[ofa-general] [PATCH 1 of 3] IB/verbs: add cq comp_vector support in core

[Michael S. Tsirkin]

> Quoting Hoang-Nam Nguyen <HNGUYEN at de.ibm.com>:
> Subject: Re: [ofa-general] [PATCH 1 of 3] IB/verbs: add cq comp_vector support in core
> 
> Hello Michael and Roland!
> How about a new verb delivering number of cqs associated with a
> comp_vector like this
> 
> /**
>  * Returns number of cqs assigned to comp_vector
>  * @return < 0 in error case eg invalid comp_vector
>  */
> int ib_query_comp_vector(struct ib_device *dev, int comp_vector);
> 
> A consumer or ULP would be able to pick an "empty" comp_vector.
> Surely that does not prevent that a certain comp_vector resp. IRQ
> can be "overloaded", and that's another topic.
> Thanks
> Nam
> PS: I'm waiting for your comments first, a patch will come later.

I'm not convinced it's an interesting metric.
A CQ which has multiple QPs assigned to it might get more traffic
than a CQ which only has a single QP.

My gut feeling would be that once ULPs learn to use multiple vectors,
each ULPs will spread across them evenly, without help from provider.

-- 
MST