Big or Little: A Study of Mobile Interactive Applications on an Asymmetric Multi-core Platform

This paper characterizes a commercial mobile platform on an asymmetric multi-core processor, investigating its available thread-level parallelism (TLP) and the impact of core asymmetry on applications. This paper explores three critical aspects of asymmetric mobile systems, asymmetric hardware platform, application behavior, and the impact of scheduling and power management. First, this paper presents the performance and energy characteristics of a commercial asymmetric multi-core architecture with two core types. The comparison between big and little cores shows the potential benefit of asymmetric multi-cores for improving energy efficiency. Second, the paper investigates the available thread-level parallelism and core utilization behaviors of mobile interactive applications. Using popular mobile applications for the Android system, this paper analyzes the distinct TLP and CPU usage patterns of interactive applications. Third, the paper explores the impact of power governor and CPU scheduler on the asymmetric system. Multiple cores with heterogeneous core types complicate scheduling and frequency scaling schemes, since the scheduler must migrate threads to different core types, in addition to traditional load balancing. This study shows that the current mobile applications are not fully utilizing the asymmetric multi-cores due to the lack of TLP and low computational requirement for big cores.