FS#68031 - [openmpi] enable CUDA support

Attached to Project: Arch Linux
Opened by Jakub Klinkovský (lahwaacz) - Monday, 28 September 2020, 14:46 GMT
Last edited by Levente Polyak (anthraxx) - Sunday, 21 March 2021, 12:07 GMT
Task Type Feature Request
Category Packages: Extra
Status Closed
Assigned To Levente Polyak (anthraxx)
Architecture All
Severity Low
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 1
Private No

Details

Using GPU codes on HPC clusters or workstations often requires using so-called "CUDA-aware" MPI in order to avoid extra copies when working with data allocated on the GPU. In OpenMPI, the CUDA support can be enabled with "--with-cuda=/opt/cuda". See https://www-lb.open-mpi.org/faq/?category=buildcuda for details.

It would be nice to enable CUDA support in the Arch package. As far as I can tell, "cuda" can be added just to makedepends and optdepends, since OpenMPI has a dynamic plugin architecture and building the CUDA plugins should not affect the behaviour on systems where CUDA is not installed. Adding the --with-cuda flag leads to the compilation of these extra files:

usr/lib/openmpi/libmca_common_cuda.so
usr/lib/openmpi/libmca_common_cuda.so.40
usr/lib/openmpi/libmca_common_cuda.so.40.20.0
usr/lib/openmpi/openmpi/mca_btl_smcuda.so
usr/lib/openmpi/openmpi/mca_coll_cuda.so
usr/lib/openmpi/openmpi/mca_rcache_gpusm.so
usr/lib/openmpi/openmpi/mca_rcache_rgpusm.so
usr/share/openmpi/help-mpi-btl-smcuda.txt
usr/share/openmpi/help-mpi-coll-cuda.txt
usr/share/openmpi/help-mpi-common-cuda.txt
This task depends upon

Closed by  Levente Polyak (anthraxx)
Sunday, 21 March 2021, 12:07 GMT
Reason for closing:  Implemented
Additional comments about closing:  4.0.5-3
Comment by Jakub Klinkovský (lahwaacz) - Monday, 15 February 2021, 20:06 GMT
The OpenMPI NEWS file has this entry for version 1.7.3 (17 Oct 2013):

- Make CUDA-aware support dynamically load libcuda.so so CUDA-aware
MPI library can run on systems without CUDA software.

https://raw.githubusercontent.com/open-mpi/ompi/v4.0.x/NEWS
Comment by Sebastian Eberhardt (un533n) - Saturday, 20 March 2021, 21:30 GMT
There is a cuda-aware openmpi package in the AUR which will replace the default openmpi package if you need openmpi compiled with cuda support. https://aur.archlinux.org/packages/openmpi-cuda/
Comment by Jakub Klinkovský (lahwaacz) - Sunday, 21 March 2021, 08:28 GMT
@un533n: I'm aware of that, but the point of this request is to enable the support in the official package.

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