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Subject: [OMPI users] How "CUDA Init prior to MPI_Init" co-exists with unique GPU for each MPI process?
From: Dmitry N. Mikushin (maemarcus_at_[hidden])
Date: 2011-12-14 10:39:56


Dear colleagues,

For GPU Winter School powered by Moscow State University cluster
"Lomonosov", the OpenMPI 1.7 was built to test and popularize CUDA
capabilities of MPI. There is one strange warning I cannot understand:
OpenMPI runtime suggests to initialize CUDA prior to MPI_Init. Sorry,
but how could it be? I thought processes are spawned during MPI_Init,
and such context will be created on the very first root process. Why
do we need existing CUDA context before MPI_Init? I think there was no
such error in previous versions.

Thanks,
- D.