Exclusive sessions


Use sparingly - it denies resources to other users.

We ask that you don't run anymore than 5 exclusive jobs.

During normal usage when you start a session on a node, your job will execute on a single core/slot.

Certain applications are multi-threaded in their nature, which means that they will use more than one core/slot to gain performance.  It is possible that a multi-threaded application will use all of the possible resources on a node. This will obviously have an impact on other users of the node, who may already be running jobs on the same node. 

Therefore if you are running multi-threaded code you need to ask for exclusive use of a node.  You should bear in mind when using this particular directive (--exclusive), you reserve all of the cores/slots on the node (depending on the node this may be up to 28 slots/cores).  This will mean your jobs are likely to take longer to be allocated to a node, because a node with no other jobs running has to be available.

All of the following applications should be run with the (--exclusive) directive:

  • Stata15/16 MP16
  • Gaussian
  • Gaussview
  • Matlab (Parallel Computing Toolbox)

If you have a need for more resource or wish to discuss this further please email hpc.admin@uea.ac.uk

Using exclusive sessions

  • Starting an exclusive access interactive session

interactive-x

interactive-gpu-x

We have not implemented an exclusive hmem option because it is too expensive in resources, and would have too big an impact on other users.

  • To request an exclusive batch job

    note you need to adjust the ntasks to the number of slots on the node.  See queues

for example
#SBATCH -p compute-16-64
#SBATCH --ntasks=16

or

#SBATCH -p compute-24-96
#SBATCH --ntasks=24

Using the (--exclusive) directive in a jobscript (Gaussian) 

#!/bin/bash
#SBATCH --mail-type=ALL           #Mail events (NONE, BEGIN, END, FAIL, ALL)
#SBATCH --mail-user=<username>@uea.ac.uk    # Where to send mail
#SBATCH -p compute-16-64                 #Which queue to use
#SBATCH --exclusive                      # set exclusive use of node
#SBATCH --ntasks=16                          # all slots on the node
#SBATCH --job-name=gaussian-test_job #Job name
#SBATCH -o gaussian-test-%j.out       #Standard output log
#SBATCH -e gaussian-test-%j.err       #Standard error log
#set up environment
module add gaussian/16B01
 #run the application
g09 gauss_opt.inp

Using the (--exclusive) directive in a jobscript (Stata 15 MP16)

 #run the application#set up environment#!/bin/bash
#SBATCH --mail-type=ALL           #Mail events (NONE, BEGIN, END, FAIL, ALL)
#SBATCH --mail-user=<username>@uea.ac.uk    # Where to send mail
#SBATCH -p compute-16-64                  #Which queue to use
#SBATCH --exclusive                      # set exclusive use of node
#SBATCH --ntasks=16                         # all slots on the node
#SBATCH --job-name=stata-test_job #Job name
#SBATCH -o stata-test-%j.out       #Standard output log
#SBATCH -e stata-test-%j.err       #Standard error log
#set up environment
module add stata/15
 #run the application
stata-mp -b do stata15_example.dostata

Jobs which need a graphical user interface

eg Matlab, Stata - You need to have x forwarding configured for this to work.