Research Of Scheduling Techniques On Big.LITTLE For User Experience And Energy Efficiency Of Mobile Device

With the increasing number of mobile devices,users are increasingly demanding the performance of mobile devices.Smart phones are the most widely used mobile devices.The biggest difference between mobile devices and traditional PCs is their mobility.It is impossible to connect the power supply all the time,and the capacity of batteries is very limited.How to extend the lifetime of mobile devices under the premise of meeting the minimum usage requirements has become the focus of common concern of industry and users.Heterogeneous multi-core mobile platforms are widely used to improve performance.However,battery technology has not made significant progress,resulting in limited battery capacity limiting the energy consumption of mobile devices.Therefore,the performance and energy consumption of heterogeneous multi-core mobile platforms conflict.Researchers at home and abroad have put forward many solutions to solve the problem of balance between the two.Big.LITTLE architecture is an energy-saving heterogeneous computing architecture proposed by ARM.Many mobile devices with big.LITTLE architecture are efficient and energy-saving to a certain extent.In addition to performance and energy consumption,user experience is a particularly important concern in the design of modern mobile platforms,which is often neglected in the solution of balancing performance and energy consumption,so as to bring bad user experience to mobile users.Based on the original global task scheduling on big.LITTLE processor,this paper proposes an improved global task scheduling called user importance and low power global task scheduling(UCEE-GTS).In UCEE-GTS,the concept of user-centered tasks is introduced to enhance user experience.The response speed of the application is the simplest and most direct expression of the user experience.This paper quantifies the user experience with the response time of user-centered tasks.This paper makes some improvements based on the original global task scheduling,such as user-centered task partitioning and non-user-centered tasks.When a task is in the interactive state or in the foreground,it belongs to the user-centered task,otherwise it belongs to the non-user-centered task.In order to enhance the user experience,the response time of user-centered tasks is shortened by reducing the relaxation time appropriately.For interactive tasks,UCEE-GTS assigns them to large cores,because large cores have higher computing power,so interactive tasks can shorten response time.In addition,the deadline for backstage tasks should be appropriately extended to achieve maximum energy efficiency.Then,an algorithm is proposed to calculate the appropriate frequency and assign the computing period to each task.Our experimental results show that,compared with GTS and cluster switching scheduling model,UCEE-GTS achieves the trade-off between energy consumption and performance,and achieves excellent user experience.