HyperThreading and VM Performance Relationship in vSphere ESXi Environment

[DCYun]

Please answer about hyperthreading and vsphere esxi performance.

When hyperthreading is enabled, the number of logical processes is doubled.
(A system with one 8-core CPU be the 16 logical processes.)

When creating a VM that requires 4 cores ( physically 4 cores ),
what is the good way to create VM ?

Allocate 4 vCPUs ? or allocate over 4 vCPUs in consideration of hyper-threading?

[vbondzio · Accepted solution]

From 6.7 onward, 4 vCPUs and a full CPU reservation (# of vCPUs * nominal frequency of the underlying CPU). For highly latency sensitive applications or for 6.5 and earlier, enable Latency Sensitivity = High + a full CPU reservation. Note that the latter means that nothing else can use 4 cores of the host, even if the VM is completely idle.