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

[Hal Rosenstock]

Hi Diego,

On Wed, Mar 25, 2009 at 5:03 AM, Diego Guella
<diego.guella at sircomtech.com> wrote:
> Hi Hal,
>
>> From: "Hal Rosenstock"
>> On Tue, Mar 24, 2009 at 3:34 AM, Diego Guella wrote:
>>>>
>>>> From: "Sean Hefty"
>>>> 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.
>>
>> If you are expecting the SL to come from OpenSM, it would be best to
>> use the Linux OpenSM and likely the QoS Annex support but I don't know
>> enough about what you have in mind in terms of the end node Windows
>> ULPs and whether they use RDMA CM and/or CM or bypass them.
>
> I forgot to mention: I am using plain verbs. (Actually, I'm using IBAL).
> Connection estabilishment is done like in the ibv_pingpong_rc examples:
> communicating LID, QPN, ... data over sockets.

Then this support may be sufficient for you given you have a way to set SL.

> I forgot to mention that I am new to QoS too.
> I think I can achieve urgent vs non-urgent traffic distinction by using 2
> QPs, and setting different SLs to these QPs, in the INIT->RTR transition.
> Are there other ways to "mark" some traffic as high-priority vs
> low-priority?

SL is the way. It can be set in different ways based on the connection
type. For RC, it is bound to the QP.

The key will be setting the QoS parameters appropriately for your traffic.

One more note: QoS is supported on only certain hardware. You will
likely need to check with your vendor as to what hardware is
supported.

-- Hal

> Thanks for your help,
> Diego
>
>
>