Assigning jobs to the appropriate processor and address space for C/I service

If you have defined C/I FSS address spaces, two installation exits let you control where jobs get processed through C/I service. If you have defined C/I FSS address spaces on local processors, remember that C/I processing of jobs might take place on a local processor. Also, remember that in a complex having processors with different release levels of MVS™ or different JCL definitions, jobs may use JCL parameters or statements that require conversion, interpretation, and execution on a particular system. You must ensure that JES3 routes those jobs to the proper system.

Before the job enters C/I processing, you can use installation exit IATUX46 to examine and limit the processors eligible for selection for the job's C/I processing. You can also specify whether the JES3 global address space is eligible. You can use installation exit IATUX49 to override JES3's choice of address space (and, thus, the processor) for the job's C/I processing. For detailed information on the installation exit routines, see z/OS JES3 Customization.

You may also influence JES3's decision as to where to schedule C/I processing by the CIDEMAND (for demand select jobs) and CIBATCH (for batch jobs) initialization parameters on the CLASS or STANDARDS initialization statements. You may use these parameters to indicate that jobs of a certain class or all jobs must have C/I processing performed where the job's class is enabled or where the job is eligible to run.

Within the limits imposed by installation exits IATUX46, IATUX49, and the CIDEMAND and CIBATCH initialization parameters, JES3 schedules jobs to a CI DSP using a priority scheme that considers whether jobs are batch or demand select jobs.

JES3 schedules demand select jobs to demand select CI DSPs in the following priority:
  1. In the JES3 global address space.
  2. In any C/I FSS on the global, provided that the job can execute on the global.
  3. In any C/I FSS on a local, provided that the job can execute on the selected local.
  4. In any C/I FSS on the global, regardless of whether the job can execute on the global.
  5. In any C/I FSS on a local, regardless of whether the job can execute on the selected local.
Note: If more than one C/I FSS is active, JES3 selects the FSS with the greatest number of available demand select CI DSPs.
JES3 attempts to schedule batch jobs to batch CI DSPs in the following priority:
  1. In any C/I FSS on the global, provided that the job can execute on the global.
  2. In any C/I FSS on a local, provided that the job can execute on the selected local.
  3. In any C/I FSS on the global, regardless of whether the job can execute on the global.
  4. In any C/I FSS on a local, regardless of whether the job can execute on the selected local.
  5. In the JES3 global address space.
Note:
  1. If more than one C/I FSS is active, JES3 selects the FSS with the greatest number of available batch CI DSPs.
  2. Either the SYSTEM or SYSAFF parameter on the JOB control statement, or the SYSTEM parameter on the //*MAIN control statement, is considered for CI scheduling purposes when determining where the job is eligible to run. The job's scheduling environment does not apply.
Parent topic: Controlling Jobs Through C/I Service