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.
- Understand the processes that are authorized for dispatching to zIIP specialty engines, as described in Authorized zIIP uses for Db2 processing.
- 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.
- 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.
- Ensure sufficient zIIP capacity for the LPAR where Db2 runs, as described in Configuring zIIP capacity for Db2 workloads.