Re: NAT performance regression caused by vlan GRO support

[Eric Dumazet]

On 04/05/2019 03:51 AM, Florian Westphal wrote:
> Toke Høiland-Jørgensen <t...@redhat.com> wrote:
>> As a first approximation, maybe just:
>>
>> if (!has_hardware_cksum_offload(netdev) && link_rate(netdev) <= 1Gbps)
>>   disable_gro();
> 
> I don't think its a good idea.  For local delivery case, there is no
> way to avoid the checksum cost, so might as well have GRO enabled.
> 

We might add a sysctl or a way to tell GRO layer :

Do not attempt checksumming if forwarding is enabled on the host.

Basically GRO if NIC has provided checksum offload.