WLM Component of CPExpert


In 1994, IBM began delivering the Workload Manager as a part of the new MVS/ESA SP5.1 operating system release.  The Workload Manager provides a radical departure from earlier IBM operating system software. With the Workload Manager, users no longer provide detailed instructions to the System Resources Manager about how to process work. Instead, users partition their workload into service classes, and specify performance goals for each service class.

In 1995, the WLM Component of CPExpert was introduced, to analyze performance aspects of MVS environments running under IBM’s Workload Manager.

The WLM Component analyzes data recorded in standard SMF records (and placed into a performance data base, by MXG® or NeuMICS™ ). The SMF data is analyzed to:

Detect problems with your Workload Manager Service Definition.
Analyze how well the Workload Manager meets performance goals.
Identify the reasons performance goals were not achieved.
Suggest alternatives you can implement to improve performance.

The WLM Component also evaluates overall system areas:

In September 2004, IBM released z/OS V1R6. z/OS V1R6 on z890 and z990 servers supports a new type of processor called the zSeries Application Assist Processor (zAAP).

In October 2004, Release 14.2 of CPExpert was issued to support z/OS V1R6 and to analyze performance aspects of zAAP. This new CPExpert software analyzes:

• Performance of Java service class periods using zAAP, to identify performance problems and the causes of poor performance.

• Incompatibility between performance goals and goal importance specified for Java work using zAAP versus other work running on your system.

• Java applications use of central processors versus use of zAAP. 

• Effective use of new IEAOPTxx parameter specifications that support Java processing on central processors versus zAAP. 

In September 2006, IBM released z/OS V1R8. z/OS V1R8 on System z9 supports another new type of processor called the System z9 Integrated Information Processor (zIIP).

In October 2006, Release 16.2 of CPExpert was issued to support z/OS V1R8 and to analyze performance aspects of zIIP. This new CPExpert software analyzes:

• Performance of DB2 service class periods using zIIP, to identify performance problems and the causes of poor performance.

• Incompatibility between performance goals and goal importance specified for DB2 work using zIIP versus other work running on your system.

• DB2 applications use of central processors versus use of zIIP.   

 

The WLM Component analyzes your coupling facility parameters and system configuration, and suggests ways to improve the performance of your parallel sysplex.
 
The WLM Component analyzes your paging subsystem, and suggests changes to improve system performance.
 
The WLM Component analyzes System Logger, to identify performance problems that often cause significant system overhead.

The WLM Component is normally executed each day, as a final step in the daily update of your performance data base. 

For those performance analysts who have a good grasp of Workload Manager concepts, constraints, and analysis techniques, the WLM Component can significantly reduce the time required to perform daily analysis of system performance.

Since only problem situations are reported by the WLM Component, performance analysts can focus on problems and not waste time analyzing nonproductive areas.

Users typically find that a number of problems are initially identified by CPExpert. These problems usually are resolved within a fairly short time. If the problems cannot be resolved (for example, because of "political" realities), the guidance provided to CPExpert usually is changed.

The result is that during normal day-to-day operation, the WLM Component should provide an indication of a problem only if the problem is "new" - that is, the system or workload changes and a new problem is encountered or has a more significant impact on the performance of service classes.

The WLM Component User Manual provides a detailed description of each finding, and suggests alternative ways to correct the potential problem. The User Manual provides comprehensive documentation about Workload Manager concepts, algorithms, and operational features.

CPExpert is continually enhanced, with updates every 6 months. These updates provide support for new releases of IBM operating systems and provide additional analysis of performance problems.

 

Sample output from the WLM Component.

Sample "rule" description from the WLM Component User Manual.
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Last updated by Don Deese on 11/07/06.