Re: [PATCH net-next v2] net: pppoe: implement GRO support

[Felix Fietkau]

On 22.07.25 16:47, Paolo Abeni wrote:
> On 7/22/25 4:04 PM, Eric Dumazet wrote:
> > On Wed, Jul 16, 2025 at 1:14 AM Felix Fietkau <nbd@xxxxxxxx> wrote:
> > > Only handles packets where the pppoe header length field matches the exact
> > > packet length. Significantly improves rx throughput.
> > >
> > > When running NAT traffic through a MediaTek MT7621 devices from a host
> > > behind PPPoE to a host directly connected via ethernet, the TCP throughput
> > > that the device is able to handle improves from ~130 Mbit/s to ~630 Mbit/s,
> > > using fraglist GRO.
> > >
> > > Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
> > > ---
> >
> > Shouldn't we first add GSO support ?
>
> I *think* the current __skb_gso_segment() should be able to segment a
> pppoe GSO packet, as the pppoe header is static/constant, skb->mac_len
> will include both eth/pppoe and skb->protocol should be the actual L3.

If the packet is received on a ppp device, __skb_gso_segment works 
afterwards.
However, for the bridge forwarding case, Eric is correct. In this case, 
skb->protocol will not be the L3 protocol.

I will add GSO support in v3.

Thanks,

- Felix