Re: [Question] About bonding offload

[Andrew Lunn <andrew@lunn.ch>]

On Tue, Apr 11, 2023 at 09:47:14AM +0800, Liang Li wrote:
> Hi Everyone,
> 
> I'm a redhat network-qe and am testing bonding offload. e.g. gso,tso,gro,lro.
> I got two questions during my testing.
> 
> 1. The tcp performance has no difference when bonding GRO is on versus off.
> When testing with bonding, I always get ~890 Mbits/sec bandwidth no
> matter whether GRO is on.
> When testing with a physical NIC instead of bonding on the same
> machine, with GRO off, I get 464 Mbits/sec bandwidth, with GRO on, I
> get  897 Mbits/sec bandwidth.
> So looks like the GRO can't be turned off on bonding?
> 
> I used iperf3 to test performance.
> And I limited iperf3 process cpu usage during my testing to simulate a
> cpu bottleneck.
> Otherwise it's difficult to see bandwidth differences when offload is
> on versus off.
> 
> I reported a bz for this: https://bugzilla.redhat.com/show_bug.cgi?id=2183434
> 
> 2.  Should bonding propagate offload configuration to slaves?
> For now, only "ethtool -K bond0 lro off" can be propagated to slaves,
> others can't be propagated to slaves, e.g.
>   ethtool -K bond0 tso on/off
>   ethtool -K bond0 gso on/off
>   ethtool -K bond0 gro on/off
>   ethtool -K bond0 lro on
> All above configurations can't be propagated to bonding slaves.
> 
> I reports a bz for this: https://bugzilla.redhat.com/show_bug.cgi?id=2183777
> 
> I am using the RHEL with kernel 4.18.0-481.el8.x86_64.
 
Hi Liang

Can you reproduce these issues with a modern kernel? net-next, or 6.3?

The normal process for issues like this is to investigate with the
latest kernel, and then backport fixes to old stable kernels.

       Andrew