How to optimize your programs with IPA

To use IPA to optimize your program or service program objects, perform the following steps:
  1. Make sure that you compile all of the modules necessary for the program or service program with MODCRTOPT(*KEEPILDTA) and with an optimization level of 20 or greater (preferably 40). You can use the DSPMOD command with the DETAIL(*BASIC) parameter to verify that a single module is compiled with the correct options. The Intermediate language data field will have a value of *YES if IL data is present. The Optimization level field indicates the optimization level of the module.
  2. Specify IPA(*YES) on the CRTPGM or CRTSRVPGM command. When the IPA portion of the bind runs, the system displays status messages to indicate IPA progress.
You can further define how IPA optimizes your program by using the following parameter:
  • Specify IPACTLFILE(IPA-control-file) to provide additional IPA suboption information. See IPA control file syntax for a listing of the options you can specify in the control file.

When you specify IPA(*YES) on the CRTPGM command, you cannot also allow updates to the program (that is, you cannot specify ALWUPD(*YES)). This is also true for the ALWLIBUPD parameter on the CRTSRVPGM command. If specified along with IPA(*YES), the parameter must be ALWLIBUPD(*NO).