[ewg] APM Example

[Roland Dreier]

    Abhinav> However, VAPI has an event which specifies the successful
    Abhinav> transition of MIGRATED -> ARMED (I know very well, that
    Abhinav> it is done through modify_qp). But just the success of
    Abhinav> modify_qp does not explicitly tell the time at which the
    Abhinav> transition successfully occured, does it?

You don't know the time that the transition occurred, except that it
is between when you called modify QP and when it returned.  But an
asynchronous event doesn't really help, does it?  All an event would
tell you is that the transition occurred some time before the event was
generated, which is some time before when the event was delivered to you.

    Abhinav> Specifically:

    Abhinav> VAPI_PATH_MIG_ARMED would make my day. I believe that
    Abhinav> VAPI_QP_PATH_MIGRATED is similar to
    Abhinav> IB_EVENT_PATH_MIG. Please correct me if i am wrong.

I see... VAPI_PATH_MIG_ARMED is a new event that was added only in
VAPI 4.1.0, which was why I didn't know about it.  Only Mellanox HCAs
support it, it is not specified by the InfiniBand architecture, and I
don't really see the point of it (as I tried to explain above).

 - R.