[ofa-general] mthca max_sge value... ugh.

[Jack Morgenstein]

On Monday 19 May 2008 08:54, Roland Dreier wrote:
> The mlx4 case is a simple example: send work requests support more s/g
> entries than receive work requests do.  So query HCA must return the
> lower receive work request limit, but I see no reason why create QP
> can't return the actual limit for send work requests.
> 
Then, we get into the complexity of sanity checking in create_qp (since we should
be able to use the value returned by create-qp when calling create-qp, and get
the same result). Essentially, we will need to check the requested sge numbers
per QP type, whether it is for send or receive, etc. IMHO, this gets nasty very
quickly -- creates a problem with support -- users will need a "roadmap" for create-qp.

I much prefer to treat the query_hca returned values as absolute maxima, and enforce
these limits (although this is at the expense of additional s/g entries for some
qp types and send/receive).

- Jack