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

[Olivier MATZ]

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)

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