Re: AW: AW: AW: IPoIB GRO

[Erez Shitrit <erezsh-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

>> I see. This didn't happen on our setups here since we tests with
>> newer cards (ConnectX2/3/3-pro).
>> For ConnectX1 (A0) and this firmware that you are using smells
>> like something goes wrong. If possible, I would change to newish
>> card.
> No problem with that. My journey up to here was hard but very
> interesting. Especially when you expect everything in the system
> to be consistent and new speedups with every new kernel or
> driver version. Encountering a throughput drop of nearly 50%
> with the upgrade of our NFS servers I was challenged.
>
> With TSO disabled on our old cards I'm back to LRO speeds and
> I'm more than happy with that.
>
> Just a final clarification for the interested reader: Are the TCP Ids
> in an TSO setup generated through firmware or in the software
> stack? And if in firmware: How does the card know how to
> increase them? I would expect that it only works with IB packets
> and does not know of the IP encapsulation.
The card (HW) knows how to deal with IP packets, the card is configured 
via the FW to increase the ip-id for each ip packet that it is part of 
the full message.

so, to summarize:
The HW does the work (truncates the big ip packet to series of ip 
packets, each with the relevant mtu size and increases the ip-id for each)
The FW enables that work on the HW
the FW in A0 card doesn't enable that option for the HW.

>
> Best regards.
>
> Markus

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