Excluding specific load modules and compile units

In some cases, you might know that there are certain load modules or compile units that you do not want to debug. In this case, you can improve performance by informing z/OS® Debugger to not load debug data for these load modules or compile units.

You can use the NAMES EXCLUDE command to indicate to z/OS Debugger that it does not need to maintain debug data for these modules. When you use the NAMES EXCLUDE command to exclude executable modules, there are situations where z/OS Debugger requires debug data for the excluded modules. The following list, while not comprehensive, describes some of the possible situations:

• The entry point of an enclave.
• The next higher-level compile unit when a STEP RETURN command is executing.
• Compile units that appear in the call chain of a compile unit where z/OS Debugger has suspended execution.
• The next higher-level compile unit when the user-program has been suspended at an AT EXIT breakpoint.

Also, when you enter a deferred AT ENTRY command, z/OS Debugger generates an implicit NAMES INCLUDE command for the load module and compile unit that is the target of the deferred AT ENTRY. If these names appear later in the program, z/OS Debugger will not exclude them even if you specified them in a previous NAMES EXCLUDE command.

In all of the above situations, z/OS Debugger loads debug data as required and these modules might become known to z/OS Debugger.

Refer to the following topics for more information related to the material discussed in this topic.

• Related references
• "NAMES command" in IBM® z/OS Debugger Reference and Messages