System z Integrated Information Processor (zIIP)

There are many workloads which are zIIP eligible! To assist in planning for zIIP, components of z/OS have been enhanced to report both projected zIIP usage and actual zIIP usage.

The projected usage function (PROJECTCPU) is intended to gather information about how much CPU time is spent executing code which could potentially execute on zIIPs. This information can be gathered from production workloads or from representative workloads to understand the potential for zIIP execution with current applications.

Setting the IEAOPTxx parmlib member option PROJECTCPU=YES directs z/OS to record the amount of work eligible for zIIP [and zAAP] processors. SMF Record Type 72 subtype 3 is input to the RMF post processor. The Workload Activity Report lists workloads by WLM service class. In this report the field APPL% IIPPCP indicates which percentage of an processor is zIIP eligible, (while the field APPL% AAPCP indicates which percentage of an processor is zAAP eligible). SMF Record Type 30 provides more detail on specific address spaces. Because the price of zIIP and zAAP specialty processors is less than that of general purpose processors, values as little as 25% for APPL% AAPCP or AAPL% IIPCP can make a new zAAP or zIIP processor worth your while.

For customers that have installed zIIPs, the reporting functions can provide current zIIP execution information that can be used for optimizing current configurations or for helping to predict potential future usage.

The usage and projected usage monitoring functions are only available on z/OS V1.6 or higher with the appropriate service APARs installed. For more information about which APARs to install, refer to the Program Director for IBM System z9 Integrated Information Processor Support for z/OS V1R6/R7 and z/OS.e V1R6/R7 Web Deliverable, and to the appropriate zIIP PSP buckets.

PROJECTCPU usage and monitoring function support for zIIP is integrated in the base of z/OS V1.8.

To assist in planning for zIIP Assisted IPSec, please see the technical papers on the under Resources for basic sizing guidance for your workload.