zIIP enabled in IDMS but DCPROFIL shows 0 zIIP Engines

Products

• IDMS
• IDMS - Database

Issue/Introduction

IDMS zIIP processing is enabled but on the DCPROFIL task shows:

zIIP ENGINES:          0000

Is there anything else needed to enable zIIP in IDMS?

Environment

Release: All supported releases.

Cause

DCPROFIL will always show the number of zIIP processors available even when zIIP processing is turned off in IDMS. If the number of zIIP processors is 0 it means there are no zIIP processors online. Ensure that at least one zIIP processor is online for IDMS to make use of it. To check the status of processors use the z/OS console command: 

DISPLAY M=CPU

This will show the status of general and zIIP processors:

General processors online will be marked with a +
zIIP processors online will be marked with a +I
General processors offline will be marked with a -
zIIP processors offline will be marked with a -I

Resolution

If the zIIP processors are offline in the operating system, configure them to be online.

To enable the use of zIIP processors in IDMS, specify zIIP=Y in the PARM statement of the JCL when starting IDMS.

After the CV is up, use command DCMT VARY ZIIP ON/OFF to enable/disable zIIP.

In addition, some modules need to be loaded form an APF authorized library. The list of modules is documented in the section titled zIIP Eligibility.

The easiest way to implement this is to APF authorize the whole CAGJLOAD library. Note that not every load library in the STEPLIB and CDMSLIB need to be authorized. Only the libraries containing the nucleus modules. 

Once zIIP processors are online and zIIP is activated in IDMS, DCPROFIL will display:

TAPE: CAGJJ0 OPERATING SYSTEM: z/OS ZIIP=Y 

zIIP ENGINES: 0001

Note that ZIIP is of more benefit on CVs that more execute system code, mostly ERUS processing.

There is less benefit if there is a lot of user written code executed, ADS, COBOL, Assembler, see How to know if zIIP is beneficial for an IDMS CV.

If after applying the PTFs, performance with zIIP is not good then it means the workload is not suited to the use of zIIP.

Additional Information

The requirements for using zIIP in IDMS are documented in the section zIIP Exploitation.