Re: [PATCH net-next v2] openvswitch: raise internal port TSO limit

[Eelco Chaudron <echaudro@redhat.com>]

On 16 Sep 2026, at 11:49, Ilya Maximets wrote:

> On 9/16/26 11:37 AM, Eelco Chaudron wrote:
>>
>>
>> On 16 Sep 2026, at 8:58, Wang Zhan wrote:
>>
>>> Set the internal port TSO limit to GSO_MAX_SIZE (512 KB), as for
>>> loopback and veth. This allows the admin/user to set a GSO limit up to
>>> this value, to use BIG TCP for traffic routed through the internal port.
>>>
>>> Only the capability limit changes: the IPv4 and IPv6 GSO and GRO limits
>>> remain at 64 KiB until changed by the administrator.
>>>
>>> Validation used a same-host test with a temporary OVS bridge, a veth pair,
>>> and a network namespace:
>>>
>>>   TCP client -> OVS internal -> OVS bridge -> veth -> TCP server
>>>
>>> The veth endpoints were BIG TCP capable throughout the test, and only the
>>> OVS internal port limits changed between 64 KiB and 524280 bytes. A single
>>> iperf3 3.19 TCP flow, run separately over IPv4 and IPv6 with six
>>> alternating runs per state (`-t 15 -O 5`, fixed CPU affinity and port
>>> tuple), increased throughput by 18.1% for IPv4 and 34.7% for IPv6:
>>>
>>>   protocol  BIG TCP off  BIG TCP on   CV off / on
>>>   TCP/IPv4  65.567 Gbps  77.420 Gbps  1.12% / 0.37%
>>>   TCP/IPv6  55.355 Gbps  74.568 Gbps  1.20% / 0.68%
>>>
>>> Assisted-by: LLM
>>
>> I think Ilya already mentioned this earlier, but the LLM tag means you need to
>> fill in the LLM model name you used.
>
> It looks like the rules changed recently, see:
>   816d9992d9ed ("coding-assistants: simplify attribution")
>
> So that's just a new acceptable format, which is fine.

Ok, missed that change :( So with that

Reviewed-by:  Eelco Chaudron <echaudro@redhat.com>

>>
>> The rest looks good to me.
>>
>> //Eelco
>>
>>> Signed-off-by: Wang Zhan <wang.zhan@smartx.com>
>>> ---
>>>
>>> v2:
>>> - add an empty line before netif_set_tso_max_size()
>>> - rebase net-next/main
>>> - cc all the maintainers
>>> v1: https://lore.kernel.org/20260910131635.780802-1-wang.zhan@smartx.com/
>>>
>>> ---
>>>  net/openvswitch/vport-internal_dev.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c
>>> index 125d310871e93..77a16d5ebd543 100644
>>> --- a/net/openvswitch/vport-internal_dev.c
>>> +++ b/net/openvswitch/vport-internal_dev.c
>>> @@ -117,6 +117,8 @@ static void do_setup(struct net_device *netdev)
>>>  	netdev->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
>>>  	netdev->hw_features = netdev->features;
>>>
>>> +	netif_set_tso_max_size(netdev, GSO_MAX_SIZE);
>>> +
>>>  	eth_hw_addr_random(netdev);
>>>  }
> Reviewed-by: Ilya Maximets <i.maximets@ovn.org>