HiperDispatch Details workspace

This workspace provides HiperDispatch-related topology and utilization statistics at the LPAR and individual logical processor level for an LPAR on which an OMEGAMON XE on z/OS agent is running, if the LPAR is in HiperDispatch mode. This information can help you determine how your HiperDispatch configuration is performing.

The HiperDispatch feature, which is available on System z10 and above, makes efficient use of CPU-level hardware caching, by dispatching of work, where possible, on the same physical CPU or another CPU on the same book, to take advantage of cache hits in L1, L1.5, or local L2 caches.

HiperDispatch Management at the z/OS image level can be deployed on one or more of the LPARs in a complex. HiperDispatch is activated for an LPAR by specifying HiperDispatch=YES in the SYS1.PARMLIB IEAOPT member. If HiperDispatch=NO (the default), physical CPUs are assigned equally across all of the logical CPUs in an LPAR.

For HiperDispatch information to be available, the following conditions must be in effect:

If these conditions are in effect, the Workload Manager (WLM) can determine if the LPAR should be in HiperDispatch mode or not. If there is sufficient work in this LPAR to keep 1.5 physical CPUs busy, WLM places the LPAR in HiperDispatch mode. If demand falls below this threshold, WLM takes the LPAR out of HiperDispatch mode.

Two views present information at the LPAR level:

When HiperDispatch Management is on, three additional views display the logical CPU ID, entitlement (High, Medium or Low), percentage entitlement, physical CPU percentage, physical overhead percentage managing the CPU within the LPAR, and a status (Online, Offline, Parked, Park Pending, or Reserved) for each CPU, by logical type.

In analyzing the performance of an LPAR in HiperDispatch-mode, two views of CPU resource consumption are important: the LPAR view of CPU consumption and the z/OS view of CPU consumption. The LPAR view evaluates how much physical CPU resource is being consumed of the LPAR's share of the total Central Processing Complex (CPC). The z/OS view of the CPU consumption takes into account the parked time of each CPU when calculating the CPU Busy Percentage. Parked Time is the time which discretionary CPU resources (Low share processors) in an LPAR spend not being considered for CPU dispatching. A resulting high value percentage is usually indicative of latent demand from the LPAR, an important indicator for performance analysis purposes. Additionally, the percentage of time during a reporting interval that the CPU was parked is displayed (MVS Busy Percentage) and the reporting also provides the LPAR-wide LPAR Busy Percentage and MVS Busy percentages.

You can link to this workspace from a row in the System CPU Utilization workspace.

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