| With the rapid development of virtualization technology, it has been widely applied in the areas of server consolidation, cluster computing, multiple OS configurations, hardware and kernel development, etc. The CPU scheduler is an important approach to allocate the processors in virtualization technology. The performance of scheduler plays a key role in the rate of disk reading/writing, network throughput, CPU allocation accuracy and so on. Therefore, the research on the scheduler will have both important theoretical and important applicational value.Based on the thoroughly research of kernel of Xen, this paper analyzes the implementation principle of the existing three schedulers, which are BVT, SEDF and Credit. Combining with the SEDF and Credit schedulers, the paper proposes a scheduler with the name of IEDF that can implement the global dynamic load balancing on SMP. The scheduler can dynamically allocate the VCPUs to the light-loaded processors by Real-Time monitoring the current load of per processor; When a VCPU finishes its running, the scheduler can dynamically adjust VCPU parameters based on its' running status; In the process of VCPU scheduling, the VCPUs those can be finished before its absolute deadline will take precedence over other VCPUs; Before a processor goes idle, it will consider other processors in order to migrate a ready VCPU to the processor.Based on the design of Schedsim scheduling simulator, the paper designs and realizes IEDF scheduler and SEDF scheduler on SMP. Roundly performance tests and comparison have been done for the two schedulers. The results manifest that the IEDF scheduler can greatly improve the performance. |
