RE: [PATCH] net/iavf: fix checksum offloading

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Tuesday, August 22, 2023 1:29 AM
> To: Zhang, Qi Z <qi.z.zhang@intel.com>
> Cc: dev@dpdk.org; echaudro@redhat.com; mkp@redhat.com;
> stable@dpdk.org; Wu, Jingjing <jingjing.wu@intel.com>; Xing, Beilei
> <beilei.xing@intel.com>; Doherty, Declan <declan.doherty@intel.com>; Sinha,
> Abhijit <abhijit.sinha@intel.com>; Nicolau, Radu <radu.nicolau@intel.com>
> Subject: Re: [PATCH] net/iavf: fix checksum offloading
> 
> On Mon, Aug 21, 2023 at 1:54 PM Zhang, Qi Z <qi.z.zhang@intel.com> wrote:
> > > Subject: [PATCH] net/iavf: fix checksum offloading
> > >
> > > The only presence of RTE_MBUF_F_TX_IPV4 can't be used as an
> > > indicator that a checksum offload has been requested by an application.
> >
> > According to current implementation, actually the only presence of
> RTE_MBUF_F_TX_IPV4 will cause IIPT = 10b, this scenario corresponds to an
> 'IPv4 packet with no IP checksum offload,' according to datasheet.
> > So, I assume in this situation, the PMD  continues to operate under the
> assumption that the application has not requested checksum offloading.
> >
> > Could you share more insight what is the failure,  maybe we can perform a
> more comprehensive investigation?
> 
> I think the missing piece is that OVS passes a l2_len == l3_len == 0.
> In our tests, we could see that tx_errors get incremented for each failed packet
> to transmit.

OK, do you think to ignore RTE_MBUF_F_TX_IPV4 when l3_len = 0 is a better fix?

> 
> 
> --
> David Marchand