Re: ixgbe: ierrors counter spuriously increasing in DPDK 2.1

[Martin Weiser <martin.weiser@allegro-packets.com>]

On 04.11.15 16:54, Van Haaren, Harry wrote:
>> From: Martin Weiser [mailto:martin.weiser@allegro-packets.com]
>> Subject: Re: [dpdk-dev] ixgbe: ierrors counter spuriously increasing in DPDK 2.1
>> The
>> rx-error which showed up immediately after starting the interface is
>> gone since this was probably caused by mac_remote_errors. 
> Improvement - that's good.
>
>> But we still
>> see a huge number of rx-errors although all packets are received
>> properly and when looking at the extended stats those come from the
>> rx_l3_l4_xsum_error counter.
> That is useful information, good to know that statistic is the root cause.
>
>> In our setup we are dealing with lots of UDP traffic which does have the
>> UDP checksum set to 0 (which to my knowledge is allowed for UDP).
> Yes indeed checksum calculation for UDP is optional, and should be set to zero when not performed.
>
>> This
>> traffic seems to cause those rx_l3_l4_xsum_errors.
>> When doing the same
>> test with other NICs (e.g. XL710) no rx-errors are accounted.
> So this is a ixgbe bug, and listed in the errata, item 43 "Integrity Error Reported for IPv4/UDP Packets with Zero Checksum" in http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/82599-10-gbe-controller-spec-update.pdf 
>
>> For the generic stats interface I would prefer only packets that could
>> not be received to be accounted in the rx-error counter regardless of
>> the actual NIC. What do you think?
> Agreed. I've sent a patch that removes "xec", the register name for l3_l4_xsum_errors:
> http://dpdk.org/dev/patchwork/patch/8678/
>
> Would you test it please? -Harry
I have tested the patch and now everything looks good.

Best regards, Martin