"Ohlerich, Martin" <martin.ohler...@lrz.de> writes: > Dear Colleagues, > > > already for quite some years now are we again and again facing issues on our > clusters with so-called job-farming (or task-farming) concepts in Slurm jobs > using srun. And it bothers me that we can hardly help users with requests in > this regard. > > > From the documentation > (https://slurm.schedmd.com/srun.html#SECTION_EXAMPLES), it reads like this. > > -------------------------------------------> > > ... > > #SBATCH --nodes=?? > > ... > > srun -N 1 -n 2 ... prog1 &> log.1 & > > srun -N 1 -n 1 ... prog2 &> log.2 &
Unfortunately, that part of the documentation is not quite up-to-date.
The semantics of srun has changed a little the last couple of
years/Slurm versions, so today, you have to use "srun --exact ...". From
"man srun" (version 21.08):
--exact
Allow a step access to only the resources requested for the
step. By default, all non-GRES resources on each node in
the step allocation will be used. This option only applies
to step allocations.
NOTE: Parallel steps will either be blocked or rejected
until requested step resources are available unless --over‐
lap is specified. Job resources can be held after the com‐
pletion of an srun command while Slurm does job cleanup.
Step epilogs and/or SPANK plugins can further delay the
release of step resources.
--
Regards,
Bjørn-Helge Mevik, dr. scient,
Department for Research Computing, University of Oslo
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