Cpu overcommitment with multiple cpu guests


Dear forum,

The RedHat virtualisation docs about overcommitting resources say that overcommitting cpu’s works best when the guests only have one virtual cpu each.

It also says that a guest should not have more virtual cpu’s than there are cores on the host, which makes sense.

I have tried and failed to find some discussion, information, recommendations or measurements relating to intermediate cases, where guests each have multiple cpu’s that are less than the number of cores on the host, but the total number of virtual cpu’s is more than the number of cores on the host. Does anyone have any experience or know of any information relating to cases like this? For example, how well would a host with 8 cores support 8 KVM virtual machines each configured with 2 virtual cpu’s, as compared to 16 virtual machines with 1 virtual cpu each? If this kind of setup can be made to work well, are there any specific configuration items that are useful for this kind of situation?

Thanks for any information and pointers,