How To
Summary
Power10 Performance Best Practices
Objective
This document is intended as a short summary for customers on key items that should be looked at using Power10 hardware. For a more in-depth and more complete set of recommendations, please refer to the links provided.
Environment
Power10
Steps
Recommendations:
- Ensure firmware is current
Fix Central provides latest updates. Install the latest version of FW1010 for the Power10 E1080 1-node or 2-node servers. Use the Fix Level Recommendation Tool (FLRT) tool to obtain the recommended levels.
NOTE: Ensure required HMC level is installed when updating firmware.
- Ensure OS level is current
Fix Central provides the latest updates for AIX, IBM i, VIOS, Linux, HMC and F/W. In addition to that, the FLRT tool provides the recommended levels for each hardware model. Use these tools to maintain your system levels.
- Memory DIMMs
Follow proper memory plug-in rules.
These can be found here.
- Partition placement
Current firmware levels ensure optimal placement of the partitions. However, if numerous DLPAR operations are executed on partitions on the CEC, it is recommended the use Dynamic Partition Optimizer (DPO) to optimize placement (requires current level of firmware).
- NX GZIP
To take advantage of NX GZIP H/W accelerator on Power10 processor-based systems.
- IBM i
Ensure Technology Updates are current.
These can be found here.
- VIOS configuration
• VIOS 3.1.3 runs on Power10 compatibility mode. Shared Ethernet adapters using a 10Gb, 40Gb or 100Gb Mellanox adapter as a backing device.
• Enable the “flip_n_run” attribute, via chdev, on the network adapter port:
chdev ent# -a flip_n_run=yes
• Do not enable CPU folding.
• If configured with shared processors assign total entitlement of all VIOS partitions to be 10-15% of cores in shared pool and assign CPU ratio of 2:1 (vCPUs:ec). Refer to the PowerVM Best Practices for additional recommendations and assign uncapped mode and set variable weight capacity of VIOS partition higher than all client LPARs serviced by VIOS.
• For performance and flexibility, it is recommended to use IBM i to virtualize internal storage to IBM i. If you do want to use VIOS, then follow the wiki at the following link.
• For vFC, ensure the number of client connections does not exceed the limits of the physical adapter.
• For vSCSI disks, ensure the queue_depth for virtual disks is less than or equal the queue_depth of the physical disk in the VIOS.
• For vSCSI adapters, ensure you cnfigure VTDs based on the following formula: Max VTDs = (512 -2) / (virtual_q_depth + 3)
- Sizing a system
When migrating to Power10, we recommend considering using SMT8, and size the LPARs based on the SMT8 rPerf values; in many instances, this will likely reduce the number of VPs required.
- Right-size your Shared LPARs
• Assign entitled capacity (EC) to sustained peak utilization for LPARs with critical SLA requirement.
• Assign EC to average utilization and number of virtual CPUs to peak utilization (physical core consumption) for LPARs with non-critical SLA.
• Ensure the average LPAR utilization is equal or less than 75% of the entitled capacity.
- 100GbE adapter
RHEL8.4: For network bandwidth sensitive workloads, we recommend increase the receive queue
size from 1024 to 4096 and increase the number of combined queues to 64.
AIX 7.3: For network bandwidth sensitive workloads, we recommend increase the receive queue size
from 1024 to 4096, increase the number of receive queues to 20 and transmit queues to 12
- vNIC
• AIX - Change the following vNIC interface settings as follows:
chdev -l ent# -a rx_que_num=16 -a tx_que_num=16 -a rx_que_elem=2048 -a tx_que_elem=1024 -a use_rec_q_val=no
• Linux distros - Update to latest kernel. Also, set rx/tx queues to maximum:
ethtool -L eth# rx 16 tx 16
- Virtual Ethernet adapters on AIX
Increase the virtual Ethernet (vETH) device driver buffers if the partition is dropping packets on the virtual interface even when running with entitled CPU capacity. e.g.
# chdev –l ent# -a max_buf_xxx=NNNN
- Live Partition Mobility (LPM)
Use of 10Gb or faster dedicated network for Live Partition Mobility (LPM) is preferred. - Compilers
Take advantage of new Power10 ISA features for operating systems running in Power10 mode by using the following compiler releases or later:
• IBM Open XL C/C++ for AIX and XL C/C++ for AIX documentation library
• IBM Open XL Fortran for AIX and XL Fortran for AIX documentation library
• IBM Advance Toolchain for Linux on Power
• More information on compiler versions may be found here - Java
Java applications can seamlessly take advantage of new Power10 ISA features on operating systems running in Power10 mode by using the Java runtime versions listed below or newer:- Java 8
IBM SDK 8 SR6 FP36
IBM Semeru Runtime Open Edition 8u302: openj9-0.27.1 - Java11
IBM Semeru Runtime Certified Edition 11.0.12.1: openj9-0.27.1
IBM Semeru Runtime Open Edition 11.0.12.1: openj9-0.27.1 - Java17
IBM Semeru Runtime Certified Edition 17: openj9-0.28
IBM Semeru Runtime Open Edition 17: openj9-0.28
- Java 8
- AIX Tunables
• Tuning a VIOS is not recommended unless directed by VIOS/AIX support.
• Restricted tunables should not be modified (unless directed by AIX/VIOS development).
• Tunables should be at default unless otherwise recommended by AIX support.
• If tunables have been modified from default, they should be re-evaluated prior to moving to a different processor platform.
- AIX CPU utilization
The AIX operating system is optimized for best raw throughput at higher CPU usage when running with dedicated processors. When running with shared processors, the AIX OS system is optimized to reduce CPU usage (pc column in vmstat). If there is a requirement to reduce CPU usage (pc), use the schedo tunable vpm_throughput_mode to tune the workload and evaluate the benefits of raw throughput vs. CPU usage.
Additional Information
Best Practices documents and References:
Power:
• Power Virtualization Best Practices
• IBM Power Systems Performance Report (Enhanced rPerf)
• Power10 (and Power9) Migration hints and tips
• IBM Power Systems Performance Report (Enhanced rPerf)
• Power10 (and Power9) Migration hints and tips
IBM i
• IBM i on Power – Performance FAQ
• IBM i on Power – Performance FAQ
AIX and VIOS
• AIX Service Strategy and Best Practices
• AIX Service Strategy and Best Practices
Databases
• Modernizing Oracle Database on IBM Power
• Modernizing Oracle Database on IBM Power
Advisor Tools:
• VIOS Advisor
• VIOS Advisor
Redbooks:
Document Location
Worldwide
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Document Information
Modified date:
17 February 2024
UID
ibm17038687