Research And Implementation Of The Optimization Of Xen Inter Domain Communication

Virtualization technology was first appeared in mainframe computer, introduced by IBM in 1960s. It is a virtual layer introduced above existed layers which intercept and capture calls to under layer interface, re-explain and process it to realize new, different functions that existed software or hardware provided. As there is a growing trends to use virtual machine for server consolidation and system security enhancement in distributed computing environment, virtualization technology has attracted much interest in recently days. Virtualization technology is expanding its popularity in the field of PC and workstations.Virtualization technology can provide an isolated execution environment to applications, shield the dynamics and heterogeneous of hardware platform, and support share and reuse of hardware resources. It also can realize server consolidation, saving money and realize resource utilization; moreover, fault isolation can be achieved to enhance system security.Server consolidation is one of the most important applications of virtualization. It can realize hardware reuse, reduce power consumption and cut the cost of enterprise to run. Usually, server consolidation deploys multiple layers of services on one server. Those layers cooperate closely to provide various services for different users. As those different layer deployed in different virtual machines, the communication between those virtual machines will be very frequent. But current inter-domain communication mechanism on Xen will leads to low performance, thus depress the performance of server consolidation and can not achieve the biggest benefit.This thesis investigates the mechanism and finds the bottleneck of Xen inter-domain communication, based on those findings, we developed IDCO inter-domain communication optimization model to improve it's performance.Currently, when one guest domain in Xen wants to communicate with another which on the same physical machine, it will first sends the request to its front-end, then front-end will send it to back-end in domain0, this will leads to a domain switch, then backend will send request to driver model in domain0's user level for further process. Not only will this process extends the data transfer path, but also will produce enormous domain switches and TLB misses, severely degrades the performance of inter-domain communication.To solve this problem and improve the performance of inter-domain communication on the same physical machine, based on the observation of related works and combined with our own research, this thesis design and implement a new model for inter-domain communication: IDCO model. IDCO model uses hypercalls to set up connection, achieves high throughput via grant table based shared-memory, not only greatly improved communication bandwidth and reduced latency, but also eliminate the unnecessary domain switch. IDCO model greatly improved the performance of inter-domain communication on the same physical machine.Finally, to evaluate the correctness and performance of IDCO model, the thesis setup experiment environment and design evaluation solutions, presents the performance of IDCO in the following metrics: bandwidth, CPU, latency, and domain switch numbers. Experiment results show that IDCO model dramatically improved the performance of inter-domain communication on the same physical machine.