[ofa-general] Questions about IPOIB handle last WQE event

[Shirley Ma]

On Wed, 2008-07-23 at 14:27 -0700, Roland Dreier wrote:
> > What's in my mind was to use a common approach for both nonSRQ and SRQ.
>  > Because nonSRQ doesn't have last WQE, but we could do post_send last WR
>  > when receiving DREQ to handle QP resource destroy for both nonSRQ and
>  > SRQ without setting QP to error status.
> 
> It would be nice if we could make the SRQ and non-SRQ code paths more
> similar and shrink the code.  But I'm not sure there's any reason to
> post a send work request in the non-SRQ case -- we can just destroy the
> QP after the last pending receive completes (but we have to wait for
> them all to complete before destroying the QP).

The reason is non-SRQ shares completion queue just as SRQ. Without post
a send work request, we don't know when the QP's last pending recieve
completes in the shared completion queue. We might be able to get it but
it would induce performance penalty. 

Thanks
Shirley