General Information

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User Guide for NY Blue/P


Overview

This user guide documents topics of interest to the end users of NY Blue/P such as using the compilers and batch job submission.

Local and some offsite documentation can be found in the sidebar at the left.

The hostname for the front end node of NY Blue is fenp.bluegene.bnl.gov

Blue Gene is not a typical parallel computer. It is meant for codes that scale well into hundreds or even thousands of processors. The processors in Blue Gene are slower than those on the BNL Linux clusters. So, unless your code scales well and so can benefit from using a lot of processors, you may be better off running it with fewer processors on e.g. a standard Linux cluster.

The compute nodes on which your job runs are rebooted prior to running your job on them, ensuring that there is no "junk" remaining from whatever jobs ran on those nodes previously. The nodes are also exclusively allocated to your job.

To run on NY Blue, you must submit your job to the LoadLeveler batch system.

If you find any errors on these pages please notify NY Blue Web Administrator

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Simple Example: Compile, Link, Run

  1. Copy the source code for a C language "Hello World" MPI program to any test subdirectory of your home directory:
     
    cp /bgsys/local/samplecodes/c/hello.c /home/johndoe/tests/c/
     
  2. cd /home/johndoe/tests/c
     
  3. Compile and Link:
    mpixlc -o helloc.exe hello.c
     
  4. Create a LoadLeveler batch file myjob.ll, specifying in it the size of the dynamic partition that LoadLeveler should allocate for your batch job. Specify between 64 and 2048 nodes. You can use example.ll as a template in creating myjob.ll
     
  5. Then submit the job:
    llsubmit myjob.ll
     
  6. The output and (if any) error files 3236.out and 3236.err respectively appear in /home/johndoe/tests/c when the job has completed.
     
  7. This is only a quick example, see the instructions for running LoadLeveler batch jobs.  

Example Description: The batch job submission example above uses the mpich wrapper mpixlc for the IBM C cross compiler to create an executable for the compute nodes, then submits a LoadLevler batch job to run that executable on the NY Blue compute nodes.

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