[ofa-general] Re: setting iWarp IRD and ORD

[Steve Wise]

Kanevsky, Arkady wrote:
> And what happens when RNIC on two sides have a different upper limits?
> Specifically, if requestor asks for ORD which is bigger than responder 
> can handle?
> Is it user responsibility to pass ORD request out of bound to responder and
> if responder can not satisfy it then reject the request?
> Thanks,
>  

Yes.

> 
> Arkady Kanevsky                       email: arkady at netapp.com 
> <mailto:arkady at netapp.com>
> 
> Network Appliance Inc.               phone: 781-768-5395
> 
> 1601 Trapelo Rd. - Suite 16.        Fax: 781-895-1195
> 
> Waltham, MA 02451                   central phone: 781-768-5300
> 
>  
> 
>     ------------------------------------------------------------------------
>     *From:* Steve Wise [mailto:swise at opengridcomputing.com]
>     *Sent:* Thursday, January 03, 2008 9:42 PM
>     *To:* Sean Hefty
>     *Cc:* OpenFabrics General
>     *Subject:* [ofa-general] Re: setting iWarp IRD and ORD
> 
> 
> 
>     Sean Hefty wrote:
>>>     What exactly are you fixing?
>>>         
>>
>>     It may help to look at the patch for the librdmacm that I just posted.  The
>>     problem that was seen was that uDAPL set IRD/ORD to 16 in the connection
>>     request, but the passive side could only support 4.  The rdma_cm was supposed to
>>     use the lower value (provided by the user when calling rdma_accept) when
>>     transitioning the QP, but instead used the value from the request.
>>
>>     Since iWarp connect request doesn't carry the IRD/ORD and always uses the value
>>     provided by the user through rdma_connect or rdma_accept, it doesn't sound like
>>     it would hit this problem.  I just don't quite follow why
>>     iwcm_init_qp_rts_attr() doesn't set the QP attribute mask for IRD/ORD, or how
>>     the QP is programmed with these values.
>>
>>       
>     Perhaps this is a bug.  But the chelsio driver just saves off the
>     ord/ird from the connection parameters and then programs the qp with
>     these values when the qp is associated with the connection (just
>     after the connection goes into rdma mode)...
> 
>>     - Sean
>>       
> 
>