[openib-general] openIB gen2 user space verbs API

[Or Gerlitz]

Roland>Which applications are using these operations as you describe?

Ignoring APM, one can claim that using query qp to get the qp state is
means of debugging and not
needed for an app regular flow. Correct, we are using it in our dapl
code when modify qp fails
and i know an HPC app using it in its startup code in the same manner.

Taking APM into account, as the QP REARMED to ARMED state transition is
done by the HCA HW 
when data is delivered over the RC connection, there are apps that do qp
query to sense this transition
and modify the qp mig state to MIGRATED.

Other than debugging and APM one can implement resource tracking code
that can query a specific
qp per request, or qp caching scheme that keeps created/init-ed or even
connected QPs and before/after
handing them to consumers queries the QP for verifyig the state. Some of
the gen1 stacks have resource
tracking as i describe here, also there are apps doing this caching i
mentioned.

For getting the inline size (which you indeed propose to return its max
size from the qp create func)
every app which wishes to use inline (eg MVAPICH) would query the qp
state.

To me query qp and hca capabilities seems as a must, the other queries
(CQ MR etc) are less important.

Or.
-----Original Message-----
From: openib-general-bounces at openib.org
[mailto:openib-general-bounces at openib.org] On Behalf Of Roland Dreier
Sent: Monday, April 18, 2005 7:28 PM
To: Or Gerlitz
Cc: openib-general at openib.org
Subject: Re: [openib-general] openIB gen2 user space verbs API

    Or> Other than getting the max inline size, query qp is used to
    Or> get the current QP state, examples are app error flow (eg when
    Or> modify qp failed) and app APM flow to sense some of the state
    Or> transitions done by the HW. These are only examples I quickly
    Or> thought of, I guess there are more.

Which applications are using these operations as you describe?

 - R.
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