The DB2® workload management dispatcher is a built-in DB2 technology by which you can specifically allocate CPU resources to work that is being executed on a database server. CPU resource entitlements can be controlled by using CPU shares and CPU limit attributes on DB2 service classes.
Particularly useful under workload conditions that strain the system CPU resources, the dispatcher can effectively manage service class CPU resource entitlements with attributes such as the uncapped (almost unrestricted) soft CPU shares, and the two capped (limited) attributes: hard CPU shares and CPU limits. You can use the uncapped soft CPU shares to give high-priority-work service classes any unused CPU resources. In addition, you can enforce controls on the CPU resource entitlements by using capped hard CPU shares or CPU limits assigned to low-priority-work service classes, thereby limiting their impact on high-priority work. Under conditions where the system CPU resources are less strained, you can use one or both of the capped attributes, without the need to assign uncapped attributes, to effectively control the CPU resource entitlements between service classes running in a typical, underrun-CPU environment.
The workload management dispatcher infrastructure operates at the instance level in the DB2 database manager. The dispatcher operates by limiting the number of executing agents to be dispatched to the operating system (OS) and how long each agent is allowed to execute, at any given time. The number of executing agents that can be dispatched at the same time is referred to as the dispatch concurrency level.