On 2021/12/05 19:22, Yury Shefer wrote:
> Hi all,
>
> I have quad-port Intel ET2 NIC based on 82576[1] controller. The manual
> says that hardware VLAN tagging should be supported but ifconfig output
> shows VLAN_MTU only in hwfeatures on OpenBSD 7.0. How do I check if 802.1Q
> tagging is offloaded or not? And if it's not - does it matter at 1Gbps
> speeds on 3 Ghz CPU?
>
> $ dmesg | grep em0
> em0 at pci11 dev 0 function 0 "Intel 82576" rev 0x01: msi, address
> 90:e2:ba:84:64:14
>
> $ ifconfig em0 hwfeatures
> em0: flags=808843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,AUTOCONF4> mtu 1500
Not supported by the driver with 82576 - you would see VLAN_HWTAGGING here:
> hwfeatures=10<VLAN_MTU> hardmtu 9216
^^^^^
>From if_em.c:
1949 #if NVLAN > 0
1950 if (sc->hw.mac_type != em_82575 && sc->hw.mac_type != em_82580 &&
1951 sc->hw.mac_type != em_82576 &&
1952 sc->hw.mac_type != em_i210 && sc->hw.mac_type != em_i350)
1953 ifp->if_capabilities |=
IFCAP_VLAN_HWTAGGING;
1954 #endif
>From commit log:
----------------------------
revision 1.242
date: 2010/08/03 16:21:52; author: jsg; state: Exp; lines: +3 -2;
Disable hardware VLAN stripping/insertion on 8257[56] for now.
While
stripping works insertion seems to have trouble in certain conditions,
which needs to be fixed before we want to enable hardware
support for this.
ok deraadt@
----------------------------
You are best placed to tell whether it matters for your system. Is it fast
enough already? Bandwidth doesn't matter all that much, packets-per-second is
more important.
