Thanks for the info Jeff! All of my "test" nodes are temporarily busy,
but I should be able to play with this some more tomorrow.
I'll update the post if I have more questions or find any additional
tips ;-)
Jeff F. Pummill
Senior Linux Cluster Administrator
University of Arkansas
Fayetteville, Arkansas 72701
(479) 575 - 4590
http://hpc.uark.edu
"A supercomputer is a device for turning compute-bound
problems into I/O-bound problems." -Seymour Cray
Jeff Squyres wrote:
Ick; I'm surprised that we don't have this info on the FAQ. I'll try
to rectify that shortly.
How are you launching your jobs through SLURM? OMPI currently does
not support the "srun -n X my_mpi_application" model for launching
MPI jobs. You must either use the -A option to srun (i.e., get an
interactive SLURM allocation) or use the -b option (submit a script
that runs on the first node in the allocation). Your script can be
quite short:
#!/bin/sh
mpirun my_mpi_application
Note that OMPI will automatically figure out how many cpu's are in
your SLURM allocation, so you don't need to specify "-np X". Hence,
you can run the same script without modification no matter how many
cpus/nodes you get from SLURM.
It's on the long-term plan to get "srun -n X my_mpi_application"
model to work; it just hasn't bubbled up high enough in the priority
stack yet... :-\
On Jun 20, 2007, at 1:59 PM, Jeff Pummill wrote:
Just started working with OpenMPI / SLURM combo this morning. I can
successfully launch this job from the command line and it runs to
completion, but when launching from SLURM they hang.
They appear to just sit with no load apparent on the compute nodes
even though SLURM indicates they are running...
[jpummil@trillion ~]$ sinfo -l
Wed Jun 20 12:32:29 2007
PARTITION AVAIL TIMELIMIT JOB_SIZE ROOT SHARE GROUPS
NODES STATE NODELIST
debug* up infinite 1-infinite no no all
8 allocated compute-1-[1-8]
debug* up infinite 1-infinite no no all
1 idle compute-1-0
[jpummil@trillion ~]$ squeue -l
Wed Jun 20 12:32:20 2007
JOBID PARTITION NAME USER STATE TIME TIMELIMIT
NODES NODELIST(REASON)
79 debug mpirun jpummil RUNNING 5:27
UNLIMITED 2 compute-1-[1-2]
78 debug mpirun jpummil RUNNING 5:58
UNLIMITED 2 compute-1-[3-4]
77 debug mpirun jpummil RUNNING 7:00
UNLIMITED 2 compute-1-[5-6]
74 debug mpirun jpummil RUNNING 11:39
UNLIMITED 2 compute-1-[7-8]
Are there any known issues of this nature involving OpenMPI and SLURM?
Thanks!
Jeff F. Pummill
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