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CICS Tools Identify Performance Issues

CICS

This article focuses on CICS performance. On the mainframe CICS is known as CICS Transaction Server (TS), but on other platforms the product is named TXSeries, and for special functions, CICS Transaction Gateway. All products are developed and supported by CICS development, and are designed to interact with each other via facilities such as CICS Intercommunication. While techniques, methodology, syntax, parameters and implementation specifics may vary, most functions, concepts and usage apply to all processing platforms. Thus, the term “CICS” in this article applies to both CICS TS and TXSeries unless otherwise stated.

It’s easy to determine if a performance issue exists in an IT system: Depress the Enter/Send key, click the mouse on a selection or tap an icon and wait. And wait some more. Maybe even more. Or watch a video start and stop, blank out and return, instead of playing smoothly. Or submit a report job and wait a couple days for it to appear on your desk or print out on your printer. Performance problems are very easy to detect. Determining what performance degradations exist and why they occur is another matter.

Identifying performance inefficiencies and related causes can be confounding, partly because there’s so much complexity, many components that could fail, detection facilities don’t exist or are turned off and there’s interdependence between components. For example, inadequate real storage can consume processor utilization by causing excessive paging, leading to a conclusion there’s insufficient processing capacity. Yet the real solution lies in adding real storage, which reduces CPU utilization and OS waits (due to time spent reading pages into the processor).

So determining the causes of performance degradation are often convoluted and obscure. Getting to the bottom of performance deficiency requires data describing various performance metrics and the ability to monitor systems in real-time. Further compounding matters is that, in most cases CICS is competing with other processing, so data collection needs to occur on both a system and CICS level. In the past, each product (e.g., CICS, MVS, IMS, etc.) recorded its own performance data, but over time SMF evolved to gather all this information and store it files or using the MVS System Logger, standardizing the process.

Because performance data is now recorded in a documented and architected way, tools and internal mechanisms can exploit the data to produce tabular reports, graphical representations and other useful depictions. Analysis techniques like trending, interval analysis, queuing theory, interval plotting and other data-massaging techniques can turn raw data into a treasure-trove of guidance on how to optimize processing resources. Products from IBM and other vendors provide this capability, and additionally provide extensive performance monitoring capabilities that allow an analyst to keep a finger on a system’s pulse. CICS has produced a wide variety of tools, functions and components that are consistent between CICS TS and TXSeries.

Mainframe Recording and Storing Performance Information

SMF isn’t a component of CICS; instead it’s a component of z/OS, but CICS does use SMF to write performance, audit and accounting records to SMF files named SYS1.MAN1 and SYS1.MAN2, or alternatively, MVS Logstreams. In most cases, SMF will already be set up and operational, but should that not be the case, here in a nutshell are the steps required to enable and activate it:

  • Review installation materials and MVS System Management Facilities (SMF)
  • Set up SMF datasets or MVS Logstreams
  • Create SYS1.PARMLIB member SMFPRMxx with LSNAME parameters specifying record types of interest, using test suffix
  • Determine dumping options and procedures
  • Tailor SMF to meet your system requirements
  • Test SMF via IPL and console commands
  • Review SMF file contents for veracity
    • Most z/OS components, features and supporting products (e.g., CICS TS, DB2, etc.) produce SMF records
    • Each record has an 18 or 24 byte header containing record type, optional subtype, date and timestamp
    • Record Types 00-127 are IBM products, Types 128-255 are user records
    • CICS creates Type 110 records, Types 42 and 92 are dataset activity, Types 30, 70-79 are CPU, paging and I/O activity
  • Review SMF data using RMF, Omegamon or other reporting and analysis tool

For more information, see MVS System Management Facilities (SMF)

Jim Schesvold is a technical editor for IBM Systems Magazine. Jim can be reached at jschesvold@mainframehelp.com.



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