[slurm-users] Dependencies with singleton and after

Michael Di Domenico mdidomenico4 at gmail.com
Wed Aug 28 14:26:00 UTC 2019

just curious.  if you leave out the singleton, do you get the behavior
as expected?

On Tue, Aug 27, 2019 at 9:42 AM Jarno van der Kolk <jvanderk at uottawa.ca> wrote:
> Hi all,
> I'm still puzzled by the expected behaviour of the following:
> $ sbatch --hold fakejob.sh
> Submitted batch job 25909273
> $ sbatch --hold fakejob.sh
> Submitted batch job 25909274
> $ sbatch --hold fakejob.sh
> Submitted batch job 25909275
> $ scontrol update jobid=25909273 Dependency=singleton
> $ scontrol update jobid=25909274 Dependency=singleton,after:25909275
> $ scontrol update jobid=25909275 Dependency=singleton,after:25909273
> $ scontrol release 25909273 25909274 25909275
> I expected these to be executed as 25909273, 25909275, 25909274. However, it seems that singletons are executed in order of submission so that this leads to a circular dependency. That is, 25909274 depends on 25909275 due to "after", and 25909275 depends on 25909274 due to "singleton" plus order of submission.
> From the man page for sbatch, that wasn't really clear to me:
>              singleton
>                      This  job  can begin execution after any previously launched jobs sharing the same
>                      job name and user have terminated.
> I'm somewhat interested in creating a patch for this, but before I can look into this, I'll need to know what the expected behaviour is.
> If "launched" means submitted to the queue and preserving order, then I should focus on the circular dependency detection.
> If "launched" means entered the running state without preserving order, then I should focus on the dependency resolving.
> Any thoughts on this?
> Thanks,
> Jarno
> Jarno van der Kolk, PhD Phys.
> Analyste principal en informatique scientifique | Senior Scientific Computing Specialist
> Solutions TI | IT Solutions
> Université d’Ottawa | University of Ottawa

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