On Thu, 5 Oct 2023 11:20:49 -0600 David Ahern wrote: > > Every time I'm involved in conversations about NIC datapath host > > interfaces I cringe at this stupid VLAN offload. Maybe I'm too > > daft to understand it's amazing value but we just shift 2B from > > the packet to the descriptor and then we have to worry about all > > the corner cases that come from vlan stacking :( > > 4B (vlan tci + protocol). > > VLAN stripping in S/W and pushing the header on Tx is measurable and > does have a noticeable performance impact. > > XDP programs need to co-exist with enabled offloads. If the tag is not > stripped, XDP program needs to handle it. If the tag is stripped, the > XDP program needs to access to the value. Well, I thought I'd ask :) I'm not opposed. But if either of you have the data on how much slower well-implemented Rx stripping in the driver is than putting the info in the descriptor, I'd be very interested. Tx is a different situation.
