On Tue, 2006-08-15 at 16:07, Steve Wise wrote: > On Tue, 2006-08-15 at 12:39 -0700, Sean Hefty wrote: > > >Why are these separated? Isn't an address handle needed for each > > >destination QP? If so, then why is the remote qpn/qkey also needed to > > >transmit a datagram? > > > > The address handle doesn't include QPN/QKey information. Maybe think of > > them > > more as specifying the path to some port. > > > > Ok. > > >From what I can tell via experimentation, the qkey of the mcast group > doesn't need to have any relation to the qkeys of the qps.
That may be what is happening but I don't think that is correct (per the IBA spec). > I was able to create a mcast group with the mc qkey==0xe00a0a0a, Don't we need to be careful about controlled Q_Keys as well ? -- Hal > and 3 apps joined this group, but their qp qkeys were 0 (I changed > ucma_init_ud_qp() to set the qp qkey to 0). One app sent to the mcgroup > ah/qkey/qpn and the other two received the packet. Does that make > sense? > > So maybe all we need is the concept of REUSE_PORT to allow multiple > librdma users to create cm_ids with the same local port. currently this > isn't allowed. If we do this, then all processes that want to exchange > mcast packets would create cm_ids and do rdma_resolve_addr() with the > same src port number on all systems. > > Senders send to the ah/remote_qpn/remote_qkey of the mcast group. This > routes packets to all IB ports that have subscribers. Then since the > sender's qp has the same qkey as all the group participants each qp will > receive a copy of the packet. > > The mcast setup code in librdma doesn't need to change. IE the qkey can > remain the ip mcast address. > > I think this will work. It is similar to UDP/IP/MCAST... > > Or am I all wet? > > whatchathink? > > > > _______________________________________________ > openib-general mailing list > [email protected] > http://openib.org/mailman/listinfo/openib-general > > To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general > _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
