[openib-general] IB mcast question
mshefty at ichips.intel.com
Mon Aug 14 14:30:14 PDT 2006
Steve Wise wrote:
> ib_multicast takes care of sending the join/leave info to the SA, right?
> It keeps track of _when_ to leave, for instance. So since opensm -is-
> getting the join and setting up the group, and the mcast packet is being
> passed to the first member who joined, then I don't think ib_multicast
> can mess up the subsequent members, can it?
It theory, it shouldn't mess up subsequent members. While the first join is
active, subsequent join / leave requests to that same group should be queued.
After the first join completes, subsequent joins should get a copy of the
MCMemberRecord that was returned by the SA.
(This is a slight simplification, with the actual operation determined by the
type of join operation that occurs. But for the RDMA CM, this is what should
> I'm new to IB mcast, so I'm learning, but it seems like the mthca
> firmware maybe isn't doing the right thing here.
This was my suspicion, but I couldn't be certain. It would help if anyone can
say that they've successfully tested this sort of multicast configuration. I.e.
two QPs from the same HCA in the same group.
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