[openib-general] IBV_WC_LOC_LEN_ERR in ibv_pingpong for message < 4KB

[Sayantan Sur]

Roland Dreier wrote:
>     Sayantan> Hi, If I run `ibv_pingpong' with msg size argument <
>     Sayantan> 4096, I am encountering a IBV_WC_LOC_LEN_ERR. I have
>     Sayantan> pasted the output from my run. Is this usage correct? Is
>     Sayantan> anybody else getting the same error too?
> 
> Are you passing the --size argument to both the client and server
> ibv_pingpong programs?  If not, then one side will post a receive
> buffer too small to receive the message that the other side sends, and
> you will get a local length error.

Thanks for your reply. Yes, I was assuming a `perf_main' style of usage, 
where it isn't necessary to pass the size information to the receiver 
command line.

> 
>     Sayantan> If I may ask, what do the messages like:
> 
>     Sayantan>   [ 0] 00860404
> 
>     Sayantan> mean? They are not coming from `ibv_pingpong' but from
>     Sayantan> somewhere else.  Are they supposed to be debug messages? 
>     Sayantan> If yes, how can I interpret them?
> 
> That's temporary debugging code from libmthca, specifically the CQ
> polling code.  It's dumping out the 32 byte CQ entry written by the
> HCA hardware.  You will need Mellanox documentation to interpret it
> (or you can just read the code in libmthca/src/cq.c).

Okay. I'll look at that file.

Thanks,
Sayantan.

> 
>  - R.


-- 
---------------------------------------------------------
Sayantan Sur            Graduate Research Assistant

395 Dreese Labs,        Computer Science and Engineering
Ohio State University,  Office : 774, Dreese Labs
Columbus,               email  : surs at cse.ohio-state.edu
Ohio - 43210.           phone(res) : 614.688.9792
USA.                    phone(off) : 614.292.8501
---------------------------------------------------------