[slurm-users] MPI jobs via mirun vs. srun through PMIx.

[Juergen Salk]

* Loris Bennett <loris.bennett at fu-berlin.de> [190917 07:46]:
> >
> >>But I still don't get the point. Why should I favour `srun ./my_mpi_program´ 
> >>over `mpirun ./my_mpi_program´? For me, both seem to do exactly the same 
> >>thing. No? Did I miss something?
> >
> >>Best regards
> >>Jürgen
> >
> > Running a single job in isolation doesn't properly illustrate what slurm does in the larger sense.
> > 
> > [...]
> > 
> 
> I think Jürgen may well be aware of what Slurm does in the larger sense.

Dear Loris,

thank you for your clarification. You are right. It seems that I have
phrased my question somewhat misleadingly.

For our next cluster we will switch from Moab/Torque to Slurm and have
to adapt the documentation and example batch scripts for the users.
Therefore, I wonder if and why we should recommend (or maybe even urge) 
our users to use srun instead of mpirun/mpiexec in their batch scripts 
for MPI jobs. 

> I suspect the question, which I also have, is more like:
> 
>   "What difference does it make whether I use 'srun' or 'mpirun' within
>    a batch file started with 'sbatch'."

That's exactly the question I wanted to ask.

Thanks again.

Best regards
Jürgen

-- 
Jürgen Salk
Scientific Software & Compute Services (SSCS)
Kommunikations- und Informationszentrum (kiz)
Universität Ulm
Telefon: +49 (0)731 50-22478
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