[openib-general] Re: OpenIB documentation

[Roland Dreier]

    Christopher> Creating a thread is no problem. I notice that the
    Christopher> queue data structures have pthread mutex locks and
    Christopher> condition variables predefined; what is this for? 
    Christopher> Could I simply use pthread's synchronization
    Christopher> primitives against these constructs? If so, are they
    Christopher> already initialized during queue creation, or will I
    Christopher> have to do that manually?

The verbs functions are completely thread-safe.  The internal pthread
spinlocks and mutexes are hidden from the consumer, but no additional
synchronization is needed around any ibv_ calls.

    Christopher> Getting back to ibv_get_cq_event(), what is it then
    Christopher> that triggers a completion event?

When a completion entry arrives in a CQ that has been armed with
ibv_req_notify_cq().

    Christopher> And finally, with regard to ibv_req_notify_cq(), just
    Christopher> what does the second parameter mean? The example
    Christopher> programme passes a 0 value for solicited_only; this
    Christopher> is in a section that is relying on events. I'm
    Christopher> totally confused by what is meant regarding "only
    Christopher> solicited for notification."

solicited_only==0 means that any completion entry triggers an event;
solicited_only!=0 means that only solicited entries trigger an event.
See the verbs spec for the precise definition of which completions are
considered solicited.

 - R.