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.
The hyperthreaded core sharing option must be enabled in your system's BIOS settings. For more information, see the Resource Management documentation.
Power off the virtual machine.
- In the vSphere Client inventory, right-click the virtual machine and select Edit Settings.
- Click the Resources tab and select Advanced CPU.
- Select a mode from the Hyperthreading Sharing Mode drop-down menu.
The virtual CPUs of this virtual machine can share cores with other virtual CPUs of this or other virtual machines.
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.
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.
- Click OK to save your changes.