Subsystem-specific performance hints

For CICS 4.1 and higher releases, WLM collects delay samples for each performance block. Because the number of performance blocks created is based on the MAXTASK value (a value of 100 means 100 performance blocks created per region), a MAXTASK value that is too high can cause a large sampling overhead when a CICS workload is switched to goal mode. If MAXTASK has been set to an arbitrarily high value, it should be reduced to a true “high water mark” value.

Work in subsystems that use enclaves (see Subsystem support for goal types and multiple periods for a list of these subsystems) can suffer performance degradation if left unclassified in the service definition. If you do not add classification rules for this work in your service definition, it will be assigned to the SYSOTHER service class, which has a discretionary goal. Using the WLM application, you need to add classification rules to assign the work to service classes with appropriate response time or velocity goals.

As a general rule, it's a good idea to keep an eye on the SYSOTHER service class through RMF™ or another monitor. Any service accumulating in the SYSOTHER service class is a signal that you have unclassified work in your system.