Re: [PATCH] - gre: add eth_p_teb gro-handler for OVS with gre tunnels

[Ramu Ramamurthy <sramamur@linux.vnet.ibm.com>]

On 2015-10-12 16:47, Jesse Gross wrote:
> On Mon, Oct 12, 2015 at 3:26 PM, Ramu Ramamurthy
> <sramamur@linux.vnet.ibm.com> wrote:
>> 
>> Problem:
>> --------
>> 
>> When using OVS with GRE tunnels, and GRO is enabled on the nic,
>> We find that GRO doesnt really take effect. As a result, TCP stream
>> performance on a 10G nic is around 2-3Gbps.
>> 
>> Root Cause:
>> -----------
>> 
>> The protocol field set in GRE (by OVS) is ETH_P_TEB.
>> The code in gre_gro_receive() (gre_offload.c) calls
>> gro_find_receive_by_type() to determine a gro handler for the
>> ETH_P_TEB protocol. However, no such protocol is registered
>> at the device layer (only ETH_P_IP, ETH_P_IPV6, and mpls related
>> protocols are registered). Hence, GRO is skipped.
> 
> Why doesn't this work?
> 
> commit 9b174d88c257150562b0101fcc6cb6c3cb74275c
> Author: Jesse Gross <jesse@nicira.com>
> Date:   Tue Dec 30 19:10:15 2014 -0800
> 
>     net: Add Transparent Ethernet Bridging GRO support.
> 
>     Currently the only tunnel protocol that supports GRO with 
> encapsulated
>     Ethernet is VXLAN. This pulls out the Ethernet code into a proper 
> layer
>     so that it can be used by other tunnel protocols such as GRE and 
> Geneve.
> 
>     Signed-off-by: Jesse Gross <jesse@nicira.com>
>     Signed-off-by: David S. Miller <davem@davemloft.net>

Thanks, your commit fixes the same problem in the 4.x kernels. So the 
patch above is redundant.

We are using the 3.x kernels and thats why I could not see your fix in 
my tests.

We/distros would need to backport your fix to 3.x for us to consume it.