Selecting WLM assistance policies

When you have decided that a job should be considered as critical, HCL Workload Automation for Z allows you to choose between different assistance policies. To activate a particular policy, you have to specify the code that identifies it in the POLICY field on the JOB, WTO, AND PRINT OPTIONS panel (accessible from either the APPLICATION DESCRIPTION or MODIFYING THE CURRENT PLAN panel). If you do not specify a policy for a particular critical job, HCL Workload Automation for Z applies either the common policy specified in the WLM statement of OPCOPTS or the default common policy (if one has not been specified). Valid assistance policy codes are:

L

Long Duration. When a critical job runs over the expected duration (as specified by the user), it is promoted to a higher-performance class by the scheduler. This policy is activated by specifying the letter L in the Assist Policy field on the APPLICATION DESCRIPTION panel.

Note: The resources are used also when not necessary, but for a short interval.

D

Deadline. When a critical job runs over its real deadline (calculated as Latest Start Time + Duration), it is promoted to a higher-performance class by the scheduler.

Note: This policy is always recommended when the S(mart) policy is not used. The resources are used only when strictly necessary, but it might be too late.

S

Latest Start Time. When a critical job starts after its latest start time, it is promoted to a higher-performance class by the scheduler.

Note: The resources are used also when not strictly necessary, but it can prevent delayed termination of jobs.

C

Conditional. The assistance policy is a smart compromise between the Deadline and the Latest Start Time policies as follows:

HCL Workload Automation for Z checks if the conditions of the Deadline policy are met and promotes the job.
If the conditions of the Deadline policy are not met, the promotion is immediate for jobs started with a significant delay with respect to the remaining time to deadline. The time to deadline can have different weights according to the Threshold value that you specify in the WLM statement of OPCOPTS. The default value is 20%. If you specify a value of 0%, the Latest Start Time policy is automatically applied in this second step. If you specify a value of 100%, the Latest Start Time policy is applied only when the time from the Latest Start Time is greater than that remaining to the deadline.

If a different policy is not specified in the WLM statement, this is the policy that HCL Workload Automation for Z uses as a common policy.

Note: This policy is always recommended, but it requires additional tuning efforts for correct setting of the Threshold value.

The advantages and disadvantages of the assistance policies are:

Table 1. Advantages and disadvantages of assistance policies
Assistance Policy (Intervention Option)	Advantages	Disadvantages
Duration	Gentle smoothing Low impact	Possibility of intervention when not actually necessary Limited gain
Deadline	Gentle smoothing Low impact 100% certainty that intervention is required	Limited gain
Latest Start Time	High gain High probability that intervention is required	High risk of overcompensating
Conditional	Best action taken for every situation No decision necessary by you	Tuning efforts to set the Threshold value

The Workstation Analyzer checks for late operations every two minutes. When it discovers a late operation that is critical, there might be additional two minutes delay before the WLM action is taken (for example, to promote the job to the service class).