IBM Power Systems 775, Manual

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IBM Power Systems 775 for AIX and Linux HPC Solution
2.6 Running workloads by using IBM LoadLeveler
LoadLeveler manages both serial and parallel jobs, including OpenMP, MPI, and Hybrid (MPI
+ OpenMP) application on a Power 775 system. The job is submitted to LoadLeveler cluster
through the job command file (JCF), and each job is allocated available resources in the
Power 775 cluster. It is necessary to compose the job command file at the beginning of the
process to run the job in the LoadLeveler cluster.
2.6.1 Submitting jobs
You describe the job you want to submit and run within the job command file. The job
command file includes some of the LoadLeveler keyword statements.
For example, to specify a binary that is executed, you use the executable keyword. To specify
a shell script that is executed, the executable keyword also is used; however, if the keyword is
not used, LoadLeveler assumes that the job command file is the executable.
As shown in Example 2-14, the llclass command is used to ascertain class information
about the current LoadLeveler cluster. Example 2-14 shows that the Y_Class and the
X_Class classes are available in the LoadLeveler cluster. The available class name is used to
compose a LoadLeveler Job Command File (JCF) with the class keyword.
Example 2-14 llclass command
$ llclass
Name MaxJobCPU MaxProcCPU Free Max Description
d+hh:mm:ss d+hh:mm:ss Slots Slots
--------------- -------------- -------------- ----- ----- ---------------------
Y_Class undefined undefined 190 190
X_Class undefined undefined 190 190
Job Command File for a serial job
Figure 2-19 is a sample job command file for a serial job that shows that jcf keyword
#@rset_support=rset_mcm_affinity is used instead of export MEMORY_AFFINITY=MCM.
Figure 2-19 Job Command File for serial job
#!/bin/ksh
# @ job_name = myjob.serial
# @ job_type = serial
# @ class = X_Class
# @ resources = ConsumableCpus(1)
# @ output = $(job_name).out
# @ error = $(job_name).err
# @ queue
export MEMORY_AFFINITY=MCM
./serial.exe