# CUDA aware MPI works on system but not for Julia

**URL:** <https://discourse.julialang.org/t/cuda-aware-mpi-works-on-system-but-not-for-julia/75060>\
**Category:** Julia at Scale\
**Tags:** parallel, mpi\
**Created:** [January 23, 2022, 9:39am UTC](https://discourse.julialang.org/t/cuda-aware-mpi-works-on-system-but-not-for-julia/75060 "2022-01-23T09:39:06Z")\
**Posts on this page:** 1\
**Showing post:** 4

<div class="post-metadata">

**Author:** ![samo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/samo/32/35398_2.png) [@samo](https://discourse.julialang.org/u/samo)\
**Post date:** [January 23, 2022, 10:43am UTC](https://discourse.julialang.org/t/cuda-aware-mpi-works-on-system-but-not-for-julia/75060/4 "2022-01-23T10:43:21Z")

</div>

```julia
JULIA_CUDA_USE_BINARY_BUILDER=false

```

needs to be set for each process. One way could be to put it in ~.bashrc or similar, another way to set it explicitly everywhere, i.e. the idea is:

```julia
mpiexec -n 2 'JULIA_CUDA_USE_BINARY_BUILDER=false julia alltoall_test.jl'

```

Maybe you will need to put `JULIA_CUDA_USE_BINARY_BUILDER=false julia alltoall_test.jl` in a shell script and call

```julia
mpiexec -n 2 my_julia_multi_gpu_app.sh

```

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