IntelliMagic Vision release 10.1.0 expands the Connectivity Topology View to the area of LPARs.
In a z/OS sysplex decisions made during the LPAR configuration process influence the physical processor share that each logical processor has. Having an optimal processor configuration will result in optimizing processor and cache usage. More work will be done with fewer processor cycles. Optimizing the processor and cache usage is important for optimizing the CPU costs. IntelliMagic Vision’s Topology Viewer will help the z/OS systems manager with this task.
Topology Viewer
IntelliMagic Vision release 9.25.0 introduced the Topology Viewer for Disk Configuration Connectivity in July 2020. Now IntelliMagic Vision release 10.1.0 expands the Topology Viewer capabilities to the area of LPAR Topology. PR/SM dynamically assigns logical CPs on each LPAR to hardware chips, nodes, and drawers, seeking to optimize cache efficiency. This LPAR topology can have a very significant impact on processor CPU efficiency. Remote cache accesses can take hundreds of machine cycles. SMF 99.14 records are produced every 5 minutes and capture drawer/node/chip location data for each logical CP. The new visualization of LPAR Topology data makes this data far easier to analyze and interpret.
Example of IntelliMagic Vision’s LPAR Topology View
IntelliMagic Vision will initially show a complete topology diagram (see image below). This contains all logical CPs defined to this LPAR. It combines physical resources beginning from the CEC with logical resources beginning from the sysplex. The LPAR Topology View certainly contains a lot of important information. In this form it is easy to understand.
The primary focus of processor cache analysis is typically on general purpose CPs. That CPU generates the software expense. A common way to use this view shown above is to select any CP and drilldown. The “CP only” view pictured below makes it immediately apparent that all the Vertical High logical CPs for this LPAR are colocated on a single physical chip. This is the ideal situation for processor cache efficiency.
When looking at the LPAR topology, it is important to realize that the processor assignments may change frequently. The topology may well be different during the peak day online time frame compared to the evening batch time frame.
For more information see also John Ticic’s blog.
Related resources
Tracking Processor Topology Changes Over Time
Processor topology can change over time, so there is a need to verify changes and understand any impact that may be the result of those changes.
Using Interactive z/OS Topology Views to Optimize Processor Configuration
Being able to easily see, filter, compare, and interact with the processor topology enables analysts to easily configure their processor configuration, which is important for reducing CPU cost.
Real World Experiences with z16 Upgrades
In this reprint from Cheryl Watson’s Tuning Letter, Todd Havekost provides detailed information and insights from his analysis of seven upgrades from both z14 and z15 CPCs to z16s.