IBM LoadLeveler for AIX 5L: Using and Administering

Considerations for integrating LoadLeveler with AIX Workload Manager

Another administrative setup task you must consider is whether you want to enforce resource usage of ConsumableCPUs and ConsumableMemory. If you want to control these resources, AIX Workload Manager (WLM) can be integrated with LoadLeveler to balance workloads at the machine level. Workload balancing is done by assigning relative priorities to job processes. These job priorities prevent one job from monopolizing system resources when that resource is under contention. To integrate LoadLeveler and WLM you must:

1. Define ConsumableCpus, ConsumableMemory, or both as consumable resources in the SCHEDULE_BY_RESOURCES global configuration keyword. This enables the LoadLeveler scheduler to consider these consumable resources.
2. Define ConsumableCpus, ConsumableMemory, or both in the ENFORCE_RESOURCE_USAGE global configuration keyword. This enables enforcement of these consumable resources by AIX WLM.
3. Using the resources keyword of the machine stanza, define the CPU and real memory machine resources available for user jobs.
   • The ConsumableCpus reserved word accepts a count value of "all." This indicates that the initial resource count will be obtained from the Startd machine update value for CPUS.
   • If no resources are defined for a machine, then no enforcement will be done on that machine.
   • If the count specified by the administrator is greater than what the Startd update indicates, the initial count value will be reduced to match what the Startd reports.
   • If the count specified by the administrator is less than what the Startd update indicates, the WLM resource shares assigned to a job will be adjusted to represent that difference and a WLM softlimit will be defined for each WLM class. For example, if the administrator defines 8 CPUs on a 16 CPU machine, then a job requesting 4 CPUs will get a share of 4 and a softlimit of 50%.
   • Use caution when determining the amount of real memory available for user jobs. A certain percentage of a machine's real memory will be dedicated to the Default and System WLM classes and will not be included in the calculation of real memory available for users jobs. Start LoadLeveler with the ENFORCE_RESOURCE_USAGE keyword enabled and issue wlmstat -v -m. Look at the npg column to determine how much memory is being used by these classes.
4. Decide if all jobs should have their CPU or real memory resources enforced and then define the ENFORCE_RESOURCE_SUBMISSION global configuration keyword.
   • If the value specified is true, LoadLeveler will check all jobs at submission time for the resources keyword. The job's resources keyword needs to have the same resources specified as the ENFORCE_RESOURCE_USAGE keyword in order to be submitted.
   • If the value specified is false, no checking will be done and jobs submitted without the resources keyword will not have resources enforced and may interfere with other jobs whose resources are enforced.
   • To support existing job command files without the resources keyword, the default_resources keyword in the class stanza can be defined. The default_resources keyword needs to be defined in the default interactive class to support interactive jobs.

For more information on the ENFORCE_RESOURCE_USAGE and the ENFORCE_RESOURCE_SUBMISSION keywords, see Step 4: Define consumable resources.