Optimized Inter-domain Communication Based On Shared Memory

Virtualization technology provides diverse and specific execution environment to the upper application. Virtualization technology can provide flexible, efficient and safe management and utilization of different computing resources. As virtualization technology gets mature and the public demand for a variety of functions,virtualization technology has been applied in various fields. Virtualization technology not only provides great convenience to the public enterprises but reduces application costs.Virtualization technology has been applied to many areas, including server consolidation. Therefore, the communication between virtual machines will be very complex and frequent, and the performance of the communication between virtual machines becomes very important. However, due to the increase of the communication path, frequent kernel involvement and other reasons, the performance of the communication between virtual machines is affected by different aspects.Therefore, to optimize communication performance between different virtual machines on the same physical machine has great scientific value.On the basis of the related work about inter-domain communication, this paper studies the inter-domain communication optimization in the Xen virtual environment.The main work of this paper are summarized as follows:(1) Firstly, this paper demonstrates the process of the inter-domain communication on the same physical machine under Xen and analysis the communication performance overhead in detail. To complete the inter-domain communication on the same physical machine under Xen, the transferring data need to be copied to the kernel, then encapsulated by the TCP/IP protocol and transferred to the other domain through a complex flow control protocol, in addition, multiple check operations like checksum and handshake mechanism need to be done in the process of transmission to ensure the transmission of information correctly, which will result in multiple context switches. The process of the inter-domain communication not only extends the communication path, but largely degrades the communication performance.(2) This paper presents a model for optimizing the communication betweenvirtual machines on the Xen system. This model is based on shared memory and the key idea consists in mapping pages of shared memory directly into userspaces, and thus getting rid of useless system calls. It can achieve high performance by bypassing TCP/IP protocol stack and privileged domain, and providing a direct and high-performance communication path between two virtual machines. The optimized model substantially increases the communication bandwidth and throughput, reduces the communication round-trip delay, effectively improves the communication performance between virtual machines.(3) To prove the good communication performance of the proposed optimized model, we designed and conducted a series of evaluations. Evaluations are aimed to compare the communication performance of the optimized model with the traditional TCP/IP mode. The evaluations verified this optimized model has better communication performance than the traditional TCP/IP mode through testing throughout, communication delay, CPU utilization and number of Hypercall.Evaluations results show that the optimized model can effectively enhance the communication performance between different virtual machines on the same physical machine.