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From: Brian Barrett (brbarret_at_[hidden])
Date: 2005-08-09 09:04:52


On Aug 9, 2005, at 8:48 AM, Sridhar Chirravuri wrote:

> Does r6774 has lot of changes that are related to 3rd generation
> point-to-point? I am trying to run some benchmark tests (ex:
> pallas) with Open MPI stack and just want to compare the
> performance figures with MVAPICH 095 and MVAPICH 092.
>
> In order to use 3rd generation p2p communication, I have added the
> following line in the /openmpi/etc/openmpi-mca-params.conf
>
> pml=ob1
>
> I also exported (as double check) OMPI_MCA_pml=ob1.
>
> Then, I have tried running on the same machine. My machine has got
> 2 processors.
>
> Mpirun -np 2 ./PMB-MPI1
>
> I still see the following lines
>
> Request for 0 bytes (coll_basic_reduce_scatter.c, 79)
> Request for 0 bytes (coll_basic_reduce.c, 193)
> Request for 0 bytes (coll_basic_reduce_scatter.c, 79)
> Request for 0 bytes (coll_basic_reduce.c, 193)

These errors are coming from the collective routines, not the PML/BTL
layers. It looks like the reduction codes are trying to call malloc
(0), which doesn't work so well. We'll take a look as soon as we
can. In the mean time, can you just not run the tests that call the
reduction collectives?

Brian

-- 
   Brian Barrett
   Open MPI developer
   http://www.open-mpi.org/