[ofw] What is the current support level for QoS in WinOF?

[Diego Guella]

Hi Sean,

----- Original Message ----- 
>From: "Sean Hefty"
> >Is QoS supported in WinOF?
>
> Definitely not to the extent supported by the Linux stack.
>
>>Is QoS supported in Mellanox WinOF?
>>Alternatively, can I add a single Linux host to my fabric, just to run OFED
>>(and opensm) on it to get full QoS support? Are there some incompatibilities
>>between win-linux (about QoS)?
>
> I'm highly skeptical that the WinOF opensm supports QoS, but I don't know for
> certain.  Even using the OFED opensm, additional changes would still be needed
> to the WinOF host stack; for example, using new PathRecord fields.  There
> shouldn't be any incompatibilities, but the WinOF stack won't provide the SM
> with enough information to support more advanced QoS partitioning.
>
> You may be able to use the OFED opensm to achieve some level of QoS, depending
> on how you want things separated.  If you can separate QoS based on HCA ports,
> you might have more success than trying to separate different applications
> running on the same HCA port.

I do have urgent time-sensitive traffic, and non-urgent traffic.
The urgent traffic and the non-urgent traffic is generated from different hosts.
I would like to differentiate them by using different SL, then configure QoS to give maximum priority to the urgent time-sensitive 
traffic, and minimum priority to the non-urgent traffic.

Are you saying I can't do this in WinOF?
And I can't do that even adding a Linux host that runs opensm (OFED version)?

Traffic separation based on HCA port could be an option, but I need to think more about that.
What can you do with that kind of QoS?
Do you mark this HCA port as high-priority, that HCA port as low-priority, etc?
What happens when a high-pri port sends traffic to a low-pri port? And vice-versa?
What happens when a high-pri port sends traffic to a "normal" port (a port that is not marked as high-priority nor low-priority)?
I'm using only RDMA Write with Imm in my system, although I'm interested in what happens on all types of traffic.
If you know of a document that explains that, please let me know, I haven't found it by now.


Thanks,
Diego