What are those mechanisms that MPI and SHMEM use?

Wouldn't it be useful if the requester could simply use REMOTE_CQ_DATA and be 
assured that the responder wouldn't get the completion until the data had been 
placed into cache?
-Paul

-----Original Message-----
From: Sur, Sayantan [mailto:[email protected]] 
Sent: Wednesday, October 21, 2015 9:50 AM
To: Paul Grun; [email protected]
Subject: Re: [ofiwg] A question on FI_DELIVERY_COMPLETE

Having the notification at the requester is useful for MPI RMA or SHMEM use 
cases. This allows MPI/SHMEM to wait for a local event that indicates remote 
completion. The responder side is passive in these use cases.

Both MPI and SHMEM have different mechanisms to let the responder know when it 
is able to look at the data.

Thanks,
Sayantan.

From: 
<[email protected]<mailto:[email protected]>>
 on behalf of Paul Grun <[email protected]<mailto:[email protected]>>
Date: Wednesday, October 21, 2015 at 9:33 AM
To: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Subject: [ofiwg] A question on FI_DELIVERY_COMPLETE

Here’s my understanding of how FI_DELIVERY_COMPLETE works on the *responder* 
end:  If you are doing an RMA operation, and the requester uses CQ_REMOTE_DATA 
to signal the end of the transfer to the responder, and the responder has 
FI_DELIVERY_COMPLETE set, then the responder won’t get a completion event until 
the data is actually visible to the responder.

I ask because the man pages imply that FI_DELIVERY_COMPLETE, which is an 
operation flag, applies only to the requester side.  But it is much less 
important to notify the requester that data is visible to the responder, than 
it is to notify the responder itself.

Comments?
-Paul


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