UCX Memory mismatch in ompi_coll_base_gather_intra_binomial

[DreamerLuu]

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Background information

What version of Open MPI are you using? (e.g., v4.1.6, v5.0.1, git branch name and hash, etc.)

I am currently running the OpenMPI gather operation, which uses the ompi_coll_base_gather_intra_binomial algorithm for 8 GPUs. This function allocates host memory via malloc, but UCX employs the rendezvous protocol. When using IPCL, the runtime can only accept device pointers, leading to an error

Describe how Open MPI was installed (e.g., from a source/distribution tarball, from a git clone, from an operating system distribution package, etc.)

If you are building/installing from a git clone, please copy-n-paste the output from git submodule status.

Please describe the system on which you are running

• Operating system/version:
• Computer hardware:
• Network type:

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Details of the problem

Please describe, in detail, the problem that you are having, including the behavior you expect to see, the actual behavior that you are seeing, steps to reproduce the problem, etc. It is most helpful if you can attach a small program that a developer can use to reproduce your problem.

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shell$ mpirun -n 2 ./hello_world

[DreamerLuu]

May I ask if it's just that the algorithm of 'gather' is not compatible with UCX? Other communication primitives also have malloc host memory, but this situation has not occurred