[ofa-general] Re: [RFC] Receive Core Afinnity (aka RSS) support

[Roland Dreier]

 >  /**
 > + * ib_create_qp_range - Creates a range of QPs associated with the
 > + * specified protection domain.
 > + * @pd: The protection domain associated with the QP.
 > + * @qp_init_attr: A list of initial attributes required to create the
 > + *   QPs.  If QP creation succeeds, then the attributes are updated to
 > + *   the actual capabilities of the created QP.
 > + * @nqps: The number of required QPs
 > + * @align: Required alignment for the allocated QP numbers.
 > + * @list: pointer to an array to hold allocated QPs
 > + */
 > +int ib_create_qp_range(struct ib_pd *pd, struct ib_qp_init_attr *qp_init_attr,
 > +		       int nqps, int align, struct ib_qp *list[]);

Well, RSS for IPoIB is OK in theory but I think we really are getting to
the point of adding a lot of extra complexity to the RDMA core where
IPoIB is the only user.  And this new interface for a QP range seems
like the wrong level of abstraction -- it is exposing the mlx4
implementation details of RSS.  If the next HCA that comes out has a
different RSS scheme then we end up having to change all this.

So the details of how RSS works should be in low-level driver code.

By the way, Michael Chan from Broadcom just posted multi-rx-ring support
for bnx2 to netdev.

 - R.