On Thu, 2005-12-01 at 01:07, Eitan Zahavi wrote: > > > > > > The bottom line: > > > We are missing 3 agents in the OpenIB stack: > > > InformInfo - handling registrations and Report dispatching > > > > These are not currently used. > [EZ] They are by SRP initiator.
Not the SRP initiator in OpenIB svn as far as I can tell. > > > ServiceRecord - tracks registrations > > > > ServiceRecord is implemented in sa_query (and was used by AT/uAT but > > that is largely historical now) > > > > > Multicast Join/Leave - tracking registrations to multicast groups > and > > > ref-counting > > > > > > All these agents should be able to cleanup dead client registrations > and > > > also provide re-registration in case of SM ClientReregistration > event. > > > > In OpenIB, any Set of PortInfo (which includes ClientReregister) > > currently causes a (coarse) event (LID change) which causes IPoIB > client > > to reregister its multicasts registrations with the SA. > > > > > Please see below > > > > > > > > > > It seems the IBTA intent was that the IB driver will be > responsible > > > for maintaining > > > > the list of clients > > > > > registered to each group. > > > > > > > > Yes, the end node is responsible for tracking the registrations > within > > > > the node and fabricating responses when the node does not want to > > > leave. > > > > Is delete a different case though ? > > > [EZ] No it is not. Delete of multicast group is really the last > leave. > > > > There is an explicit delete. While it shouldn't be needed to be > forced, > > there is always some scenario where this is useful. > [EZ] To my best knowledge any leave is a "delete" so there is no way for > any client to force other members out of a group. It can only leave > itself. The delete will happen when the last will leave. Yes, you are right, other than the last full member (join state) rule. > > > > > But the IB core does not track what clients registered (through > SA > > > requests) to a > > > > particular multicast group. > > > > > The first client to leave the group causes the rest (of the > clients) > > > to be disconnected. > > > > > > > > This is an implementation issue IMO and applies to other > subscriptions > > > > too (not just limited to multicast). > > > [EZ] I agree it is an implementation issue. I hope it will get > > > implemented in OpenIB. > > > > It will. It's a question of priorities and timing. > > > > > > > My proposal is to provide an API for such registrations at both > user > > > and kernel and > > > > track the requesting processes. > > > > > Cleanup is also required both by process and kernel module > > > granularity. > > > > > > > > Is the API the SA client request itself for this ? Shouldn't the > > > > tracking be done there (within sa_query.c) ? > > > [EZ] It will be hard to sniff the MADs (especially user level) for > all > > > the registration flows. > > > > It's not the sniffing which is hard but perhaps identifying which > client > > (and reference counting). > > > > > So I propose we should have > > > > ib_join/ib_leave/ib_reg_svc/ib_unreg_svc/ib_reg_inform/ib_unreg_inform. > > > Both in user land and in kernel. > > > > I think this is TBD and the API would be discussed on this list first > > prior to any implementation. > > > > > > > BTW: The same API could also handle "Client Reregistration" for > > > multicast groups, > > > > > > > > Client reregistration is for all subscriptions (including > > > ServiceRecords > > > > and events as well). > > > [EZ] Yes exactly. I believe similar problem exists for all > > > registrations. > > > > > > > > > such that we could avoid the need to have that code duplicated > by > > > every client. > > > > > > > > I'm missing how client reregistration would help here. Can you > > > elaborate > > > > ? > > > [EZ] It is related to the reference tracking: > > > If a kernel module tracks all registrations to refcount them and > perform > > > cleanup, it could with similar effort also send the - > re-registration in > > > the event of SM change ... > > > > Sure, there are multiple ways to skin the same cat. > > > > > > > > > > > But this refers to yet another API that is missing: Report > > > dispatching which deserves > > > > its own > > > > > mail... > > > > > > > > I'm missing the connection between reregistration and report > > > > dispatching. > > > [EZ] Sorry for not being verbose. The need for Events dispatcher is > > > based on the fact that only one client should respond to Report with > > > ReportRepress. Reports are "unsolicited" MADs coming into the > device. In > > > umad the implementation prevents any "multiple" client registration > for > > > receiving any "unsolicited" MAD - only one class-agent needs to be > there > > > handling "unsolicited" messages. This is fine - but what it means is > > > that when two clients wants to be notified about events they should > > > register with that agent and the agent should be able to dispatch > the > > > message to all registered clients as well as send only one response > > > back. > > > > Wouldn't report represses be reference counted and only actually sent > on > > the wire when all subscribed clients within the node indicated repress > ? > [EZ] As you say there are many ways to skin a cat. I am not sure we need > to wait for all clients as they are located on the same node and will be > surely notified. Right, it just needs to be done once whether it was actually delivered to any client, clients, or none at all. -- Hal _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
