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  • CICS Transaction Server for z/OSVersion 4 Release 2

    Performance Guide

    SC34-7177-02

    IBM

  • CICS Transaction Server for z/OSVersion 4 Release 2

    Performance Guide

    SC34-7177-02

    IBM

  • NoteBefore using this information and the product it supports, read the information in Notices on page 921.

    This edition applies to Version 4 Release 2 of CICS Transaction Server for z/OS (product number 5655-S97) and toall subsequent releases and modifications until otherwise indicated in new editions.

    Copyright IBM Corporation 1983, 2014.US Government Users Restricted Rights Use, duplication or disclosure restricted by GSA ADP Schedule Contractwith IBM Corp.

  • Contents

    Preface . . . . . . . . . . . . . . . xiWhat this book is about . . . . . . . . . . xi

    Who this book is for . . . . . . . . . . xiWhat you need to know to understand this book xiHow to use this book . . . . . . . . . . xiNotes on terminology . . . . . . . . . . xi

    Changes in CICS Transaction Serverfor z/OS, Version 4 Release 2 . . . . . xiii

    Part 1. Measuring, tuning, andmonitoring: the basics . . . . . . . 1

    Chapter 1. Performance monitoring andreview . . . . . . . . . . . . . . . 3Establishing monitoring activities and techniques . . 3Planning your monitoring schedule. . . . . . . 5Typical performance review questions . . . . . . 7CICS performance analysis techniques . . . . . 10

    What to investigate when analyzing performance 11Establishing a measurement and evaluation plan 13Assessing the performance of your system . . . 14Methods of performance analysis . . . . . . 15Performance analysis: Full-load measurement . . 16Performance analysis: Single-transactionmeasurement . . . . . . . . . . . . . 19

    Chapter 2. Performance measurementtools. . . . . . . . . . . . . . . . 21Tuning your system . . . . . . . . . . . 22CICS provided tools for obtaining performance data 24

    System management facility (SMF) . . . . . 25Generalized trace facility (GTF) . . . . . . . 25CICS Performance Analyzer for z/OS (CICS PA) 27

    Other tools for obtaining performance data . . . . 32Resource measurement facility (RMF). . . . . 33IMS provided tools for obtaining performancedata . . . . . . . . . . . . . . . . 35TCP/IP monitoring . . . . . . . . . . . 35Tivoli Decision Support for z/OS . . . . . . 36Tivoli OMEGAMON XE for CICS on z/OS . . . 48OMEGAMON XE for DB2 . . . . . . . . 48

    Chapter 3. Identifying CICSperformance constraints . . . . . . . 51Hardware contentions . . . . . . . . . . . 51Design considerations . . . . . . . . . . . 52Observing response time . . . . . . . . . . 53

    Poor response time: Causes and solutions . . . 55Reducing storage stress . . . . . . . . . . 56Reducing DASD paging activity . . . . . . . 58Reducing resource contention . . . . . . . . 59Resolving resource problems . . . . . . . . 60

    Reducing storage violations . . . . . . . . . 62

    Part 2. Improving the performanceof a CICS system . . . . . . . . . 63

    Chapter 4. CICS Transaction Manager:performance and tuning . . . . . . . 67Setting the maximum task specification (MXT) . . 67Using transaction classes (MAXACTIVE) to controltransactions . . . . . . . . . . . . . . 68Specifying a transaction class purge threshold(PURGETHRESH) . . . . . . . . . . . . 68Prioritizing tasks . . . . . . . . . . . . 70

    Chapter 5. CICS dispatcher:performance and tuning . . . . . . . 73System initialization parameters for open TCBs . . 73

    Open TCB pools . . . . . . . . . . . . 75Interval control value parameters: ICV, ICVR, andICVTSD . . . . . . . . . . . . . . . 79MROBTCH . . . . . . . . . . . . . . 80FORCEQR . . . . . . . . . . . . . . . 80SUBTSKS . . . . . . . . . . . . . . . 81PRTYAGE . . . . . . . . . . . . . . . 82Interpreting dispatcher statistics . . . . . . . 82

    TCB statistics . . . . . . . . . . . . . 82Dispatcher TCB Pool statistics and JVMs . . . 84

    Chapter 6. Virtual and real storage:performance and tuning . . . . . . . 85CICS virtual storage . . . . . . . . . . . 85

    CICS region size . . . . . . . . . . . . 87CICS dynamic storage areas . . . . . . . . 88Setting the limits for CICS storage . . . . . . 94Short-on-storage conditions in dynamic storageareas . . . . . . . . . . . . . . . 104CICS subpools . . . . . . . . . . . . 110CICS kernel storage . . . . . . . . . . 12864-bit MVS storage . . . . . . . . . . 129MVS storage below 2 GB . . . . . . . . 130

    Splitting online systems: virtual storage . . . . 137Using modules in the link pack area (LPA/ELPA) 138Selecting aligned or unaligned maps . . . . . 139Defining programs as resident, nonresident, ortransient . . . . . . . . . . . . . . . 140Putting application programs above 16 MB . . . 141Allocation of real storage when using transactionisolation . . . . . . . . . . . . . . . 141Limiting the expansion of subpool 229 using SNApacing. . . . . . . . . . . . . . . . 142

    Copyright IBM Corp. 1983, 2014 iii

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  • Chapter 7. CICS storage protectionfacilities: Performance and tuning . . 145

    Chapter 8. Tuning with LanguageEnvironment . . . . . . . . . . . . 147Minimizing GETMAIN and FREEMAIN activity 147

    AUTODST: Language Environment automaticstorage tuning . . . . . . . . . . . . 147RUWAPOOL: Run-unit work area pools . . . 148

    Language Environment run time options forAMODE (24) programs . . . . . . . . . . 148Using DLLs in C++ . . . . . . . . . . . 149Minimizing the time Language Environmentspends writing dump output to transient dataqueue CESE . . . . . . . . . . . . . . 149

    Chapter 9. Java applications:performance and tuning . . . . . . . 151

    Chapter 10. MVS and DASD:performance and tuning . . . . . . . 153Performance management . . . . . . . . . 154Performance management: useful links . . . . . 155

    Chapter 11. Networking and the z/OSCommunications Server: performanceand tuning . . . . . . . . . . . . 157Setting the size of the terminal input and outputarea . . . . . . . . . . . . . . . . 157Setting the size of the receive-any input areas . . 159Setting the size of the receive-any pool . . . . . 160Using the MVS high performance option with SNA 162Adjusting the number of transmissions in SNAtransaction flows . . . . . . . . . . . . 163Using SNA chaining to segment large messages 164Limiting the number of concurrent logon andlogoff requests . . . . . . . . . . . . . 165Adjusting the terminal scan delay . . . . . . 166Compressing output terminal data streams . . . 169Tuning automatic installation of terminals . . . . 170

    Chapter 12. CICS MRO, ISC and IPIC:performance and tuning . . . . . . . 173Managing queues for intersystems sessions . . . 176

    Relevant statistics . . . . . . . . . . . 177Ways of approaching the problem andrecommendations . . . . . . . . . . . 178Monitoring the settings . . . . . . . . . 178

    Using transaction classes DFHTCLSX andDFHTCLQ2 to control storage use . . . . . . 179Controlling the length of the terminal input/outputarea (SESSIONS IOAREALEN) for MRO sessions . 179Batching requests (MROBTCH) . . . . . . . 180Extending the life of mirror transactions(MROLRM and MROFSE) . . . . . . . . . 181Controlling the deletion of shipped terminaldefinitions (DSHIPINT and DSHIPIDL) . . . . 182

    Limitations . . . . . . . . . . . . . 183

    Recommendations . . . . . . . . . . . 183

    Chapter 13. CICS VSAM and filecontrol: Performance and tuning . . . 185VSAM tuning: General objectives. . . . . . . 185

    Local shared resources (LSR) or nonsharedresources (NSR) . . . . . . . . . . . 185

    Using VSAM subtasking. . . . . . . . . . 197Using data tables . . . . . . . . . . . . 199Using coupling facility data tables . . . . . . 201

    Coupling facility data table statistics. . . . . 205Local shared resources (LSR) or nonsharedresources (NSR) . . . . . . . . . . . 206Coupling facility data tables . . . . . . . 212

    Using VSAM record-level sharing . . . . . . 213Threadsafe file control applications . . . . . . 216File control API costs . . . . . . . . . . . 217

    Chapter 14. Database management forperformance . . . . . . . . . . . . 221Setting DBCTL parameters . . . . . . . . . 221Tuning the CICS DB2 attachment facility . . . . 221Selecting authorization IDs for performance andmaintenance. . . . . . . . . . . . . . 222Logging . . . . . . . . . . . . . . . 224Sync pointing . . . . . . . . . . . . . 225

    Chapter 15. CICS logging andjournaling: Performance and tuning. . 227The CICS log manager . . . . . . . . . . 227Log stream storage . . . . . . . . . . . 228Journal records . . . . . . . . . . . . . 230Monitoring the logger environment . . . . . . 231Writing data to the coupling facility: Performanceconsiderations . . . . . . . . . . . . . 232Defining the number of log streams: Performanceconsiderations . . . . . . . . . . . . . 233

    Element/entry ratio and the number of logstreams per structure . . . . . . . . . . 234Dynamic repartitioning and the frequency ofDASD offloading . . . . . . . . . . . 234

    LOWOFFLOAD and HIGHOFFLOAD parameterson log stream definition . . . . . . . . . . 235Tuning the size of staging data sets . . . . . . 237The activity keypoint frequency (AKPFREQ) . . . 238

    AKPFREQ and MRO . . . . . . . . . . 239The log defer interval (LGDFINT) . . . . . . 239DASD-only logging . . . . . . . . . . . 240

    Chapter 16. CICS temporary storage:Performance and tuning. . . . . . . 243CICS temporary storage: overview . . . . . . 244Automatic deletion of temporary storage queues 245Main temporary storage: monitoring and tuning 246Auxiliary temporary storage: monitoring andtuning . . . . . . . . . . . . . . . . 248Recoverable and nonrecoverable TS queues . . . 249

    iv CICS TS for z/OS 4.2: Performance Guide

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  • Chapter 17. CICS transient data (TD)facility: Performance and tuning

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