[dat-discussions] [openib-general] [RFC] DAT 2.0 immediate dataproposal

[Caitlin Bestler]

dat-discussions at yahoogroups.com wrote:
> Arkady,
> 
> Your requirements are slightly different then the proposed set of
> requirements. 
> 
> "iii) DAPL Provider does not provide any identification that
> that the Receive operation matches remote RDMA Write with
> Immediate data if it completes as Receive DTO.
> 
> 	- It is up to an ULP to separate Receive completion of remote
> Send from remote RDMA Write with 	  Immediate Data."
> 
> Tell me how this is possible? How can the application
> distinguish between a 4 byte message and a 4 byte immediate
> data message? We would have to add a new requirement... "If
> the provider supports immediate data in the payload the ULP
> cannot send a message equal to the immediate
> data size".
> 

The data sink knows whether the 4 bytes was sent as a message
or as an immediate because it is clear in the ULP context.
Possible methods:
	The expected completion is an immediate.
	All 4 byte messages are immediates.
	All 4 byte messages where the ms-byte is X are immediate.
	If its Tuesday its an immediate.
	If it's a prime number its an immediate
	...

But there is no clue from the transport layer.