[ofa-general] some comments/clarifications on ipoib/opensm re qos

[Or Gerlitz]

Yevgeny Kliteynik wrote:
> Let's look at the IPoIB (the real IPoIB, not the keyword).
> If I understood your previous main correctly, then IPoIB gets its SL from
> the multicast group only right? So what kind of PR queries does IPoIB do?
> Only to MGID? Suppose A wants to send something over IPoIB to B. How will
> it use the right SL? Does it take it from the mcast group, or does it do
> a PR query to SM for the dgid of node B (using the right pkey), and takes
> the SL that os returned in the PR responce?
Again, IPoIB does PQ only for unicast traffic, and it provides the 
following data/component mask bits to the SA 
<SGID,DGID,PKEY,NUMB_PATH,TRAFFIC_CLASS>, where the relevant info for 
the QoS scheme deployed today at the opensm is the pkey. So to deploy 
QoS for IPoIB one needs to set an SL for the partition.

Or.