[ofa-general] [PATCH 13/16 v2] IB/ipoib: Add support for modify CQ

[Eli Cohen]

On Mon, Jan 28, 2008 at 11:14:41AM -0800, Ralph Campbell wrote:
> Can you send out a specification for what ib_modify_cq()
> is supposed to do?  It isn't part of the IBTA verbs spec.
> so I don't know how other HCAs are supposed to implement it.
> 

Many NICs provide for controlling the rate of generation of interrupts.
Controlling the rate of interrupt generation helps reducing the overhead
of interrupt handling.
In IB, a CQ may generate notifications which are asynchronous from the
software perspective and may generate interrupts. The following
interface allows to control this function on the devices which support
this. A notification will be generated if any of two conditions become
true.

1. cq_count - number of CQEs were pushed into the CQ since the last
notificaton.
2. cq_period - number of micorseconds elapsed since the last
notification.

After the generation of a notification the coditions are reset.

> > + * ib_modify_cq - Modifies moderation params of the CQ
> > + * @cq: The CQ to modify.
> > + * @cq_count: number of CQEs that will trigger an event
> > + * @cq_period: max period of time in usec before triggering an event
> > + *
> > + */
> > +int ib_modify_cq(struct ib_cq *cq, u16 cq_count, u16 cq_period);
> > +
>