[Pw_forum] HELP: How to submit job on multi-node cluster?
pratikdas63 at gmail.com
Wed May 25 12:50:57 CEST 2016
Dear QE users,
I am not a new user of quantum espresso. Previously I worked on a single
machine of 4 core. I simply worked with mpi by 'mpirun -np 4', and the job
was faster than a serial run.
Now I have a 2 node cluster. Each node consists of 2 processors of 12 core
each. Hence I made a hostfile(for a single node) by specifying
Now my command is
"mpirun --hostfile my_hostfile -np 24 ph.x <input.in> output.out". This run
takes 9hours and 39 minutes.
But when I want to use both nodes by
"mpirun --hostfile my_hostfile -np 48 ph.x <input.in> output.out -ni 6 -nk
It is taking too much time to complete the job. Even it is now almost 26
hours over. 2nd q point calculation is going on.
NB: The job has only 4 q points.
I have also seen this in pw.x run. In a single node, it is taking only
Command: mpirun --hostfile my_hostfile -np 24 pw.x <input.in> output.out.
But in case of both nodes, it is taking almost half an hour.
Command: mpirun --hostfile my_hostfile -np 48 pw.x <input.in> output.out
Can anyone suggest me that why the jobs running on 2 nodes are slower than
the jobs in single node?
Thanks in advance.
Pratik Kumar Das
*Pratik Kr. Das*
High Pressure and Temperature Lab
Faculty of Science
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