Tuning Performance › Performance Considerations When Writing NCL

Performance Considerations When Writing NCL

When writing NCL, the following points should be considered to ensure that your system performance does not suffer:

• Ensure that the &CONTROL RESCAN option is only used around statements to which it applies. Rescanning every NCL statement slows the system down.
• Use suppressed comments because they occupy no storage. They add an insignificant overhead to the procedure load process only.
• Use modular programming.
• Use the NCLTEST command when testing NCL to circumvent the retain and autoshare facility.
• Do not use static and dynamic PREPARSE facilities for panels unless they are essential to a specific panel display.
• In any NCL procedures that display panels, think about the number of variables that are active across any panel displays. The large number of concurrent processes executing can result in excessive virtual storage usage. Comment out any unneeded variables before any of these displays.
• Reduce the overheads of using &CALL repeatedly to call a module by using one of the following methods:
  • Use the LOAD MOD=module_name command, if the module is reentrant, to load it once into storage.
  • Use the SUBSYS facility to attach the program once.