If it is up to the ULP to separate out "normal" receive data from that associated with a write immediate, how is this different from the ULP doing a write followed by a send? If there is no difference, then what we're really talking about is a convenience to the initiating ULP.
Perhaps what would be best is to construct an API that allows the ULP to perform standard write/send operations into one call which the underlying provider could optimize into one transaction with the associated interconnect interface. Better yet, a general request combining interface would have even more value, but calling this write/send "immediate" data is a stretch, if not downright silly. Some transports have true immediate data that provides unique value. There is nothing unique in a write/send sequence - ULPs do it all the time... Roy -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Caitlin Bestler Sent: Monday, February 06, 2006 10:48 AM To: [EMAIL PROTECTED]; Kanevsky, Arkady; Sean Hefty Cc: [email protected] Subject: RE: [dat-discussions] [openib-general] [RFC] DAT 2.0 immediatedataproposal [EMAIL PROTECTED] 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. _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
