Job Limiting Services function

Purpose

To provide you with the ability to control the number of jobs of a particular type that can be selected for execution at the same time. The mechanism to control job selection is Limiting Agents. The Job Limiting Services (JLS) commands allow you to override limits that are normally set up in JAL.

Function identifier

JLS

Dependencies

JLS Application

Description of usage

Job Limiting Services provides your installation with the ability to control automatically how many jobs of a particular type can execute concurrently. This is accomplished without having to resort to separate execution classes and their associated initiators.

Limiting is accomplished with Limiting Agents. These Agents, unlike Binding Agents, do not have to be defined and are created during ThruPut Manager JAL processing.

Normally the limits are set in JAL. Operational commands are provided that override JAL settings. This is intended to handle situations where temporary conditions require altering limits.

Additionally, system level limiting lets you set limiting values that apply only to a single system.

Setting upper limit for an agent

A command is provided to set the upper limit for a particular Limiting Agent. Once the limit is set with a command this overrides the JAL limits and continues that way until a explicit JLS RESET command is issued. An example:

This command permanently alters the Limiting Agent AR.DEVELOP to an upper limit of 10 concurrent executing jobs in the MAS complex.

Adjusting limits using relative values

Once set, values for Limiting Agents can be adjusted up or down using a relative value. You can specify the amount to be added to or subtracted from that the Agent's current value. When you make this adjustment, you must also specify both the maximum or minimum value, and also the default value in case the Agent does not currently have a value:

This command adds 5 to the current value for the Agent AR.DEVELOP, then sets it to the new value or 12, whichever is lower. If AR.DEVELOP does not have a value at present, 5 is used, and no relative adjustment occurs.

Resetting limiting agents for JAL values

Once a Limiting Agent has been altered with the JLS SET command, it must be reset with a command to again accept the limits set in JAL. For example:

The limits set in JAL are again operational for the Agent AR.DEVELOP.

Setting and resetting system level limiting agents

System level Limiting Agents impose two levels of limiting:

• System level limits apply only to the system that was specified when they were set. The system level limit defaults to 0 when the Agent is defined, and you must use a JLS SET command to set its value.
• JESplex limits restrict the total of all jobs (weight-adjusted) that can be associated with the Agent across the whole JESplex. The JESplex limit can be assigned when the Agent is defined in JAL.

System level Limiting Agents must have names that begin with a plus sign (+). To set the system level limit for a system:

Since the SYSTEM keyword is used, the system level limit is set to 3 for Agents that begin with the characters '+AGENT' on the named system (SYS1). The system level limit for these Agents on other systems in the JESplex remains at 0.

The JLS RESET command, when issued without the ALL keyword, is designed to "undo" an equivalent JLS SET command. For example, to "undo" the previous JLS SET command:

To "undo" the effects of JLS SET commands in a manner that is independent of the way the commands were issued, you have to use the ALL keyword. If we add the ALL keyword to the command shown above, it looks like this:

In this case, you are requesting that all system level Limiting Agents that have names that start with the letters '+AGENT' be reset regardless of how they were set.

Displaying limiting agents

Display facilities are provided for Limiting Agents. Because these Agents are created dynamically, the display can only show the ones that are in use at any particular time.

For example:

The above command displays all the Limiting Agents that are in use at the time the command is issued.

Several keywords are provided with the JLS DISPLAY command to facilitate operational control.

 Removing a job from JLS control

If necessary, you can remove a job completely from JLS management with the JLS ABANDON command:

This command unconditionally removes the job from JLS control. All Limiting Agents no longer apply to the job.

 JLS command summary