C-Acceptable time considerations
This section explains how the settings in the dialog affect the calculated acceptable time.
In PCS acceptable time is an attribute of a job: it is the wall-clock time and date after which the job is considered late. It differs from the definition used in service groups in two ways:
- The acceptable time for a GS group job refers to the time the job must start by to be "acceptable"; in PCS the acceptable time is the time a job must complete by not to be considered late.
- Jobs in a service group continue to age between the acceptable and critical thresholds; in the PS queue, a PCS job ages to the critical threshold immediately on reaching the acceptable threshold.
Note that the Defaults and Options sub-dialog displays the specified acceptable time; the View/Edit Active Battle Plan panels display the calculated acceptable time.
Acceptable Time is calculated by applying five processes:
- 4. Specification Process
- 5. Inheritance Process, with two wrinkles
- 6. Propagation Process, with a wrinkle for repeating jobs
- 7. Shifting Process
- 8. Relaxed rule process
Specification Process
Acceptable time follows the specification and inheritance process as described in the Defaults and Options Determination with the additional wrinkles and processes described here.
Settings that affect the acceptable time calculation are
- Acceptable Time, with its wrinkles to specify the day
- Day calc. adjustment
- Use Due out Time as Acceptable Time (Y/N),
- Next Production Cycle (Y/N), with the name of Next Production Cycle,
- Starting time of the Production Cycle,
- Ending time of the Production Cycle,
- Shift amount,
- After-Shift Time,
- Repeating group coefficients.
The specification of the acceptable time field has the most direct effect. In general the defaults of the other fields are benign and need not be set except in particular circumstances described here.
Specifying acceptable time
Specifying an acceptable time is not just a time, but a time and day. The initial value is the time and date of the end of the production cycle.
When setting a default for a day-of-week production cycle (L5-L7) the anchor for the acceptable time is the starting time of the production cycle and the values for same day, next day and second next day are interpreted within this context. So:
- Same day= same date as the production cycle starting time.
- Next day= date of the next day after the production cycle starts.
- 2nd next day= date of the second next day after the production cycle starts.
For instance production cycles that start at 1 minute after midnight (of say Monday) could prevail up to 72 hours (until 11:59 pm Wednesday). Production cycles that start at 1 minute to midnight (i.e. still on Sunday) could prevail up to 48 hours (until 11:58 pm Tuesday).
PCS prevents you from specifying an acceptable time earlier than the start of the production cycle.
When a setting is for $All-PCs (L1-L4), the starting time of each production cycle may not be the same. In this case the Implied Day concept is used. The implied day is determined by finding the first occurrence of the acceptable time after the anchor for this entity occurs. When setting the acceptable time for an application (L2), the anchor is the production cycle start time. When setting the acceptable time for a job tree (L3), the anchor is the expected submission time to the request queue of the header job of the tree. When setting the acceptable time for a job (L4), the anchor is the expected submission time to the request queue of the job.
Thus when Implied Day is used it could resolve differently on different days. With implied day concept the same time entered may occur on different implied days. For example, say the production cycle starts at 10 am on Monday and 11:15 am on Tuesday, and the acceptable time for the FUL application is set to 11:00 am (for all production cycles). On Monday the FUL application is considered late if it runs past 11 am Monday; on Tuesday the FUL application is considered late if it runs past 11 am Wednesday.
The Day Calc. Adjustment field addresses this issue. It alters the anchor value explained above to be earlier by this field value. This is helpful for short running jobs that start and complete shortly after a production cycle starts, or when the production cycle time differs day-to-day by a few minutes. Without this adjustment some jobs might be shifted into the next day when they should be in the current day.
Thus if we have to restart a battle plan (and therefore a production cycle), we could inadvertently change acceptable times of some jobs, especially if we specify the production cycle as "now to end of original production cycle".
The specification of the other fields related to acceptable time calculation, listed earlier, are covered in the following sections.
Inheritance Process
The inheritance process for acceptable time follows the inheritance process described in Defaults and Options Determination with three additional wrinkles: Use Due-out time as acceptable, Next Production Cycle, and Repeating Groups.
Use Due out as Acceptable Value
The Use CA 7 DUE-OUT as Acc. field has a Y or N value. When Y and a CA 7 due out time is specified in the CA 7 database, the acceptable time is populated with the due out time value. When N the due out time is ignored with respect to acceptable time.
Since values from both Acceptable Time field and the Use CA 7 DUE-OUT field can be inherited, the one at the most specific level prevails. When they are both specified at the same level, the due-out time value is used.
Next Production Cycle
When long running trees creep into the next production cycle, defaults and options, including acceptable time, may be set on the wrong day. For instance, knowing a job runs on Tuesday, you might update the Tuesday battle plan with a new acceptable time value, when, in fact, the job is part of a long running tree from the Monday battle plan.
This feature directs PCS to look for settings at the L8 level (i.e., a specific job) in the next production cycle and apply them to the job in the current production cycle if there isn't an L8 setting there already.
To use this feature, see Next Production Cycle section.
Repeating Groups
Repeating jobs inherit the acceptable time just like any other job; their accommodation is in the propagation process, described below, based on the inherited value.
Propagation Process
For acceptable time, the inheritance process (as described above) is followed by a propagation process: using the expected start time and expected elapse time, PCS starts at each trailer job and travels the triggering and predecessor relationships calculating the time the upstream job must complete by for the downstream job to complete by its acceptable time. If the calculated time is earlier than the upstream job's current acceptable time, it is changed to the calculated time. This process is repeated whenever an field that affects acceptable time is updated.
Repeating Groups
The normal propagation process occurs within a repeating group. In addition, each instance of the group gets its own acceptable time, as a whole. PCS automatically uses the correct strategy: one for when a group completes before the next begins, and one for when the groups are expected to overlap.
Shifting Process
The acceptable time can be further modified by the shifting process. Here all the acceptable times of any jobs belonging to an application in a active battle plan are increased or decreased by the same amount. This is reflected on the display panels as positive or negative value under the Shf column, beside the acceptable time column.
The shift can be overridden for particular jobs with the original value or a new value by setting the After-Shift Time.
Shifts over a production cycle boundary, whether backwards over the start boundary or forward over an end boundary do not trigger the relaxed fit rule, described in the next section.
For the details to specify the shifted value and After shift values, see Shift Definition of lateness temporarily.
The Shf and After-Shift Time persist for the battle plan they are specified in. They are not carried over to the next battle plan. If any job persists into the next battle plan it reverts to their unshifted acceptable time value, and any After Shift Time values are ignored. If necessary the shift can be re-specified in the new battle plan.
Relaxed Fit Process
The relaxed fit rule applies when the acceptable time for a job is inherited as "the end of the production cycle" (i.e., no acceptable time at any level was specified for it), and the production cycle ends before the job is completed. Thus the relaxed rule can apply to trailer jobs only. In this case PCS "relaxes" the acceptable time of the trailer job such that the rerun factor for the uncompleted path has a rerun factor of 1.