[openib-general] Re: RMPP

[Sean Hefty]

Hal Rosenstock wrote:
>>>In one test case, I see the first RMPP DATA segment sent and there is no
>>>response (ACK) from the receiver (this was due to a (receiver) test
>>>program issue). The transmitter retry depends on retries in the send_wr
>>>ud structure. Does it need to known/Is there a way to know that this
>>>failed (no ACK, etc.) when retries are exhausted or is this reliant on
>>>the receiver rerequesting or is the entire RMPP transaction treated like
>>>a UD send (e.g. unreliable) ?
>>
>>The RMPP send is treated as reliable, even if no response is expected.  If 
>>the send is not ACKed completely, the request will timeout, and a send 
>>failure is reported to the user.  If the send completes successfully, then 
>>the user knows that it was received by the remote side; although, there's no 
>>guarantee that it was processed by anyone.
> 
> 
> Is this on any (RMPP) transmits or just requests ? I will check to see
> if I can see this.

This is true for any RMPP send operation.

You can test for this by running a grmpp client, without having the grmpp 
server loaded on the destination node.  You should see a timeout error 
sending the MAD in the messages log file.

You can also see timeouts on both requests and replies if you run grmpp and 
increase the number of messages to a few thousand.

(e.g. insmod ib_grmpp.ko "slid=1" "dlid=2" "message_count=15000" 
"message_size=100" "responses=1")

- Sean