Changes between Version 12 and Version 13 of cypress/using


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Timestamp:
Apr 13, 2015 12:39:43 PM (7 years ago)
Author:
cmaggio
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  • cypress/using

    v12 v13  
    3737On your desktop you would open a terminal, compile the code using your favorite c compiler and execute the code. You can do this without worry as you are the only person using your computer and you know what demands are being made on your CPU and memory at the time you run your code. On a cluster, many users must share the available resources equitably and simultaneously. It's the job of the resource manager to choreograph this sharing of resources by accepting a description of your program and the resources it requires, searching the available hardware for resources that meet your requirements, and making sure that no one else is given those resources while you are using them.
    3838
    39 Occasionally the manager will be unable to find the resources you need due to usage by other user. In those instances your job will be "queued", that is the manager will wait until the needed resources become available before running your job. This will also occur of the total resources you request for all your jobs exceed the limits set by the cluster administrator. This ensures that all users have equal access to the cluster.
     39Occasionally the manager will be unable to find the resources you need due to usage by other user. In those instances your job will be "queued", that is the manager will wait until the needed resources become available before running your job. This will also occur if the total resources you request for all your jobs exceed the limits set by the cluster administrator. This ensures that all users have equal access to the cluster.
    4040
    41 The take home point here is this: in a cluster environment a user submits jobs to a resource manager, which, in turn, runs an executable(s) for the user. So how do you submit a job request to the resource manager? Job requests take the form of scripts, called job scripts. These scripts contain script directives, which tell the resource manager what resources the executable requires. The user then submits the job script to the scheduler.
     41The take home point here is this: in a cluster environment a user submits jobs to a resource manager, which in turn runs an executable(s) for the user. So how do you submit a job request to the resource manager? Job requests take the form of scripts, called job scripts. These scripts contain script directives, which tell the resource manager what resources the executable requires. The user then submits the job script to the scheduler.
    4242
    4343The syntax of these script directives is manager specific. For the SLURM resource manager, all script directives begin with "#SBATCH". Let's look at a basic SLURM script requesting one node and one core on which to run our helloworld program.