Re: [OMPI users] Regarding process binding on OS X with oversubscription

[Sajid Ali via users]

Hi George,

That clarifies all my questions. Thanks for taking the time to answer them!

Re: [OMPI users] Regarding process binding on OS X with oversubscription

[George Bosilca via users]

Sajid,

`--bind-to-core` should have generated the same warning on OSX. Not sure
why this is happening, but I think the real bug here is the lack of warning
when using the deprecated argument.

Btw, the current master does not even accept 'bind-to-core', instead it
complains about 'unrecognized option'.

  George.


On Thu, Mar 17, 2022 at 4:04 PM Sajid Ali 
wrote:

> Hi George,
>
> Thanks a lot for the confirmation!
>
> When one uses the deprecated `--bind-to-core` option, is OpenMPI silently
> ignoring this on OS X? Would this be indicated with increased verbosity
> when using mpiexec?
>
> Thank You,
> Sajid Ali (he/him) | PhD Candidate
> Applied Physics
> Northwestern University
> s-sajid-ali.github.io
>

Re: [OMPI users] Regarding process binding on OS X with oversubscription

[Sajid Ali via users]

Hi George,

Thanks a lot for the confirmation!

When one uses the deprecated `--bind-to-core` option, is OpenMPI silently
ignoring this on OS X? Would this be indicated with increased verbosity
when using mpiexec?

Thank You,
Sajid Ali (he/him) | PhD Candidate
Applied Physics
Northwestern University
s-sajid-ali.github.io

Re: [OMPI users] Regarding process binding on OS X with oversubscription

[Brice Goglin via users]

Hello

OS X doesn't support binding at all, that's why hwloc and OpenMPI don't 
support it either.


Brice


Le 17/03/2022 à 20:23, Sajid Ali via users a écrit :


Hi OpenMPI-developers,

When trying to run a program with process binding and oversubscription 
(on a github actions CI instance) with |--bind-to-core|, OpenMPI’s 
mpiexec executes the programs with no issues.


Noting that |--bind-to core| is more portable (MPICH’s mpiexec also 
accepts it) and that |--bind-to-core| is deprecated, I tried switching 
to it. However, OpenMPI now complains that it cannot perform process 
binding on OS X with the following message:


|On OS X, processor and memory binding is not available at all (i.e., 
the OS does not expose this functionality). |


Could someone confirm whether OpenMPI supports process binding on OS X 
and also comment on why |--bind-to-core| works but |--bind-to core| 
doesn’t? Thanks in advance!


Thank You,
Sajid Ali (he/him) | PhD Candidate
Applied Physics
Northwestern University
s-sajid-ali.github.io 



OpenPGP_signature
Description: OpenPGP digital signature

Re: [OMPI users] Regarding process binding on OS X with oversubscription

[George Bosilca via users]

OMPI cannot support process binding on OSX because, as the message
indicates, there is no OS API for process binding (at least not exposed to
the user-land applications).

  George.


On Thu, Mar 17, 2022 at 3:25 PM Sajid Ali via users <
users@lists.open-mpi.org> wrote:

> Hi OpenMPI-developers,
>
> When trying to run a program with process binding and oversubscription (on
> a github actions CI instance) with --bind-to-core, OpenMPI’s mpiexec
> executes the programs with no issues.
>
> Noting that --bind-to core is more portable (MPICH’s mpiexec also accepts
> it) and that --bind-to-core is deprecated, I tried switching to it.
> However, OpenMPI now complains that it cannot perform process binding on OS
> X with the following message:
>
> On OS X, processor and memory binding is not available at all (i.e.,
> the OS does not expose this functionality).
>
> Could someone confirm whether OpenMPI supports process binding on OS X and
> also comment on why --bind-to-core works but --bind-to core doesn’t?
> Thanks in advance!
>
> Thank You,
> Sajid Ali (he/him) | PhD Candidate
> Applied Physics
> Northwestern University
> s-sajid-ali.github.io
>

[OMPI users] Regarding process binding on OS X with oversubscription

[Sajid Ali via users]

Hi OpenMPI-developers,

When trying to run a program with process binding and oversubscription (on
a github actions CI instance) with --bind-to-core, OpenMPI’s mpiexec
executes the programs with no issues.

Noting that --bind-to core is more portable (MPICH’s mpiexec also accepts
it) and that --bind-to-core is deprecated, I tried switching to it.
However, OpenMPI now complains that it cannot perform process binding on OS
X with the following message:

On OS X, processor and memory binding is not available at all (i.e.,
the OS does not expose this functionality).

Could someone confirm whether OpenMPI supports process binding on OS X and
also comment on why --bind-to-core works but --bind-to core doesn’t? Thanks
in advance!

Thank You,
Sajid Ali (he/him) | PhD Candidate
Applied Physics
Northwestern University
s-sajid-ali.github.io