Workload consolidation

Tuning to reduce the number of simultaneously active address spaces to the proper number that are needed to support a workload can reduce relative nest intensity (RNI) and improve performance.

This effect is described in Relative nest intensity.

Combined with improvements in earlier releases, the following areas in CICS® TS 5.1 enable you to run more work through fewer CICS regions than ever before:

• Increase in the concurrent task limit

  Changes to the MXT system initialization parameter, which now permits a maximum of 2000 tasks in a CICS region concurrently, are described in Changes to system initialization parameters: CICS TS V5.1.

• Virtual storage constraint relief

  The reduction in CICS 24-bit and 31-bit storage usage, as described in Virtual storage constraint relief: CICS TS V5.1, for CICS TS 5.1 enables more concurrent tasks in a single CICS region.

• Threadsafe support

  Changes in CICS, as described in Improvements in threadsafety, can reduce contention for the QR TCB. Workloads that were formerly constrained by the single QR TCB can now be able to run concurrently on an open TCB.

The process of workload consolidation involves reducing the number of CICS regions while maintaining the same level of availability, reliability, and throughput. The remainder of this section describes two performance studies that demonstrate how workload consolidation can reduce CPU usage, real storage usage, and operational costs because of requiring management of fewer CICS address spaces while maintaining the same transaction throughput.