Re: [OMPI packagers] Possible to have multiple OpenMPIs simultaneously?

2020-11-29 Thread Aisha Tammy via ompi-packagers
On 11/29/20 9:39 PM, Gilles Gouaillardet wrote:
> I made a quick check, and the latest 3.1 MPI standard is supported (at least) 
> from Open MPI 2.0.*
>
> (you can check the MPI_VERSION and MPI_SUBVERSION macros in 
> ompi/include/mpi.h[.in])
Amazing!

Thanks a lot!
Aisha
>
>
> please do note that the 2.0 and 2.1 series are no more supported.
>
>
> Cheers,
>
>
> Gilles
>
>
>
> On 11/30/2020 11:27 AM, Aisha Tammy via ompi-packagers wrote:
>> On 11/29/20 7:45 PM, Gilles Gouaillardet wrote:
>>> Aisha,
>>>
>>> yes, you can install multiple Open MPI implementations in parallel,
>>> simply use a different prefix when running configure.
>>>
>>> Newer versions of Open MPI support the latest MPI standard
>> Makes sense :D
>>> (there is
>>> not a direct link between an Open MPI version
>>> and the MPI standard version though).
>> Do all OpenMPI major versions support the latest standard?
>> That would simplify things a lot :D
>>> That being said, with the exception of a few removed/deprecated
>>> subroutines, a given version of the MPI standard is a superset of the
>>> previous versions.
>>> This is at the source level, and Open MPI does not generally guarantee
>>> ABI compatibility between two major versions.
>> Makes sense too. I was not expecting ABI compatibility between major 
>> versions.
>>> Last but not least, keep in mind several packages depend on MPI, for
>>> example mpi4py (python bindings), parallel FFTW (Fast Fourier
>>> Transformations), parallel hdf5/netcdf (I/O).
>>> So since Open MPI has generally no ABI compatibility between major
>>> versions, you would also need multiple versions of the dependents
>>> packages (one per Open MPI version).
>> Yes, I am aware that we would need multiple "slots" for each dependent
>> packages. We have a half finished project that was started a couple
>> of years ago which does this slotting of packages and MPI implementations.
>>
>> Thanks a lot for the answers.
>>
>> The unfortunate reality is that the default MPI pakages are badly managed in 
>> almost
>> all operating systems and any decent cluster has a sysadmin who cooks
>> up a solution for their use case :(
>> Even users who want to use OpenMPI, most of the times, install it manually to
>> tune and get a better control over it.
>>
>> Making the default packages saner at the operating system level should 
>> hopefully
>> help a lot of people.
>>
>> Best,
>> Aisha
>>
>>> Cheers,
>>>
>>> Gilles
>>>
>>> On Mon, Nov 30, 2020 at 6:00 AM Aisha Tammy via ompi-packagers
>>>   wrote:
>>>>   Hi,
>>>>    I am a package manager for Gentoo Linux and we are currently trying
>>>> to get better MPI support for our package tree.
>>>>
>>>> A curious question was whether it was possible to have multiple OpenMPI
>>>> implementations installed in parallel?
>>>> There seem to be multiple OpenMPI versions being supported and presumably
>>>> they are supporting different standards of MPI - 2, 3, 3.1 ?
>>>>
>>>> Am I correct in making this assumption?
>>>> If so, it should be possible to allow multiple OpenMPI versions together.
>>>>
>>>> Thanks a lot,
>>>> Aisha
>>>>
>>>> ___
>>>> ompi-packagers mailing list
>>>> ompi-packagers@lists.open-mpi.org
>>>> https://rfd.newmexicoconsortium.org/mailman/listinfo/ompi-packagers
>>> ___
>>> ompi-packagers mailing list
>>> ompi-packagers@lists.open-mpi.org
>>> https://rfd.newmexicoconsortium.org/mailman/listinfo/ompi-packagers
>>
>>
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Re: [OMPI packagers] Possible to have multiple OpenMPIs simultaneously?

2020-11-29 Thread Aisha Tammy via ompi-packagers
On 11/29/20 7:45 PM, Gilles Gouaillardet wrote:
> Aisha,
>
> yes, you can install multiple Open MPI implementations in parallel,
> simply use a different prefix when running configure.
>
> Newer versions of Open MPI support the latest MPI standard 
Makes sense :D
> (there is
> not a direct link between an Open MPI version
> and the MPI standard version though).
Do all OpenMPI major versions support the latest standard?
That would simplify things a lot :D
> That being said, with the exception of a few removed/deprecated
> subroutines, a given version of the MPI standard is a superset of the
> previous versions.
> This is at the source level, and Open MPI does not generally guarantee
> ABI compatibility between two major versions.
Makes sense too. I was not expecting ABI compatibility between major versions.
> Last but not least, keep in mind several packages depend on MPI, for
> example mpi4py (python bindings), parallel FFTW (Fast Fourier
> Transformations), parallel hdf5/netcdf (I/O).
> So since Open MPI has generally no ABI compatibility between major
> versions, you would also need multiple versions of the dependents
> packages (one per Open MPI version).
Yes, I am aware that we would need multiple "slots" for each dependent
packages. We have a half finished project that was started a couple
of years ago which does this slotting of packages and MPI implementations.

Thanks a lot for the answers.

The unfortunate reality is that the default MPI pakages are badly managed in 
almost
all operating systems and any decent cluster has a sysadmin who cooks
up a solution for their use case :(
Even users who want to use OpenMPI, most of the times, install it manually to
tune and get a better control over it.

Making the default packages saner at the operating system level should hopefully
help a lot of people.

Best,
Aisha

> Cheers,
>
> Gilles
>
> On Mon, Nov 30, 2020 at 6:00 AM Aisha Tammy via ompi-packagers
>  wrote:
>>  Hi,
>>   I am a package manager for Gentoo Linux and we are currently trying
>> to get better MPI support for our package tree.
>>
>> A curious question was whether it was possible to have multiple OpenMPI
>> implementations installed in parallel?
>> There seem to be multiple OpenMPI versions being supported and presumably
>> they are supporting different standards of MPI - 2, 3, 3.1 ?
>>
>> Am I correct in making this assumption?
>> If so, it should be possible to allow multiple OpenMPI versions together.
>>
>> Thanks a lot,
>> Aisha
>>
>> ___
>> ompi-packagers mailing list
>> ompi-packagers@lists.open-mpi.org
>> https://rfd.newmexicoconsortium.org/mailman/listinfo/ompi-packagers
> ___
> ompi-packagers mailing list
> ompi-packagers@lists.open-mpi.org
> https://rfd.newmexicoconsortium.org/mailman/listinfo/ompi-packagers

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