[dat-discussions] [openib-general] [RFC]DAT2.0immediatedataproposal

[Larsen, Roy K]

>Roy,
>and if tomorrow iWARP decides to support Immediate data with variable
>length. API does not changes. Semantic does not changes and IB
>will not be able to support it.
>
>I am trying to define the semantic and API which will not have to be
>modified for each rev of the transport.

Arkady,

Simply define the API as all the parameters needed to do an RDMA write
followed by a send.  This is semantically all that many seem to believe
is required.  I would not restrict the size or contents of the send
buffer supplied by the ULP.  Could even be a zero length buffer just to
trigger the receive completion.  Don't try to make the operation any
more magical than that.  All transports can implement it consistently
and the ULP can handle it consistently too. I can't see how anyone could
object to that API since it is providing the service desired
consistently among all transports.

That said, I am not conceding that this service is the equivalent to IB
RDMA write with immediate data and want to see a general extension API
added for this and any future transport service that won't be supported
by the DAPL API. 

Roy

>
>Arkady Kanevsky                       email: arkady at netapp.com
>Network Appliance Inc.               phone: 781-768-5395
>1601 Trapelo Rd. - Suite 16.        Fax: 781-895-1195
>Waltham, MA 02451                   central phone: 781-768-5300
>