[rds-devel] FW: RDS -- RDMA out of order

[Tang, Changqing]

Andy,
	I checked that the messages were retransmitted by me after the messages were dropped.
This comes to another question, if rds-rdma messages to the same target process are dropped, does RDS drop them in the same order as user posted ?

	What I noticed is that the dropped order is not the same as the order I posted, I want to check with you if this is the anticipated RDS behavior.  I prefer RDS to drop messages in the same order as they are posted, the reason for it is that, application does not need to check the order of dropped messages, application only needs to decide to retransmit it or not.

	Thanks.

--CQ


-----Original Message-----
From: Andy Grover [mailto:andy.grover at oracle.com] 
Sent: Friday, April 30, 2010 2:50 PM
To: Tang, Changqing
Cc: Tina Yang; RDS Devel
Subject: Re: [rds-devel] FW: RDS -- RDMA out of order

On 04/30/2010 08:56 AM, Tang, Changqing wrote:
> Andy, I post 3 rdma-write using control message, asking for
> notification when complete. However, I get the notification for the
> last post , so my code catches an out-of-order error,
>
> Does RDS keep the completion order and therefore notification order?

3 rdma-writes to the same remote node, or different ones?

RDS only guarantees ordering among messages to a single (host, port) tuple.

Regards -- Andy