[openib-general] IB MTU tunable for uDAPL and/or Intel MPI?

[Arlin Davis]

Scott Weitzenkamp (sweitzen) wrote:

>This didn't help.  Osu_bibw.c still reports max bi bandwidth in the
>1600s, should be in the 1900s.  I looked back at my notes, and OFED 1.0
>rc4 had desired max bi bandwidth with OFED 1.0 rc4, did the uDAPL IB MTU
>change?
>  
>
uDAPL does not have any control over IB MTU using OpenIB-cma. We just 
use the path record that
is supplied from Open SM. Not sure where or when the change occured but 
it is not in uDAPL.

>$ mpiexec -genv I_MPI_DAPL_PROVIDER OpenIB-scm -genv I_MPI_DEBUG 3 -genv
>I_MPI_DEVICE rdssm -genv LD_LIBRARY_PATH .../lib -n 2 ../osu_bibw.x
>I_MPI: [0] set_up_devices(): will use device: libmpi.rdssm.so
>I_MPI: [0] set_up_devices(): will use DAPL provider: OpenIB-cma
>I_MPI: [0] set_up_devices(): will use device: libmpi.rdssm.so
>I_MPI: [0] set_up_devices(): will use DAPL provider: OpenIB-cma
>  
>
It picked up the OpenIB-cma device instead of OpenIB-scm.

-arlin