z/OS Generalized Trace Facility (GTF)

Use the z/OS® generalized trace facility (GTF) to record a wide range of system-level events. The trace activity is controlled from the z/OS system console using the MODIFY command.

Output is spooled to a sequential data set that is used by a generalized formatting utility. You can write exit routines that are called by the formatting utility to edit the trace records and present the data as desired.

The following GTFPARS reports are of special interest for IMS:

• Job Summary report: This report lists the following for each of the IMS message regions and for the control region: SVC counts, loading of modules, and EXCP, SIO, and IO timings.
• Detail Trace report lists the following information:
  • For IMS message regions: Detailed analysis of program management activity. This analysis gives you the ability to investigate event sequences in detail.
  • For the IMS control region: Database I/O that is handled in the control region, and network-related activity.
  • For all IMS regions running in parallel: Contention between regions (for example, contention for access to a program library), and the flow of control from the control region to the MPPs.
• Job Summary report of Master Address Space in z/OS: This report shows system paging activity.
• Detail Trace report of Master Address Space in z/OS: You can use this report for a detailed investigation of delays caused by paging.
• System Summary report: You can use this report for I/O subsystem analysis for all IMS data sets.