System-level Tuning

The first area to consider when tuning your region is at the system level. The following points outline system level performance considerations:

For z/OS systems, the performance group and dispatching priority can affect the performance of your region. High-priority systems should be in the same domain as VTAM and just below it in dispatching priority.
In terms of tuning, your product can be regarded as equivalent to CICS or IMS. All system tuning rules that apply to other online systems should be used with these systems to ensure that your product region is not starved for real storage.
Data set placement is important to consider when increasing the performance of your system. The PANELS, MODS, and NCL COMMANDS data sets can have a large amount of I/O activity on them. For this reason, consider placing these data sets on volumes and paths that are not otherwise busy.
Running your product region as non-swappable can help to increase response time, which is important when the overall activity rate is low but quick response is important. The NONSWAP parameter group is used to specify whether your product region is non-swappable (the default).

Note: Some products must run non-swappable.