CICS monitoring facility: performance considerations

The CICS® monitoring facility collects data about the performance of all user- and CICS-supplied transactions during online processing for later offline analysis. The records produced by CICS monitoring are of the MVS™ System Management type 110, and are written to an SMF data set.

Monitoring data is useful for performance, tuning, and for charging your users for the resources they use. See The CICS monitoring facility for further information.

Limitations

Performance class monitoring can be a significant overhead. The overhead is likely to be about 5 to 10%, but is dependent on the workload.

Recommendations

If you do not need accounting information because other billing processes exist and you have other means of gathering any performance data required, the CICS monitoring facility should not be used. The same is true for the exception component.

Recording of the above information incurs overhead, but, to tune a system, both performance and exception information may be required. If this is not a daily process, the CICS monitoring facility may not need to be run all the time. When tuning, it is necessary to run the CICS monitoring facility during peak volume times because this is when performance problems occur.

Consider excluding fields from monitoring records if overuse of the SMF data set is a potential problem.

How implemented

To implement CICS monitoring, you can reset the system initialization table parameters (MNPER, MNEXC, and MN)--see the CICS System Definition Guide.

You can change the settings dynamically using either CEMT INQUIRE|SET MONITOR or EXEC CICS INQUIRE|SET MONITOR. See Controlling CICS monitoring for more information. Alternatively see dfha700l; for details of CEMT, and the CICS System Programming Reference manual for programming information about INQUIRE and SET commands.

For further information about using the CICS monitoring facility, see The CICS monitoring facility.

How monitored

CICS Monitoring Domain statistics show the number of records produced of each type. These statistics monitor CMF activity.

MVS address space or RMF™ data can be gathered whether or not the CICS monitoring facility is active to give an indication of the performance overhead incurred when using the CICS monitoring facility.

Related tasks
CICS facilities: performance considerations
Tuning the use of CICS temporary storage (TS)
Using temporary storage data sharing to improve performance
Optimizing the performance of the CICS transient data (TD) facility
Using Global ENQ/DEQ to improve performance
CICS trace: performance considerations
CICS recovery: performance considerations
CICS security: performance considerations
CICS storage protection facilities: performance considerations
CICS business transaction services: performance considerations
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