[bug#27850] gnu: mpi: openmpi: Don't enable thread-multiple

[Dave Love <fx@gnu.org>]

Ludovic Courtès <ludovic.courtes@inria.fr> writes:

> Dave Love <fx@gnu.org> skribis:
>
>> Ludovic Courtès <ludovic.courtes@inria.fr> writes:
>
> [...]
>
>>>>      (arguments
>>>>       `(#:configure-flags `("--enable-static"
>>>>  
>>>> -                           "--enable-mpi-thread-multiple"
>>>
>>> Should we upgrade our openmpi package instead of doing this?
>>
>> I don't know whether they've fixed all the breakage I knew about in
>> OMPI 2 or whether there's still any penalty from thread-multiple.  1.10
>> seems fairly safe, but I don't have strong opinions if people think 2 is
>> solid.  Apart from ABI incompatibility, I assume it has the usual
>> incompatibilities at the mpirun/MCA level, and that they aren't well
>> documented.
>
> ABI compatibility is normally not an issue with Guix, so I’d be in favor
> of upgrading to 2.0.3.  Would you like to do it?

Maybe, but what about the non-ABI compatibility I expect there is?  (I
don't know whether there's still any penalty from thread-multiple
anyhow; I guess not, as I see it's not the default.)  2.1 probably also
needs non-trivial work in figuring out whether it still needs a bundled
libevent, for instance.

If anyone's using it seriously, I'd have thought effort would be better
spent on support for SLURM (as it's in Guix) and supporting
high-performance fabrics (which I started on).