Monitoring zIIP Usage

This document provides information on how to view and control data on zIIP processing.

See also Monitoring the Cache Usage in the section Print and Work File Caching.

zIIP Processing Reports Available

You can use the Natural system command ZIIP to determine whether the current Natural session is running on a zIIP and analyze your CPU time savings by zIIP enablement.

The ZIIP command displays the number of GCPs and zIIPs available in the your z/OS environment, the CPU time consumed and, optionally, a list of components that caused SRB/TCB switches: see the example reports and explanations in zIIP Processing Information and zIIP Component Switch Statistics in the System Commands documentation.

For batch processing, you can also set the keyword subparameter PRINT of the profile parameter ZIIP to print zIIP processing information automatically at the end of the session.

A report with general zIIP information and component switch statistics is also printed when your CICS or Com-plete environment is shut down, depending on the version of the Natural CICS Interface or Natural Com-plete/SMARTS Interface, respectively, installed at your site. This report is similar to the report produced by the PRINT option of the ZIIP system command. For a CICS environment, the required program definitions are described in the section Natural zIIP Shutdown Statistics in Installing Natural CICS Interface in the Installation for z/OS documentation.

Determining the Number of zIIPs Available

If you do not know how many zIIPs are available in your z/OS LPARs (logical partitions), you can check this with the following operator command:


The following example result of this command shows that four GCPs (00 to 03) and one zIIP (+I) is running in the current LPAR, and that one additional GCP (05) and one additional zIIP (-I) are defined as spare processors.

IEE174I 12.39.09 DISPLAY M 781
ID CPU                   SERIAL
00 +                      0FA10E2098
01 +                      0FA10E2098
02 +                      0FA10E2098
03 +                      0FA10E2098
04 +I                     0FA10E2098
05 -
06 -I

Using SDSF ENC to Watch zIIP Usage

If you have the z/OS SDSF (System Display and Search Facility) installed under TSO, you can use the command ENC to obtain information about all WLM enclaves currently active in your z/OS environment and their zIIP usage.

For detailed information, see the IBM literature SDSF Operation and Customization.

Calculating the CPU Time

Be aware that in the SDSF "D A" display the CPU time does not show the real values if running in a WLM enclave. You need to use the value of "ECPU Time" to evaluate the right CPU usage of your zIIP-enabled Natural session. The following definitions are quoted from the IBM z/OS SDSF documentation:

  • "CPU Time" is the CPU time (TCB + SRB) for the address space, excluding any NP-SRB/enclave time.

  • "ECPU Time" is the CPU time (TCB + SRB) for the address space, plus any NP-SRB/enclave time; that is, CPU used on behalf of this address space - the SDSF definition of "CPU Time".

Com-plete UQ A and Natural ISPF only document the "CPU Time", there is no "ECPU Time" value available.

Evaluating the z/OS SMF Type 30 Records

You can evaluate the SMF type 30 records to obtain statistics about zIIP processing per address space. These records contain several fields with various job step CPU time values such as TCB, SRB, WLM enclave and zIIP times.

For detailed information, see the IBM literature z/OS MVS System Management Facilities (SMF).