On Sat, Nov 14, 2020 at 08:07:47PM +0000, Ralph Castain via users wrote:
> IIRC, the correct syntax is:
>
> prun -host +e ...
>
> This tells PRRTE that you want empty nodes for this application. You can even
> specify how many empty nodes you want:
>
> prun -host +e:2 ...
>
> I haven't tested that in a bit, so please let us know if it works or not so
> we can fix it if necessary.
Works! Thank you.
$ prun --map-by ppr:64:node --host +e -n 1 ./mpitest &
$ prun --map-by ppr:64:node --host +e -n 1 ./mpitest &
MPI World size = 1 processes
Hello World from rank 0 running on nid03835 (hostname nid03835)!
MPI World size = 1 processes
Hello World from rank 0 running on nid03834 (hostname nid03834)!
Should I PR a patch to prun manpage to change this:
-H, -host, --host <host1,host2,...,hostN>
List of hosts on which to invoke processes.
to something like this?:
-H, -host, --host <host1,host2,...,hostN>
List of hosts on which to invoke processes. Pass
+e to allocate only onto empty nodes (i.e. none of
whose cores have been allocated to other prun jobs) or
+e:N to allocate to nodes at least N of which are empty.
