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Power10 Performance Best Practices

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
     
 

Additional Information

Best Practices documents and References:
Power:
Advisor Tools:
• VIOS Advisor
Redbooks:

Document Location

Worldwide

Operating System

AIX:All operating systems listed

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Document Information

Modified date:
17 February 2024

UID

ibm17038687

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