Re: [PATCH for-next] IB/cma: Introduce rdma_set_min_rnr_timer()

Jason Gunthorpe
2021-03-31T17:40:07Z

On Wed, Mar 31, 2021 at 05:38:26PM +0000, Haakon Bugge wrote:
>
>
> > On 31 Mar 2021, at 19:35, Jason Gunthorpe <jgg@nvidia.com> wrote:
> >
> > On Wed, Mar 31, 2021 at 05:09:27PM +0000, Parav Pandit wrote:
> >>
> >>
> >>> From: Haakon Bugge <haakon.bugge@oracle.com>
> >>> Sent: Wednesday, March 31, 2021 8:20 PM
> >>>
> >>>> On 31 Mar 2021, at 15:35, Jason Gunthorpe <jgg@nvidia.com> wrote:
> >>>>
> >>>> On Wed, Mar 31, 2021 at 01:34:06PM +0000, Haakon Bugge wrote:
> >>>>
> >>>>>> Actually I bet you could do this same thing entirely in userspace by
> >>>>>> adjusting rdma_init_qp_attr() to copy the data that would be stored
> >>>>>> in the cm_id.. ??
> >>>>>
> >>>>> This will definitely not solve the issue for kernel ULP, e.g., RDS.
> >>>>
> >>>> Sure, that makes sense to have some rdmacm api in-kernel only
> >>>
> >>> Let me send a v2 doing only that.
> >>>
> >>>>> Further, why do we have rdma_set_option() with option
> >>> RDMA_OPTION_ID_ACK_TIMEOUT ?
> >>>>
> >>>> It may have been a mistake to do it like that
> >>>
> >> Timeout value goes in the CM request message so setting it through
> >> the cm_id object was likely correct. This reflects into cm msg as
> >> well as in the QP of the cm_id.
> >
> > Ah, yes if it goes in the wire in a CM message it has to go to the
> > kernel.
>
> But does it go on the wire? No. The RNR Retry timer is not part of
> the negotiation with the peer.

I think Parav was talking about the ID_ACK_TIMEOUT

Jason