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Getting started

CSC uses a batch job system to execute computing tasks on our supercomputers.

Typically, a batch job first loads a software environment using the module system and then executes a program to do some computing. A batch job is also required to specify the resources needed for the execution of the job.

This chapter introduces the basics of creating and submitting batch jobs using the SLURM (Simple Linux Utility for Resource Management) batch job system.

Note that also interactive tasks (other than compiling, moving data and light pre- and postprocessing) are to be done via batch job system.

Key concepts of the CSC batch job system

  • Jobs do not run instantly but are put in a queue
    • The jobs are executed when there are resources available. The timing also depends on the priority score.
    • The priority score for a job exists to ensure fair sharing of computational resources between all the users of the cluster.
  • The starting time for a job cannot be predicted
    • It depends heavily on the actual runtimes for all user jobs and whether new jobs are submitted, see FAQ.
  • Computational resources (runtime, memory, number of cores) are requested explicitly
    • If the time or memory limits are exceeded, the job will be terminated.

To get started with running your application on Puhti:

  1. Create a batch job script for Puhti
  2. Submit a batch job

If you are already familiar with SLURM, check out our example batch job scripts for Puhti or example batch job scripts for Mahti.

Note

Please see the LUMI documentation for how to get started with running jobs on the LUMI supercomputer. LUMI uses also the SLURM batch queue system, so the differences between running on CSC supercomputers and LUMI are minor.