[mvapich-discuss] MPI blocking mode progress with 10GbE/ iWARP

[Sundeep Narravula]

> I would like to run mvapich2 in blocking mode (i.e., do not take up any
> CPU while waiting for incoming messages).  I would like this even when I
> am running one MPI process per node. What are the prerequisites to
> achieve this using the current Gen2-iWARP transport? Should I simply use
> the MV2_USE_BLOCKING parameter (knowing that it is documented to only
> work for the Gen2-InfiniBand transport)? Or do I need to take into
> account additional parameters such as the threading support parameter to
> the mvapich2 library build?
>
Hi Ken,

  Currently if you run one MPI process per node you *can* use
MV2_USE_BLOCKING mode with MV2_USE_IWARP_MODE with the Gen2-iWARP device.
You should not need to worry about other issues for this case. The
following execution is a perfectly valid one.

mpiexec -n 2 -env MV2_USE_IWARP_MODE 1 -env MV2_USE_BLOCKING 1 ./a.out

Please note that as of now this works only for one MPI process per node.

Hope that helps.

Regards,
  --Sundeep.