Job tracking

This section helps you to understand the factors that affect the performance of the event manager and identifies actions to address those factors. The event manager subtask is most often a victim of poor performance by other users of the current plan lock, it is rarely the cause.

Recognizing the indicators

These indicators can highlight performance problems in the event manager subtask:

• STATMSG(CPLOCK) identifies a long HOLD time for the EMGR.
• STATMSG(CPLOCK) identifies a long WAIT time for the WSA, NMM, or GS when compared to EMGR.
• Long delay from event creation to event processed. Compare the creation time in the event record with the job tracking log record time. Performance Reporter for MVS™, Tivoli® Decision Support for OS/390® and EPDM provide tables to report event delay; the IBM Tivoli Workload Scheduler for z/OS audit program lists creation time and controller processing time for events.
• The total events received by the event manager compared to those that are actually of interest to IBM Tivoli Workload Scheduler for z/OS.
• Unusually high number of suspended events, identified by 2 in column 53 of the job tracking record. You can also identify suspended events by locating SUSPENDED in the report produced by the IBM Tivoli Workload Scheduler for z/OS audit package.
• User exits involved in tracking, EQQUX007 and in the tracker EQQUX004, EQQUX005, and EQQUX006.

The connection method and the tracker’s performance are also indicators.

Recommendations

Consider these recommendations:

• Reduce the number of suspended events by lowering ERWAIT time.
• Tune the trackers.
• Eliminate as many trivial events as possible:
  • Use STEPEVENTS(ABEND) or STEPEVENTS(NZERO) rather than STEPEVENTS(ALL).
  • Specify PRINTEVENTS(NO) if you do not track print operations.
  • Filter the test workload using EQQUX004.
  • Filter type 5 events, except those with EXROPCAN, if printing is not of interest.
• Use NCF or XCF connections rather than starting event readers. When you use NCF or XCF for communications, be sure to use the EWSEQNO option in the EWTROPTS initialization statement. Starting a specific event reader task in the tracker is not required and dramatically increases I/O to the event data set and more importantly the path length for an event to reach the controller.
• Ensure EQQUX007 is performing well, if used. The current plan lock is held when the exit is taken.