Extended fractional symmetric multi-processing capabilities to guest operating systems

Operating at least one hypervisor includes running a first hypervisor as a first thread of an underlying operating system, running a second hypervisor as a second thread of the underlying operating system, loading a first guest operating system using the first hypervisor based on the first thread of the underlying operating system, loading a second guest operating system using the second hypervisor based on the second thread of the underlying operating system, and scheduling sharing of resources of the underlying system between the first hypervisor and the second hypervisor according to a scheduler of the underlying operating system, where the first hypervisor and the second hypervisor run independently of each other. The scheduler of the underlying operating system may schedule fractional time shares for the first hypervisor and the second hypervisor to access the same resource.