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DCMT DISPLAY SUBTASK Command Usage

DCMT DISPLAY SUBTASK

Displays the following information for the specified subtask or for each subtask:

Field

Value

Name

The name of each subtask

Number

The number of each subtask

Status

The current status of the subtask (IDLE or BUSY)

Work type

One of the following types of work the subtask can execute:

  • I or IDMS—Database and communication work
  • R or RRS—RRS (Resource Recovery System) work

Count wakeups

The number of times DC/UCF restarted this subtask.

Count task dispatches

The number of times DC/UCF dispatched this subtask.

User mode CPU time

The amount of time this subtask spent in user-mode execution.

System mode CPU time

The amount of time this subtask spent in system-mode execution.

CPU effectiveness (%)

The percentage comparison of CPU time to wall clock time while the subtask was executing. A subtask is considered to be executing if it has not been put into a WAIT state by the CA IDMS system. An executing subtask can lose effective CPU time due to paging or to other tasks being given a higher priority by the operating system.

Count times fast posted

The number of times the IDMS postexit was able to post an ECB without requiring a call to the operating system while running on this subtask.

Count times 0S posted

The number of times the operating system's post SVC was used to post an ECB. This field should always be zero unless operating sytem PC routines are not available.

Count found work pass 1

The number of times the IDMS dispatcher found work queued to the global dispatch work queue (CSAWKQUE) while using this subtask.

Count found work pass 2

The number of times the IDMS dispatcher found work to dispatch while scanning the DCE active chain using this subtask.

Count times POSTEXIT resumed

The number of times the operating system woke the IDMS system up through its PCRESUME routine using this subtask.

DCMT DISPLAY SUBTASK 000n

(z/OS systems only) Displays the following CPU statistics under Enclave Info when zIIP support is active:

Field

Value

zIIP time

The CPU time consumed while physically executing on a zIIP processor.

zIIP on CP time

The CPU time used on a CP, such as the time ofscheduling the zIIP processor use and contention for a zIIP processor.

CPU effectiveness

The percentage comparison of CPU time to wall-clock time while the subtask was executing. A subtask is considered to be executing if it has not been put into a WAIT state by the CA IDMS system. An executing subtask can lose effective CPU time due to paging or to other tasks being given a higher priority by the operating system. Reported CPU effectiveness can exceed 100% due to pro-rating techniques used by the operating system to compensate for relative speed differences between the CP and zIIP.

DCMT DISPLAY SUBTASK EFFECTIVENESS

Displays whether zIIP support is active by subtask and displays the following fields for each TCB and SRB:

Field

Value

Name

The name of each subtask.

Elapsed time

The length of time the subtask or SRB has been running.

Total CPU time

The amount of CPU time the subtask or SRB has used.

CPU effectiveness

The percentage comparison of CPU time to wall-clock time while the subtask was executing. A subtask is considered to be executing if it has not been put into a WAIT state by the CA IDMS system. An executing subtask can lose effective CPU time due to paging or to other tasks being given a higher priority by the operating system. Reported CPU effectiveness can exceed 100% due to pro-rating techniques used by the operating system to compensate for relative speed differences between the CP and zIIP.

Subtask Naming Convention

The first subtask that DC/UCF allocates is named MAINTASK. Subsequently allocated subtasks are used only with multitasking or when RRS support is activated. They have names configured as follows:

SUBTnnnn

The first subtask allocated after MAINTASK is SUBT0001, the second SUBT0002, and so forth.

Subtask Numbering Conventions

When DC/UCF allocates subtasks for a given it gives each subtask a number. MAINTASK is always subtask 1 (0001), the next subtask that's allocated is number 2, and so forth.

The total number of subtasks on the system is determined at system startup time, in the startup JCL.

When DC/UCF Restarts Subtasks

To reduce overhead, DC/UCF only restarts (wakes up) an operating system subtask when DC/UCF tasks are queued for the next associated system service. When this happens, DC/UCF assigns the next task that requests the queued service to an idle subtask.

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