Sean Hefty wrote: > Today, userspace support for SA related operations is limited to the libibmad > interface, which supports sending and receiving MADs only. I've been assigned > with the task of exposing multicast and informinfo support to userspace. > Specifically, the following functionality is needed: > > 1. Join a multicast group - needs to use the ib_sa multicast capability. > 2. Receive notification of multicast errors. > 3. Leave a multicast group. > 4. Register to receive SA events - needs to use the ib_sa notice capability. > 5. Receive notification of events. > 6. Deregister from SA events. > > Are there any preferences for how this is added?
I'm a user; I can't comment on how this is implemented, but I'm very interested in what the API will look like. I think I discussed this on-list before, but a big feature for me (Open MPI) is to be able to request and join an unused multicast group. The exact address (or format, i.e. IP or MGID/MLID) of the group is not important as long as I can query it and pass it on out-of-band to peers. This avoids hard-coding of multicast addresses and/or outside (MPI user) input, which could result in multiple MPI jobs unknowingly using the same multicast group. The other big concern is control over which hca/port is joined to a multicast group -- IIRC this was a problem I had with the RDMA CM. Open MPI specifically tends to open every available network interface (multiple IB ports, as well as say GM/IB/TCP together) for bandwidth aggregation and failover purposes, so controlling which interfaces data goes out over is important. I hope this is useful information -- let me know if there is more input I can provide, or testing I can do. Andrew _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
