Analysis and Enhancement for Interactive-Oriented Virtual Machine Scheduling

Recently, there has been increasingly interest in hosting desktop applications in virtual machine environment and accessing them with thin-client devices. However, the interactive performance in such scenario has not been fully investigated yet. We thus measure the performance of the interactive desktop system hosted by Xen VMM. Our experimental results show that with heave workload VMs coexisting on the same physical server, one guest domain may get poor interactive performance for the existence of occasional large "latency-peak". We argue that for interactive operation, the larger variance of response latency, instead of the longer latency itself, is the most important performance problem for the virtualized approach. We enhance the credit scheduler of Xen to minimize both the height and frequency of latency peak. The results exhibited improvements in average height of latency-peak of up to 97.4% and in frequency of latencypeak of up to 94.2% for a variety of consolidation scenarios.