Virtual machine application runs slower than expected in ESXi

Products

• VMware vSphere ESXi

Issue/Introduction

To increase the virtual machine application performance, disable the power management.

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

VMware vSphere ESXi 8.x

VMware vSphere ESXi 7.x

 

Resolution

Poor performance may be related to processor power management implemented either by ESXi/ESX or by the server hardware. Certain applications that are very sensitive to processing speed latencies may show less than expected performance when processor power management features are enabled. It may be necessary to turn off ESXi/ESX and server hardware power management features to achieve the best performance for such 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 performance impact. Therefore, if disabling power management does not realize any increased performance, VMware recommends that power management be re-enabled to reduce power consumption.
 

Disabling ESXi/ESX Power Management

The ESXi/ESX kernel can manage processor 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
• Balanced (Default)
• Low Power
• Custom

Choose High Performance to disable power management.

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.

 

Disabling Hardware Power Management

Disabling processor power management in the server hardware is vendor specific. Here are some common server platforms:

• HP ProLiant servers with the HP Power Profile option (ProLiant G6 or greater)
  
  Review both the HP Power Profile and HP Power Regulator Mode in the BIOS settings. For HP Power Profile, you see these options:
   
  • Balanced Power and Performance
  • Minimum Power Usage
  • Maximum Performance
  • Custom
  
  Choose Maximum Performance to disable power management. If Custom is already selected, refer to the Power Regulator Mode options below. If you choose Custom, set the HP Power Regulator Mode to OS Control Mode.
   
• HP ProLiant servers without the HP Power Profile option
  
  Review the Power Regulator Modes in the BIOS settings. You see these options:
   
  • HP Static High Performance mode
  • HP Static Low Power mode
  • HP Dynamic Power Savings mode
  • OS Control mode
  • Ultra Low Power Mode
  
  Choose HP Static High Performance mode to disable power management. If OS Control mode is selected, see the preceding section for disabling power management within the OS.
  
  Note: Some HP BIOS settings may include an option called Ultra Low Power Mode. This only applies in HP Static Low Power Mode or HP Dynamic Power Savings Mode, and allows the CPU to transition to its lowest power state.
   
• Dell PowerEdge 11th Generation servers with BIOS
  
  Review the Power Management in the BIOS settings. You see these options:
   
  • OS Control
  • Active power control
  • Custom
  • Maximum Performance
  
  Choose Maximum Performance to disable power management. If Custom is selected, this allows for modification of the CPU Power and Performance, Fan Power and Performance, and Memory Power and Performance Management. If using Custom, set the various subsystems mentioned previously to Maximum Performance. If OS Control mode is selected, set the various subsystems to OS DBPM and see the section above for disabling power management within the OS.
   
• Dell PowerEdge 12th Generation servers with UEFI
  
  Review the System Profile modes in the System Setup > System BIOS settings. You see these options:
   
  • Performance Per Watt (DAPC-System)
  • Performance Per Watt (OS)
  • Performance
  • Dense Configuration (DAPC-System)
  • Custom
  
  Choose Performance to disable power management. If Custom is selected, this 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. If you choose Performance Per Watt (OS), see the section above for disabling power management within the OS.
  
  Note: Some Dell UEFI settings may include an option called Dense Configuration (DAPC-System). For more information on this setting, see 

Note: If you require further help locating these options in the BIOS, please involve your Hardware vendor.

 

Additional Information

Note: It may be necessary to reboot the host after changing the power management from the vSphere Client.