Benchmarking tests indicate slow memory performance in a virtual machine

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Benchmarking tests indicate that memory performance in a virtual machine is slower than expected.
• Virtual machine memory performance is not being impacted by any application of memory limits or host memory over-commitment.

Environment

VMware vSphere ESXi 5.1
VMware vSphere ESXi 5.0
VMware ESXi 4.0.x Embedded
VMware ESX 4.0.x
VMware vSphere ESXi 5.5
VMware ESX 4.1.x
VMware ESXi 4.0.x Installable
VMware ESXi 4.1.x Embedded
VMware ESXi 4.1.x Installable

Cause

This issue may occur because it is necessary that the ESXi host and the virtual machine both use hardware assisted memory virtualization features to obtain optimal memory performance in a virtual machine.

Resolution

To resolve this issue, verify that:

• The CPU on ESXi host supports Intel Extended Page Tables (EPT) or AMD Rapid Virtualization Indexing (RVI) hardware virtualization.
• The virtual machine settings are configured to use hardware memory management unit (MMU).
  
• Confirm that hardware MMU is in use by checking the /vmfs/volumes/datastore/virtual_machine/vmware.log for one of these messages:
  
  
  • YYYY-MM-DDT10:17:45.923Z| vmx| I120: HV Settings: virtual exec = 'hardware'; virtual mmu = 'hardware'
  • 2015-10-09T07:04:36.434Z| vmx| HV Settings: virtual exec = 'hardware'; virtual mmu = 'hardware'
  • 2015-03-15T22:00:47.045Z| vmx| I120: HV Settings: virtual exec = 'hardware'; virtual mmu = 'hardware'
    
    Note: If it is necessary to change monitor mode, see Changing the virtual machine monitor mode (1036775)
    
    Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.
    
    
• Ensure that the ESXi host BIOS is up-to-date, which is required to ensure that EPT/RVI functions correctly.

Additional Information

For more information, see A Comparison of Software and Hardware Techniques for x86 Virtualization.
Changing the virtual machine monitor mode
ベンチマークテストで、仮想マシン内のメモリパフォーマンスが悪い結果になる