[ofa-general] post_recv question

[Gleb Natapov]

On Thu, Feb 21, 2008 at 10:34:47AM -0600, Steve Wise wrote:
> To further complicate things, this race condition is never seen _if_ the  
> application uses the same QP to advertise (send a credit allowing the  
> peer to SEND) the RECV buffer availability.  So if the app posts a SEND  
> after the RECV is posted and that SEND allows the peer access to the  
> RECV buffer, then everything is ok.  This is due to the fact that the  
> FW/HW will process the SEND only after processing the RECV.  If the app  
> uses a different QP to post the SEND advertising the RECV, then the race  
> condition exists allowing the peer to SEND into that RECV buffer before  
> the HW makes it ready.
>
OpenMPI can be configured to send credit updates over different QP. I'll
try to stress it next week to see what happens.

--
			Gleb.