Re: [PATCH rdma-next v1 1/6] IB/uverbs: Allow CQ moderation with modify CQ

Jason Gunthorpe
2017-10-29T17:43:45Z

On Sun, Oct 29, 2017 at 03:51:35PM +0200, Leon Romanovsky wrote:
> From: Yonatan Cohen <yonatanc-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>
> Uverbs support in modify_cq for CQ moderation only.
> Gives ability to change cq_max_count and cq_period.
> CQ moderation enhance performance by moderating the number
> of cookies needed to create an event instead of application
> having to suffer from event per cookie.

Like the other recent uAPI patches, lets us see the rdma-core side and
man page first please..

Can you organize all of them into a rdma-core branch someplace?

Not really sure what a cookie is, or why this should be needed when we
already have the means to indicate if CQE's should be signalled or
not.

I guess it is for UD applications where the existing signalled stuff
isn't applicable?

> +int ib_uverbs_ex_modify_cq(struct ib_uverbs_file *file,
> + struct ib_device *ib_dev,
> + struct ib_udata *ucore,
> + struct ib_udata *uhw)

Is this really a good idea?

Why not ib_uverbs_set_cq_moderation ?

We don't have to keep making these thicker and thicker APIs if there
isn't a reason :(

Jason