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Equivalence classes are a way to group similar jobs together. Once one job in a class can not run, the scheduler knows the rest of the jobs in that class can not run. This allows the scheduler to be more efficient by not having to consider all the jobs in the system.
Similar Similarity is defined by the values of the following attributes and resources. If two jobs have equal values of all the attributes and resources in use, then they are in the same equivalence class. An attribute or resource is used based on the situation described.
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All resources in the sched_config resources line in the select statement
- Jobs in the suspended state use a special scheduler-generated select statement. This specially generated select statement is based on the existing select statement and the vnodes the job is running on. This will likely result in a suspended job running in its own equivalence class.
All resources in the sched_config resources line from Resource_List (qsub -l)
Time based resources such as : walltime, cput, max_walltime, and min_walltime from Resource_List
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Visibility: Scheduler log message at DEBUG3
Description: "Number of job equivalence classes: N" where N is the number of job equivalence classes