Virtual Hyperthreading support for VMs

Virtual Hyperthreading (vHT) is supported for VMs.

In vSphere 8.0, vHT is supported for VMs. vHT is deactivated by default and can be activated under the latency sensitivity settings for each VM. vHT supports a maximum HT size of 2.

vHT is an extension of latency sensitivity high feature. Applications which benefit from hyperthreading awareness can see performance improvements with latency sensitivity high and vHT activated. The performance gain might come from sufficient resource reservation and that the VM has exclusive physical CPUs.

Without vHT activated on ESXi, each virtual CPU (vCPU) is equivalent to a single non-hyperthreaded core available to the guest operating system. With vHT activated, each guest vCPU is treated as a single hyperthread of a virtual core (vCore).

Virtual hyperthreads of the same vCore occupy the same physical core. As a result, vCPUs of the VM can share the same core as opposed to using multiple cores on VMs with latency sensitivity high that have vHT deactivated.

ESXi hosts and VM running older hardware versions cannot use this feature.