To increase performance, you can select how the virtual CPUs of a virtual machine share physical cores on a hyperthreaded system.

Hyperthreading technology allows a single physical processor to behave like two logical processors. The hyperthreaded core sharing option provides detailed control over whether to schedule a virtual machine to share a physical processor core. The processor can run two independent applications at the same time. Although hyperthreading does not double the performance of a system, it can increase performance by better utilizing idle resources.

ESXi generally manages processor scheduling well, even when hyperthreading is enabled. These settings are useful only for detailed tweaking of critical virtual machines.

The hyperthreaded core sharing option must be enabled in your system's BIOS settings. See the vSphere Resource Management documentation.

Turn off the virtual machine.

1

Right-click the virtual machine and select Edit Settings.

a

To locate a virtual machine, select a datacenter, folder, cluster, resource pool, host, or vApp.

b

Click the Related Objects tab and click Virtual Machines.

2

On the Virtual Hardware tab, expand CPU, and select a sharing mode from the HT Sharing drop-down menu.

Option

Description

Any (default)

The virtual CPUs of this virtual machine can share cores with other virtual CPUs of this or other virtual machines.

None

The virtual CPUs of this virtual machine have exclusive use of a processor core whenever they are scheduled to it. The other hyperthread of the core is halted while this virtual machine is using the core.

Internal

On a virtual machine with exactly two virtual processors, the two virtual processors are allowed to share one physical core (at the discretion of the host scheduler), but this virtual machine never shares a core with any other virtual machine. If this virtual machine has any other number of processors other than two, this setting is the same as the None setting.

3

Click OK.