JES2PARM Tuning Considerations

• In the CPU on which the Control‑M monitor runs, increase the IBM‑supplied default (or current) value of PSONUM (number of Process SYSOUT processors) by two or three.
• To avoid performance degradation of Control‑M in a Multi‑Access Spool (MAS) environment, adjust and tune the following MAS Definition (MASDEF) parameters:

  — In the CPU on which the Control‑M monitor runs, increase HOLD and decrease DORMANCY. In all other CPUs, decrease HOLD and increase DORMANCY.

  — The following recommended values are approximations that do not take into account other products that may be sensitive to JES2 utilization rates resulting from changing the current values. The Systems Programmer may want to do further tuning.

  • On the CPU on which Control‑M runs, set the following values:

    PSONUM=5
    MASDEF HOLD=45,DORMANCY=(30,150)

  • On the other CPUs, set the following values:

    MASDEF HOLD=15,DORMANCY=(150,500)

  Note: The HOLD and DORMANCY parameters can by dynamically changed using the following JES2 command: $T MASDEF,HOLD=nnnnnnnn,DORMANCY=(mmmm,nnnn)

• For information on avoiding performance degradation of Control‑M in a non-MAS environment, see "Member-specific Parameter Recommendations" (for hold and dormancy in the MASDEF statement) in the Accessing the Checkpoint Dataset topic of the IBM manual JES2 Initialization and Tuning Reference.

  In particular, note the following recommendation made by IBM:

  "If running a single-processor, the following parameter specifications might be good initial values because there are no other processors waiting to gain access to the queues:"

  +------------------------------------------------------------------------+

  ¦ MASDEF HOLD=99999999,DORMANCY=(10,500)

  +------------------------------------------------------------------------+:

This change enables the JES on the CPU on which Control‑M runs to handle Control‑M requests more efficiently and thereby avoid delays in Control‑M’s analyzing a job’s ending status.

From the Control-M point of view, there are two JES dependent time intervals:

1. the time interval when the JES checkpoint is available (JES window),
2. the time interval between the JES windows.

The optimal value of the MULTISUB parameter is the smaller of the following two numbers:

• the max number of prepared jobs that Control-M can write into the JES internal reader during an interval (1).
• the max number of jobs that Control-M can prepare for mass submission during an interval (2)

Since time of job preparation is strongly affected by the system operational environment (CPU utilization, I/O time etc.) and also by the JES MAS definitions, it is impossible to say, a priori, how the optimal value MULTISUB should be calculated. Nevertheless it is clear that slowly incrementing the MULTISUB value will have a positive performance effect until reaching an optimal (critical) value. Exceeding such an optimal value might cause some performance degradation.

Note that in any case, better performance is always achieved by choosing some value for the MULTISUB parameter rather than relying on its default value.