Q: Does Azure oversubscribe physical cores to virtual machine cores?
A: No; there's no oversubscribe of cores in Azure. Resources for virtual cores are guaranteed to be available. Note that with Generation 3 Azure servers, timeslicing may be used where consistent performance with Generation 2 Azure servers is required. Prior to Generation 3 servers each logical core mapped 1:1 to a virtual machine core, except for the A0 virtual machine size, which uses a shared core.