 10 Jul 2023 11:54:47 -0000
@@ -517,9 +517,9 @@ It is not possible to use LRO with inter
or
.Xr tpmr 4 .
Changing this option will re-initialize the network interface.
+LRO is enabled by default.
.It Cm -tcplro
Disable LRO.
-LRO is disabled by default.
.It Cm up
Mark an interface
.Dq up .
> Index: sys/dev/pci/if_ix.c
> ===================================================================
> RCS file: /data/mirror/openbsd/cvs/src/sys/dev/pci/if_ix.c,v
> retrieving revision 1.198
> diff -u -p -r1.198 if_ix.c
> --- sys/dev/pci/if_ix.c 8 Jul 2023 09:01:30 -0000 1.198
> +++ sys/dev/pci/if_ix.c 8 Jul 2023 13:51:26 -0000
> @@ -1925,8 +1925,10 @@ ixgbe_setup_interface(struct ix_softc *s
> ifp->if_capabilities |= IFCAP_CSUM_IPv4;
>
> ifp->if_capabilities |= IFCAP_TSOv4 | IFCAP_TSOv6;
> - if (sc->hw.mac.type != ixgbe_mac_82598EB)
> + if (sc->hw.mac.type != ixgbe_mac_82598EB) {
> + ifp->if_xflags |= IFXF_LRO;
> ifp->if_capabilities |= IFCAP_LRO;
> + }
>
> /*
> * Specify the media types supported by this sc and register
> Index: sys/net/if_loop.c
> ===================================================================
> RCS file: /data/mirror/openbsd/cvs/src/sys/net/if_loop.c,v
> retrieving revision 1.95
> diff -u -p -r1.95 if_loop.c
> --- sys/net/if_loop.c 2 Jul 2023 19:59:15 -0000 1.95
> +++ sys/net/if_loop.c 8 Jul 2023 13:51:26 -0000
> @@ -172,11 +172,11 @@ loop_clone_create(struct if_clone *ifc,
> ifp->if_softc = NULL;
> ifp->if_mtu = LOMTU;
> ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
> - ifp->if_xflags = IFXF_CLONED;
> + ifp->if_xflags = IFXF_CLONED | IFXF_LRO;
> ifp->if_capabilities = IFCAP_CSUM_IPv4 |
> IFCAP_CSUM_TCPv4 | IFCAP_CSUM_UDPv4 |
> IFCAP_CSUM_TCPv6 | IFCAP_CSUM_UDPv6 |
> - IFCAP_LRO;
> + IFCAP_LRO | IFCAP_TSOv4 | IFCAP_TSOv6;
> ifp->if_rtrequest = lortrequest;
> ifp->if_ioctl = loioctl;
> ifp->if_input = loinput;
> Index: sbin/ifconfig/ifconfig.8
> ===================================================================
> RCS file: /data/mirror/openbsd/cvs/src/sbin/ifconfig/ifconfig.8,v
> retrieving revision 1.397
> diff -u -p -r1.397 ifconfig.8
> --- sbin/ifconfig/ifconfig.8 7 Jun 2023 18:42:40 -0000 1.397
> +++ sbin/ifconfig/ifconfig.8 7 Jul 2023 19:57:09 -0000
> @@ -519,7 +519,6 @@ or
> Changing this option will re-initialize the network interface.
> .It Cm -tcplro
> Disable LRO.
> -LRO is disabled by default.
> .It Cm up
> Mark an interface
> .Dq up .
>
