z/OS workload management and service policies

If users who work in a multi-user address space are assigned to the same service policy, normal WLM behavior is assured. All user work in such an address space receives equal treatment. In an operating system dispatcher queue priority, the z/OS workload management (WLM) manages running work at the address space level.

Since traditional z/OS workloads were either one job or one online user at a time per address space, the service policy of the address space is considered when determining dispatcher priority. When multi-user address spaces, such as CICS or WebSphere Application Server were introduced, the fundamental WLM/dispatcher model was not changed, but rather accommodated.

However, in a multi-user address space where the user work is assigned to mixed service policies, only the most aggressive service policy is considered for purposes of managing dispatcher priority. The service policy with the most stringent performance goal and highest importance governs the dispatch priority of such an address space.

Running mixed service policy in a single address space has a negative consequence. The work of lesser importance in such an address space receives the same dispatcher prioritization as the most important work in the address. This situation occurs because the most aggressive service policy governs that prioritization. An attempt by the user to achieve service policy differentiated resource management is undermined.