[openib-general] openMPI for 2.6.17.10 kernel

[Jeff Squyres]

On Nov 30, 2006, at 2:58 PM, Steve Wise wrote:

>> 	// initiatior
>> 	ibv_create_qp(...);
>> 	ibv_modify_qp(...);// set pkey, port num, etc.
>> 	send_via_oob_channel(lid, mtu, my_port_num, ...other info...);
>> 	wait_for_oob_reply(...);
>> 	ibv_modify_qp(...);//set mtu, lid, remote_port #, etc.
>>
>> Are you telling me that the *ONLY* way to make QPs over iWARP
>> connections is to use the RDMA CM, and it is not possible to work
>> using a scheme like i listed above (passing relevant info via OOB
>> channels)?
>
> Yup.

Then why did Tom Tucker tell me otherwise last week?  Hrm.  Tom --  
did I not explain our current scheme well last week?

>> If so, I'm curious: what magic is the RDMA CM doing such
>> that this is necessary?
>
> Setting up an TCP connection and negotiating RDMA mode.

Are you telling me that ibv_create_qp() and ibv_modify_qp() don't  
actually make a connection?

Don't get me wrong -- we're moving towards the RDMA CM for OMPI, but  
I just want to understand what the problem is today, especially since  
I got seemingly opposite information last week.

-- 
Jeff Squyres
Server Virtualization Business Unit
Cisco Systems