[slurm-users] Question about sbatch options: -n, and --cpus-per-task

[David Henkemeyer]

“ Will launch 64 instances of your application, each bound to a single cpu”

This is true for srun, but not for sbatch.

A while back, we did an experiment using “hostname” to verify.

On Thu, Mar 24, 2022 at 12:47 PM Ralph Castain <rhc at pmix.org> wrote:

> Well, there is indeed a difference - and it is significant.
>
> > On Mar 24, 2022, at 12:32 PM, David Henkemeyer <
> david.henkemeyer at gmail.com> wrote:
> >
> > Assuming -N is 1 (meaning, this job needs only one node), then is there
> a difference between any of these 3 flag combinations:
> >
> > -n 64 (leaving cpus-per-task to be the default of 1)
>
> Will launch 64 instances of your application, each bound to a single cpu
>
> > --cpus-per-task  64 (leaving -n to be the default of 1)
>
> Will run ONE instance of your application (no binding if the node has 64
> cpus - otherwise, the proc will be bound to 64 cpu's)
>
> > --cpus-per-task 32 -n 2
>
> Will run TWO instances of your application, each bound to 32 cpu's
>
> >
> > As far as I can tell, there is no functional difference. But if there is
> even a subtle difference, I would love to know what it is!
> >
> > Thanks
> > David
> > --
> > Sent from Gmail Mobile
>
>
> --
Sent from Gmail Mobile
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