The Research On Multi-level I/O Virtualization Technology Based On Cooperative Model

At present, the researches on technology of system virtualization are mainly focused on thefunction and performance improvement of the processor and memory, so that the virtualizationof processor and memory can better meet the various needs. In contrast, the methods andperformance of I/O virtualization is laggard, which restricts the wide range of applications ofvirtualization deployment in the I/O intensive environments. So, it is important to study thetechnology of I/O virtualization.The current I/O virtualization technologies including emulation or simulation on thesoftware layer, directly assigned devices by the bus layer’s support and multi-interfaces by thedevice layer’s support. The characteristics of different I/O virtualization technologies can beused to meet specific needs of users, but there are some ubiquitous problems such as thecontradiction between performance and compatibility on the software layer, the gap ofdeviceshared on bus layer which support directly assigning devices and the restriction inapplication on device layer which requires hardware support. The current I/O virtualizationtechnologies are very difficult to provide multi-level support with high I/O throughput and cannot meet the actual needs of users such as device compatibility and sharing.To the aboved insufficiency of I/O virtualization technologies, the thesis proposes amulti-level I/O virtualization framework named ME-IOVF which based on the cooperationmodel. ME-IOVF integrates different levels’ technologies of I/O virtualization to solve theproblems that brought by tight coupling between operating environment and VMM or VM, andthe problems brought by single virtual mode. The thesis mainly solved the following threeproblems:1. ME-IOVF provides a loosely coupled operating environment of devices model to ensurethe timely I/O processing.2. ME-IOVF integrates multi-levels I/O virtualization technologies including the simulationon software layer, the VT-d and SR-IOV method, which better improves I/O performance andmeets different user needs.3. The thesis presents an optimization strategy with dynamic adjustment for devices directlyassigned. The strategy dynamicly adjusts devices according to the priority, which avoids theclients’ waiting and improves the performance of the vitualization system.Experiments showed that the performance of software simulation and direct deviceassignment in ME-IOVF has a certain improvement compared with Xen/KVM/QEMU. Theperformance of I/O which used the NIC dynamic assigned had significant amelioration. Thus,ME-IOVF designed in this thesis has a certain advantage in performance and versatility.