[dpdk-dev] [PATCH v3 0/3] enhance TX checksum command and csum forwarding engine

[Ananyev, Konstantin]

Hi Olivier,

> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz at 6wind.com]
> Sent: Wednesday, January 21, 2015 3:25 PM
> To: Liu, Jijiang; Ananyev, Konstantin
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v3 0/3] enhance TX checksum command and csum forwarding engine
> 
> Hi,
> 
> On 01/21/2015 04:12 AM, Liu, Jijiang wrote:
> >>>>> Ok, and why it should be our problem?
> >>>>> We have a lot of things done in a different manner then
> >>>>> linux/freebsd kernel drivers, Why now it became a problem?
> >>>>
> >>>> If linux doesn't need an equivalent flag for doing the same thing, it
> >>>> probably means we don't need it either.
> >>>
> >>> Probably yes .... Or probably not.
> >>> Why do we need to guess what was the intention of guys who wrote that
> >> part of linux driver?
> >>
> >> Because the dpdk looks very similar to that part of linux driver.
> >
> > A  guy from Intel  who have already confirmed that the NVGRE is not supported yet in Linux kernel.
> >
> > He said "So far as I know it is not yet supported and I have no information on when it will be."
> 
> I added the support of Ether over GRE, IP over GRE and IP over IP
> tunnels in csumonly to do the test. I ask the csum forward engine
> to calculate inner IP+TCP checksums, and outer IP (case 6 in [1]).
> Here are the results:
> 
> 1/ When I use I40E_TXD_CTX_UDP_TUNNELING:
> - vxlan: all checksums ok
> - eth over gre: all checksums ok
> - ip over gre: not transmitted by hw
> - ip over ip: all checksums wrong (set to 0 by hw)
> 
> 2/ When I use I40E_TXD_CTX_GRE_TUNNELING:
> - vxlan: checksums ok
> - eth over gre: all checksums ok
> - ip over gre: all checksums ok
> - ip over ip: all checksums wrong (set to 0 by hw)
> 
> 3/ When I use 00b:
> - vxlan: all checksums ok
> - eth over gre: all checksums ok
> - ip over gre: all checksums ok
> - ip over ip: checksums wrong (set to 0 by hw)

Wow, so there is absolutely no difference in results for L4TUNT=2(GRE) and L4TUNT=0, right?
And IP over IP doesn't work at all?
I suppose you set L4TUNLEN as described in spec for each case, right?
That looks really weird to me and as I can see completely contradicts with what spec.
I suppose we'll need to reproduce all that tests on our HW too.
Could you send to us a patch with your changes, so we can try same thing?
Or just a dump of TDD and TCD values for each case. 
Konstantin

> 
> All the ip over ip tests do not work yet for an unknown reason.
> There is maybe something wrong in my app or in the driver
> (although the registers looks consistent with the datasheet).
> 
> I think we could use 3/ for all tunnels, because the ipip case
> is supposed to work according to the datasheet, and all other cases
> work too.
> 
> It would allow to remove the UDP_TUNNELING flag from mbuf API.
> 
> I will send a RFC patch that provides the API change and this new
> feature in csum forward engine, with full tests on ixgbe and i40e
> and explanations for all changes.
> 
> Regards,
> Olivier
> 
> [1] http://dpdk.org/ml/archives/dev/2015-January/011127.html