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

[Ilya Maximets <i.maximets@ovn.org>]

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.

> 
> 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>