[openib-general] Immediate data question

[Tang, Changqing]

Roland:
	This is a followup question. If one process uses
IBV_WR_SEND_WITH_IMM  and IBV_SEND_INLINE to send 8 bytes, but the
receiver process does not post the corresponding receive to the QP,
instead,  this receiver process and other processes are doing  heavy
RDMA_WRITE/READ traffic each other.

	Does this pending SEND_WITH_IMM message affect the performance
of the receiver process ? Is this message buffered in the receiver's
HCA, or the sender retry and get RNR ack until receiver posts a receive
?

	Thanks.

--CQ


> -----Original Message-----
> From: Roland Dreier [mailto:rdreier at cisco.com] 
> Sent: Monday, February 05, 2007 5:03 PM
> To: Tang, Changqing
> Cc: Michael S. Tsirkin; openib-general at openib.org
> Subject: Re: Immediate data question
> 
>     Changqing> Thank you. Other than using immediate data to send
>     Changqing> notification from one end to the other of a QP, is
>     Changqing> there any other way to do this ? For example, can I
>     Changqing> modify QP state from RTS to other state on one end, and
>     Changqing> then the other end gets some notification when I query
>     Changqing> the QP ?
> 
> Not that I know of.  You would need to do something that 
> triggers something to be sent on the wire, and I don't know 
> of any way to do that other than posting a work request.
> 
>  - R.
>