[openib-general] [PATCH] [RFC] dapltest change for iwarp

[Sean Hefty]

Steve Wise wrote:
> The Chelsio RNIC has this issue.  If the server sends the first FPDU
> _before_ the client driver has moved the connection/qp into RDMA mode,
> then the data is placed as streaming data and the connection must be
> terminated (dapltest 6 exposes this intermittently).  Ammasso doesn't
> have this issue, but other RNIC's probably will.  
> 
> One thing I'm experimenting with is to delay the ESTABLISHED event on
> the server side until the first FPDU is received.  However, we still
> probably need a way for an application to know whether the client has to
> send first (or the server as you pointed out).
> 
> I believe rnic-pi has an attribute that indicated this behavior...

Can this be hidden from the user?  If the client side needs to send the first 
message, couldn't the connection protocol send a 0-byte message that the server 
strips out?  The ESTABLISHED event would be delayed until this message is received.

Also, wouldn't this issue need to be resolved based on both the local and remote 
device capabilities?  I.e. if the server is using an Ammasso RNIC, it needs to 
know the behavior of the remote RNIC, in case it's Chelsio.  Is this information 
carried as part of the connection, or does iWarp force the client to initiate 
the first send?

- Sean