Configuring IBM Z Integrated Information Processor (zIIP) specialty engines for Db2

Portions of certain Db2 processing are eligible for dispatching, as implemented by IBM Z Integrated Information Processor (zIIP) specialty engines.

Before you begin

See the z/OS® information about planning for, configuring, and using zIIP engines in Using System z Integrated Information Processor (zIIP).

About this task

How much you can reduce general-purpose processor use varies based on the amount of workload executed by the zIIP specialty engine, among other factors. You must ensure that sufficient IBM Z Integrated Information Processor (zIIP) capacity is available to the LPAR where Db2 runs to maximize zIIPoffload, and support latency requirements.

Procedure

  1. Understand the processes that are authorized for dispatching to zIIP specialty engines, as described in Authorized zIIP uses for Db2 processing.
  2. Consider whether to enable work in the zIIP queue to be re-dispatched to a GCP when there is delay for zIIP specialty engines, as described in The zIIP needs help function and Db2.
  3. Be aware of and evaluate the following limitations for tasks that run on zIIP:
    • Blocked workload support, which provides the means to promote CPU starved workloads, is not enabled for zIIP specialty engines.
    • The zIIP "needs help" function (IIPHONORPRIORITY = YES) can get delayed in a zIIP-constrained environment.
    • Work classified as Discretionary to WLM does not benefit from the zIIP “needs help” function.
  4. Ensure sufficient zIIP capacity for the LPAR where Db2 runs, as described in Configuring zIIP capacity for Db2 workloads.

What to do next

Monitor zIIP use as described in Monitoring zIIP and zAAP specialty engine use for Db2.