The TSO Component of CPExpert

(Applies only to Compatibility Mode)

IBM's Time Sharing Option (TSO) became available in 1969 as an option with the Multiprogramming with a Variable Number of Tasks (MVT) operating system.

Neither IBM nor the user community appreciated the extent to which TSO would be used.

TSO has gained unexpected acceptance as a test and production tool in MVS installations. There are few MVS installations without a significant TSO user community, ranging from systems programmers, to operations monitors, to application developers, to end users.

TSO response time often is the significant metric by which the efficiency of an installation is gauged. From the perspective of a TSO user, installation performance is often based on how well TSO responds to user interactions.

There are several commercially-available tools which report TSO response times. Unfortunately, most of the problems with TSO performance are not caused by TSO.

Most TSO response problems are caused by the interaction between TSO and MVS, caused by the interaction between TSO and the rest of the system, or caused by other workload on the system.

The TSO Component of CPExpert analyzes TSO response times, and analyzes the interaction between TSO and the environment in which it executes.

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

When using the TSO Component, you specify your TSO response objectives (for example, you might specify that the average TSO Period 1 response should be less than one-half second).

You might also wish to analyze TSO response problems only during certain times (for example, you might be concerned only with the Prime Shift).

The TSO Component analyzes standard SMF/RMF data (contained in your MXG or MICS) performance data base) to identify intervals in which TSO response did not meet your response objectives.

The TSO Component performs a detailed analysis of SMF/RMF data for any period in which TSO response is found to be unacceptable.

The TSO Component "decomposes" the TSO response time into the major areas which could delay a TSO transaction, and determines the likely causes of the problems. The TSO Component analyzes TSO response problems from the perspective of MVS, the System Resources Manager, the paging subsystem, and the overall system configuration.

The following are typical causes of poor TSO response time detected by the TSO Component of CPExpert:
Swap-in delayed TSO users. 
TSO users were denied access to a processor because of system overhead. 
TSO users were denied access to a processor because of workload with a higher dispatching priority. 
Excessive paging delayed TSO users. 
Waiting for I/O to complete delayed TSO users. 
Inappropriate SRM parameters delayed TSO users (especially the parameters controlling domain contention index computations). 
Contention with other work in the system delayed TSO users. 
Contention for system resources among TSO users caused response delays. 
Inadequate processor power delayed TSO users.


When the TSO Component discovers that a particular problem accounts for a significant amount of the TSO response time, a detailed analysis is performed of the problem area. The TSO Component then provides suggestions about how to correct the problem.

The SRM Component of CPExpert is required for the TSO Component to execute. This is because the SRM Component processes SYS1.PARMLIB members and builds SAS data sets to describe the specifications.

The TSO Component reads these SAS data sets to build a model of your computer environment from the perspective of the System Resources Manager. Using this model, CPExpert can determine domain structures, dispatching priorities, etc. as it analyzes potential constraints to improved TSO performance.

Many installations specify different IEAICS/IEAIPS combinations for different operations shifts. You can specify any combination of IEAICS/IEAIPS members to CPExpert and CPExpert will build SAS data sets for each combination.

When analyzing data contained in your MXG or MICS performance data base, CPExpert examines information in SMF Type 72 records to identify the correct IEAICSxx/IEAIPSxx/IEAOPTxx combination. CPExpert dynamically selects the correct SYS1.PARMLIB information to guide its analysis of system performance.

The TSO Component User Manual provides a detailed description of each finding. The documentation includes an indication of what impact the finding would normally have, discusses why the finding was made (including a discussion of the MVS logic and operation involved), and suggests alternative ways to correct the potential problem.

Sample "rule" description from the TSO Component User Manual.

The TSO Component of CPExpert is not applicable to MVS Goal Mode. With Goal Mode, the functions of the TSO Component have been incorporated into the WLM Component of CPExpert.

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Last updated by Don Deese on 06/15/2001.