Chapter 32: Further Reading - Performance Tuning for COBOL Programs

Books

"Enterprise COBOL for z/OS: Performance Tuning" by IBM Redbooks This Redbook is dedicated entirely to COBOL performance optimization on z/OS. It covers compiler option selection with benchmark data showing the CPU impact of each option, working storage layout optimization, efficient I/O patterns, and DB2 access path tuning. The benchmarks comparing different coding techniques (COMP vs. COMP-3 vs. DISPLAY, SEARCH vs. SEARCH ALL, PERFORM vs. inline code) are backed by actual measurements on current hardware, making this the most data-driven COBOL performance resource available.

"DB2 for z/OS: Application Programming and SQL Guide -- Performance Considerations" by IBM The performance chapters of the DB2 Application Programming Guide provide detailed guidance on writing efficient SQL in COBOL programs. Topics include predicate classification (stage 1 vs. stage 2), index design for query workloads, EXPLAIN interpretation, lock avoidance techniques, and the effective use of OPTIMIZE FOR and FETCH FIRST clauses. This is essential reading for any COBOL developer writing DB2 applications.

"z/OS Performance: Monitoring and Tuning" by Jim Horne and Frank Kyne (IBM Redbooks) A comprehensive guide to z/OS system-level performance monitoring that helps COBOL developers understand the metrics that affect their programs. Chapters cover SMF record analysis, RMF reporting, workload management (WLM) policies, and the interaction between application workloads and system resources. Understanding system-level performance helps developers identify whether a performance problem is in their code, the database, or the system infrastructure.

Online Resources

IBM Developer: COBOL Performance Best Practices IBM's developer portal maintains a collection of COBOL performance articles and code samples demonstrating efficient coding techniques. The resources include side-by-side comparisons of different coding approaches with CPU consumption measurements, guidance on compiler option selection for different program types, and migration guides for moving from older to newer compiler releases that offer performance improvements.

SHARE Conference: COBOL and z/OS Performance Sessions SHARE conferences regularly feature sessions on COBOL performance optimization delivered by IBM compiler developers, performance specialists, and experienced practitioners. Topics include the impact of new compiler features on performance, CICS and DB2 tuning techniques specific to COBOL programs, and case studies showing real-world performance improvement projects with measured results.

Micro Focus: COBOL Performance Optimization for Distributed Platforms While this chapter focused on z/OS, many COBOL performance principles apply across platforms. Micro Focus provides performance tuning documentation for their COBOL runtime environments on Linux, Windows, and cloud platforms. Comparing mainframe and distributed performance considerations helps developers who work in hybrid environments or are migrating workloads between platforms.

IBM Documentation

"Enterprise COBOL for z/OS: Performance Tuning Guide" (GC27-8851) The official IBM performance tuning guide for Enterprise COBOL. This manual documents the performance implications of every compiler option, provides detailed guidance on efficient coding patterns for arithmetic, string handling, table processing, and I/O, and includes a comprehensive checklist for production performance optimization. It is the first resource to consult when tuning a COBOL program.

"z/OS MVS System Management Facilities (SMF)" (SA38-0667) SMF records are the primary source of performance measurement data on z/OS. This manual documents every SMF record type, including type 30 (job/step resource accounting), type 42 (SMS statistics), and type 101/102 (DB2 accounting). Understanding how to interpret SMF data is essential for measuring the impact of performance tuning changes.

"IBM Application Performance Analyzer for z/OS: User's Guide" (SC27-5599) APA (formerly Strobe) is the standard tool for COBOL statement-level CPU profiling. This guide covers how to set up measurement sessions, interpret the results, identify CPU-intensive code paths, and translate findings into specific code or configuration changes. APA's ability to show CPU time by COBOL paragraph and statement makes it indispensable for targeted performance optimization.

Standards and Practices

"Mainframe Performance Engineering: Capacity Planning and Workload Management" Resources on mainframe capacity planning explain how performance tuning relates to overall system capacity management. Understanding workload management (WLM) service classes, performance indexes, and capacity planning methodologies helps COBOL developers set realistic performance targets and understand the constraints within which their programs operate.

"CICS Performance Series" by IBM (Various Publications) IBM publishes a series of performance guides specific to CICS, covering transaction response time analysis, CICS dispatcher tuning, DB2 connection optimization, and BMS performance. For COBOL developers writing CICS applications, these guides provide the CICS-specific performance knowledge that complements general COBOL optimization techniques covered in this chapter.

"The Art of Computer Systems Performance Analysis" by Raj Jain This academic text provides the statistical and analytical foundations for performance measurement and tuning. Topics include workload characterization, performance metrics, experimental design for benchmarks, and statistical analysis of performance data. While not mainframe-specific, the methodologies apply directly to the systematic performance tuning of COBOL applications, helping developers move beyond intuition to evidence-based optimization.