Have you ever wondered how virtual machines get access to the physical processor cores in the server?  Ever wonder why one or two VMs run slow sporadically?  The topic today is Virtual Processor Scheduling.  There are no good books to read on this subject, trust me I’ve looked.  Maybe in 10 years as a look back at the history of virtual computing, but not today.  So let’s try to shed some light on the subject for today’s article in our VMware or Microsoft? – The Complete Series.

First things first.  It is fairly simple to schedule against physical processors when the virtual machines each have a single virtual processor and there are plenty of physical cores to go around.  We (VMware and Microsoft) can send the workload to the first physical core that is available, easy.  There are algorithms for figuring out the best processor core to send the workload too, but I will not go into advanced crazy algorithm mathematics today.



Today’s VMware or Microsoft post comes from Tommy Patterson. You can view the full post on his blog -


Virtual Processor Scheduling – How VMware and Microsoft hypervisors work at the CPU level