[openib-general] RNR_RETRY_EXC_ERR and completion opcode in "send_lat"

[Dotan Barak]

Hi Sayantan.
Sayantan Sur wrote:

>Hi,
>
>I have a question about the "status" field for a completion which is due
>to RNR retry exceeded error. I trivially modified the `send_lat' program
>(from the Gen2 perftest directory) to use SRQ and not post receives
>after some specified time. Given the "rnr_retry" attribute of the QP not
>to be 7 (infinite retry), I'm expecting the sender to get an erroneous
>completion with IBV_WC_RNR_RETRY_EXC_ERR.
>
>So far so good ... however, the completion I pull out of the send_cq,
>lists the opcode of the completion to be IBV_WC_RECV! Is this expected?
>
>I am using OFED 1.1 on dual Intel Xeon machines with Mellanox DDR HCAs
>(two ports) and in MemFree mode. The distribution used is RH AS4 (Nahant
>Update 3), with kernel version 2.6.17.7.
>
>If someone could explain this behavior, or suggest a workaround, it'd be
>great.
>
>TIA,
>Sayantan.
>  
>
I toke the following text from the man pages that i wrote to the libibverbs:
"Not all wc attributes are always valid. If the  completion  status  is
       other  than  IBV_WC_SUCCESS,  only the following attributes are 
valid:
       wr_id, status, qp_num, and vendor_err."

In other words, the opcode is not valid if you have a completion with error.

Thanks
Dotan