Determine if zIIP is beneficial for an IDMS CV

Products

• IDMS
• IDMS - Database

Issue/Introduction

This document describes how to know if zIIP is of benefit to a particular CV.

Using the zIIP feature may not be beneficial to every IDMS CV. The more user written code a CV executes (ADS, cobol, assembler), the less likely a CV is to benefit from using zIIP. The more system code a CV executes (mostly ERUS processing), the more likely a CV is to benefit from zIIP.

Environment

Release: All supported releases.

Resolution

The simplest way to determine if zIIP is beneficial for a CV is to determine the total amount of TCB CPU time per task. If that figure decreases when zIIP is enabled, then it is of benefit to that CV.

Using DCMT D SUBT EFF and DCMT D STA SYS, calculate this figure. The attached Word document shows examples of this with and without zIIP. The green shaded figures are the statistics used in the calculation. The red number is the final result.

Note that the final statistic "with zIIP" (0.002755) is lower than that "without zIIP" (0.002964). Therefore, this CV is benefiting from using zIIP.

Additional Information

zIIP Exploitation
Evaluating the zIIP feature benefits