A Virtual CPU Scheduling Mechanism Based on I/O-Awareness

A novel I/O-aware virtual CPU(vCPU)scheduling mechanism in virtualized environments based on multi-core platform is proposed to eliminate the semantic gap between guest and virtual machine monitor(VMM)that dramatically degrades the performance of I/Obound workloads in virtual symmetric multi-core processor(vSMP)virtual machine(VM).Inference techniques are used to identify the I/O-bound tasks,and the I/O-bound tasks and I/O events are correlated through the coordination between the guest operating system and VMM.Then the correlation information is used to bridge the semantic gap by a vSMP Internal algorithm so that a vCPU with I/O-bound task can selectively be scheduled to handle its incoming events promptly with ensured fairness among VMs.Extensive evaluations and comparisons with the CFS scheduler used by the KVM virtual machine monitor show that the proposed mechanism significantly improves I/O performance of vSMP VMs with ensured CPU fairness,and little overhead is introduced to guest.Therefore,the proposed mechanism is widely applicable in suchenvironments with unpredictable and varying workloads as virtual desktop and cloud computing.