Qsync: Co-scheduling constrained virtual machines in the Xen hypervisor

Computer hardware advancements are generating excess computation resources resulting in increased system under-utilization. Infrastructure-as-a-Service (IaaS) corporations are capitalizing on this phenomenon by providing virtualization solutions expeditiously, effectively, and reliably to companies across a spectrum of industries. As these datacenters become ubiquitous, software applications are increasing being hosted on virtualized systems.;As utilization of these virtualized systems increases, hypervisors are necessarily reducing the available resources which introduces latency and variability to the applications. Communication-intensive applications in particular suffer substantial performance degradation and non-deterministic behavior operating under these conditions. Latency-sensitive applications demand strict a requirement for response time and variability which are not being met.;This thesis discusses qsync, a light-weight synchronization algorithm for a cluster of guest virtual machines on the Xen 4.5 hypervisor without requiring synchronization of the host system. The data shows the qsync synchronization algorithm reduces latency and variability, increasing the reliability of the environment even under strict CPU utilization limits.