
515Virtualizing Resources for the Cloud
Similar to a process on a general-purpose OS, a vCPU can be in different states
such as running, ready, and wait states. At a certain point in time, a vCPU can be
scheduled by the hypervisor at only a single core (akin to scheduling an OS process
at a core). For instance, a UP VM running on a host machine equipped with 2 × Xeon
5405 (i.e., total of 8 pCPUs) will run on only 1 of the 8 available cores at a time.
Inherently parallel workloads, such as MapReduce applications, prefer SMP VMs.
We next discuss how the hypervisor schedules vCPUs on pCPUs.
16.6.5 virtual CPu sCheDuling anD Xen’s sCheDulers
Genera ...