I have an Ubuntu host with an AMD Matisse processor (12C 24T). When launching virtual machines using libvirt (QEMU+KVM), there's the option to set CPU topology.
Almost all consumer PCs have single-socket CPU with multiple cores and up to 2 threads per core (HT), so I'm tempted to set a similar topology for the VM. I wonder if this setting alone (assume total CPU threads remains constant) affects VM performance or host CPU utilization, for example with regards to scheduling.