From: Jakub Kicinski <kuba@xxxxxxxxxx> Date: Tue, 3 Oct 2023 05:35:19 -0700 > On Wed, 27 Sep 2023 09:51:09 +0200 Larysa Zaremba wrote: >> Implement functionality that enables drivers to expose VLAN tag >> to XDP code. >> >> VLAN tag is represented by 2 variables: >> - protocol ID, which is passed to bpf code in BE >> - VLAN TCI, in host byte order > > Sorry for a random chime-in but was there any discussion about > the validity of VLAN stripping as an offload? > > I always thought this is a legacy "Windows" thing which allowed > Windows drivers to operate on VLAN-tagged networks even before > the OS itself understood VLANs... Do people actually care about > having it enabled? On MIPS routers, I actually have some perf gains from having it enabled. So they do, I'd say. Mediatek even has DSA tag stripping. Both save you some skb->data push-pulls, csum corrections when CHECKSUM_COMPLETE, skb unsharing in some cases, reduce L3/L4 headers cacheline spanning etc. Thanks, Olek
