User Guide

IBM

Power

Virtual Processors

• The sum of the entitled cores of all shared partitions cannot exceed the number of cores in the shared pool

• Ensure number of configured virtual processors of any shared partitions on a frame is not more than number of cores in the shared pool

• Configure the number of virtual processors for a shared partition to sustained peak capacity demand

• Configure the number of entitled cores for a shared partition to average utilization of that partition for better performance

• To ensure better memory and CPU affinity (avoid unnecessary preemptions of the virtual processor), ensure the sum of the entitled cores of all

shared partitions close to the number of the cores in the shared pool

Processor Compatibility Mode

• There are 2 processor compatibility mode available for AIX: POWER9 and POWER9_base. Default is POWER9_base mode.

• There are 2 processor compatibility mode available for Linux: POWER9 and POWER10 mode. Default is POWER10 mode.

• After LPM partitions, need to power cycle when changing processor compatibility mode

Processor Folding Considerations

• For share partition running AIX on Power9, the default vpm_throughput_mode = 0, on Power10, the default vpm_throughput_mode = 2. For

workloads have long running jobs, it can potentially help with core usage reduction.

• For dedicated partition running AIX, the default vpm_throughput_mode = 0 on both Power9 and Power10.

LPAR Page Table Size Considerations

• Radix page table is supported starting on Power10 running Linux. It can potentially improve workload performance.

Reference:

Hints andTips for Migrating Workload to IBM POWER Systems

•

https://www.ibm.com/downloads/cas/39XWR7YM

IBM POWERVirtualizationBest PracticesGuide

• https://www.ibm.com/downloads/cas/JVGZA8RW

Power10 Quick Start Guide - PowerVM Best Practices