Job Classes and Scheduling
LoadLeveler is configured with the following limits and classes (defining the number of midplanes to be used and ordered by descending priority):
|Class Name||Nodes||Max. Runtime||Default Runtime||Max. Jobs per User||Running on BasePartition|
|m144||65537 - 73728||24:00:00||06:00:00||-||on demand only|
|m128||32769 - 65536||24:00:00||06:00:00||-||on demand only|
|m064||24577 - 32768||24:00:00||06:00:00||-||all|
|m048||16385 - 24576||24:00:00||06:00:00||-||all|
|m032||8193 - 16384||24:00:00||06:00:00||-||all|
|m008||2049 - 4096||24:00:00||06:00:00||-||all|
|m004||1025 - 2048||24:00:00||06:00:00||-||all|
|m002||513 - 1024||24:00:00||06:00:00||-||all|
|m001||257 - 512||24:00:00||06:00:00||-||all|
|small||32 - 256||00:30:00||00:30:00||2||R87-M0, R87-M1|
|nocsmall||32 - 256||00:30:00||00:30:00||1||R87-M0, R87-M1|
The job class is automatically enforced by LoadLeveler depending on the size of a job. The scheduler prioritizes the idle jobs regarding to the class priority, the job submission time, the user's quota, and the number of jobs a user has already running.
The scheduler runs the job with the highest priority if the necessary resources are available. If the requested resources are not yet available the scheduler uses a backfilling strategy to run lower priority jobs with short duration on available resources as long as doing so will not delay the starting of the highest priority job. The chance for a job to get scheduled increases the smaller the wall clock limit is.