[Mpi-22] [Mpi-forum] MPI 2.2 proposal: resolving MPI_Request_free issues

[Jeff Squyres]

On Jul 15, 2008, at 6:11 AM, Hubert Ritzdorf wrote:

> Freeing user buffers which are still in use by an interconnect is  
> another topic. What's about the receive buffer ? The receive buffer  
> could also already be freed or re-used in another way directly after  
> the receive was finished.

That should be fine.

> Does the retransmit to the receive buffer not cause corresponding  
> problems ?

I would think that the hardware should recognize it as a duplicate  
message and drop it (therefore not causing a problem with the receive  
buffer).  After all, in my example, only the receiver's ACK was lost  
-- the message was otherwise already successfully received.

> I think that the receive cannot return before the transfer is  
> finished and the user buffers can be reused.

Agreed.


-- 
Jeff Squyres
Cisco Systems