# MPI error for compiled bundle

**URL:** https://discourse.julialang.org/t/mpi-error-for-compiled-bundle/113380
**Category:** General Usage
**Created:** [April 23, 2024, 8:53am UTC](https://discourse.julialang.org/t/mpi-error-for-compiled-bundle/113380 "2024-04-23T08:53:42Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![jsjie](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jsjie/32/22477_2.png) [@jsjie](https://discourse.julialang.org/u/jsjie)
#### Post date: [April 23, 2024, 8:53am UTC](https://discourse.julialang.org/t/mpi-error-for-compiled-bundle/113380/1 "2024-04-23T08:53:43Z")

</div>

Because I use `MPI.jl` in my code, the compiled bundle will contain MPI in it, and I’ve always been using that MPI for consistence. However, recently this MPI fails. After some digging, I think the problem is in the 4.2.0+0 build of `MPICH_jll`.  
It is very easy to find this issue, if you have several artifact versions in your computer.

`~/.julia/artifacts/69656c7b06da50dba7bdeef69f0ac06e478ac05a/bin/mpirun -h` works well, which corresponds to v4.1.2+0 build.  
`~/.julia/artifacts/0ed4137b58af5c5e3797cb0c400e60ed7c308bae/bin/mpirun -h` works well, which corresponds to v4.1.2+1 build.  
But, `~/.julia/artifacts/cacaf4d3b5c79a7723468fc6b854afba34839634/bin/mpirun -h` cannot work, the error message is:  
`error while loading shared libraries: libhwloc.so.15: cannot open shared object file: No such file or directory`

The reason, I believe, is that `hwloc` is used statically in previous versions, but dynamically in the new v4.2.0+0 build. There are two proofs:

1. the size of `mpiexec.hydra` (and some other binaries related to hydra) does not differ much in v4.1.2+0 and v4.1.2+1, but is much smaller in v4.2.0+0. I believe old versions contain the static library of hwloc within them, which makes the difference.
2. the v4.2.0+0 version introduces the dependency on `Hwloc_jll`

The problem is, the artifacts system only works within Julia, and MPI is not a part of Julia. `mpiexec.hydra`, even the one inside `~/.julia/artifacts`, surely won’t search the julia artifact path for shared objects it needs, unless we change the `LD_LIBRARY_PATH`, which is inconvenient, especially when you are creating portable binaries.

It should be mentioned that, in [the documentation of openmpi](https://docs.open-mpi.org/en/v5.0.x/installing-open-mpi/required-support-libraries.html), it is warned that

“Regardless, _it is critically important_ that if an MPI application — or any of its dependencies — uses Hwloc, it uses the _same_ Hwloc with which Open MPI was compiled.”

So I cannot see the reason why hwloc is changed from static linking to dynamic linking. Any ideas?