Application on Virtual Machine runs slower than expected

Products

VMware vSphere ESXi 7.0 VMware vSphere ESXi 8.0

Issue/Introduction

Symptoms:

Virtual Machine application Performance is poor when compared to another Host
Applications run slower than expected. When they are moved to another Host, Performance improves
Virtual Machines encounter higher than expected CPU %Ready times in ESXTOP
Processor Power Management (Power Saving, Power Scaling) is impacting Application Performance on Virtual Machines
vDGA/vSGA Performance is sluggish on View Desktops
Tera2800 Performance is less than expected in a View PCoIP session

Environment

ESXi 7.x

ESXi 8.x

Resolution

Applications which are sensitive to CPU latencies may show less than expected Performance when Processor Power Management features are enabled.

It may be necessary to disable/turn off ESXi/ESX Power Management and Server Hardware Power Management features to achieve the best Performance for these Applications.

Disabling Power Management usually results in more Power being consumed by the System, especially when it is lightly loaded.

The majority of Applications benefit from the Power savings offered by Power Management, with little or no impact on Performance.

Therefore, if disabling of Power Management features does not result in increased Application Performance,

VMware by Broadcom recommends that Power Management features should be re-enabled to reduce Power consumption.

Disabling ESXi/ESX Power Management

The ESXi/ESX Kernel can manage CPU Power usage on supported Hardware whose BIOS settings are configured to allow OS-controlled Power Management.

In this case, you can select from various ESXi/ESX Power Management policies using the vSphere Client Host Configuration panel.

There are four Power Management policies available in ESXi 8.x, 7.x and 6.x:

High Performance ( = This will disable the Power Management )
Balanced (Default)
Low Power
Custom

Remark:

If you see only one Policy (= not supported), then the Hardware either does not support Power Management, or its BIOS settings are configured to disallow OS-controlled Power Management.

In such a case, please reach out to your HW Vendor for any further questions/clarification.

Disabling Hardware Power Management

Disabling Processor Power Management in the Server Hardware is Vendor specific. If assistance is needed, reach out to your Vendor. Following some common server Platforms:

HP ProLiant with the HP Power Profile option (ProLiant G6 or greater)
For HP Power Profile:

Maximum Performance ( = This will disable the Power Management )
Balanced Power and Performance
Minimum Power Usage
Custom (= If already selected, set the HP Power Regulator Mode to OS Control Mode / If already selected, refer to the Power Regulator Mode options below. )

HP ProLiant without the HP Power Profile option
Review the Power Regulator Modes in the BIOS settings:

HP Static High Performance mode ( = This will disable the Power Management )
HP Static Low Power mode
HP Dynamic Power Savings mode
Ultra Low Power Mode ( Only present when selected: HP Static Low Power Mode or HP Dynamic Power Savings Mode, and allows the CPU to transition to its lowest power state.
OS Control mode ( If selected, see the preceding Section for disabling Power Management within the OS )

Dell PowerEdge 11th Generation servers with BIOS
Review the Power Management in the BIOS settings:

Maximum Performance ( = This will disable the Power Management )
Active power control
OS Control ( If selected, set the various Subsystems to OS DBPM and see the Section above for disabling Power Management within the OS )
Custom (If selected, it allows for modification of the CPU Power & Performance, Fan Power & Performance, and Memory Power & Performance Management. If using Custom, set the various subsystems mentioned previously to Maximum Performance )

Dell PowerEdge 12th Generation servers with UEFI
Review the System Profile modes in the System Setup > System BIOS settings:

Performance ( = This will disable the Power Management )
Performance Per Watt (OS) ( If selected, see the Section above for disabling Power Management within the OS )
Performance Per Watt (DAPC-System)
Dense Configuration (DAPC-System)
Custom ( If selected, it allows for modification of the CPU Power Management, Memory Frequency and Turbo Boost (when applicable CPUs are used). If using Custom, set the various Subsystems mentioned previously to Maximum Performance )

Additional Information

Note: It may be necessary to Reboot the Host after changing the Power Management from the vSphere Client.