netdev - Re: [RFC PATCH 4/5] bnxt: Add support for segmentation of tunnels with outer checksums

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Date:	Wed, 27 Apr 2016 08:21:46 -0700
From:	Alexander Duyck <alexander.duyck@...il.com>
To:	Michael Chan <michael.chan@...adcom.com>
Cc:	Alexander Duyck <aduyck@...antis.com>, eugenia@...lanox.com,
	Bruce W Allan <bruce.w.allan@...el.com>,
	Saeed Mahameed <saeedm@...lanox.com>,
	Netdev <netdev@...r.kernel.org>,
	intel-wired-lan <intel-wired-lan@...ts.osuosl.org>,
	Ariel Elior <ariel.elior@...gic.com>,
	Michael Chan <mchan@...adcom.com>
Subject: Re: [RFC PATCH 4/5] bnxt: Add support for segmentation of tunnels
 with outer checksums

On Tue, Apr 26, 2016 at 10:55 PM, Michael Chan
<michael.chan@...adcom.com> wrote:
> On Tue, Apr 19, 2016 at 12:06 PM, Alexander Duyck <aduyck@...antis.com> wrote:
>> This patch assumes that the bnxt hardware will ignore existing IPv4/v6
>> header fields for length and checksum as well as the length and checksum
>> fields for outer UDP and GRE headers.
>>
>> I have no means of testing this as I do not have any bnx2x hardware but
>> thought I would submit it as an RFC to see if anyone out there wants to
>> test this and see if this does in fact enable this functionality allowing
>> us to to segment tunneled frames that have an outer checksum.
>>
>> Signed-off-by: Alexander Duyck <aduyck@...antis.com>
>
> Hi Alex, I just did a very quick test of this patch on our bnxt
> hardware and it seemed to work.
>
> I created a vxlan endpoint with udpcsum enabled and I saw TSO packets
> getting through.  I've verified that our hardware can be programmed to
> either ignore outer UDP checksum or to calculate it.  Current default
> is to ignore ipv4 UDP checksum and calculate ipv6 UDP checksum.
> Thanks.

Are you saying you can natively support UDP tunnel with outer checksum
offload then?

I'm just trying to sort out if you actually need to have the partial
segmentation offload support or if we can handle it in hardware.  Also
is there any documentation you could point me to that might help to
clarify what the hardware does/doesn't support so that I could improve
upon this patch in order to make sure we are getting the most bang for
the buck in terms of the features that can be offloaded by hardware?

Thanks.

- Alex