| Summary: | 碩士 === 中原大學 === 資訊工程研究所 === 100 === As the growing functionality of modern hand-held devices, the requirement of system performance is increased. The multicore processors are widely adopted in the hand-held systems accordingly. Since the hand-held systems are powered by battery, the battery life will become the dominated limitation of these high-performance multicore hand-held devices. Therefore an efficient power management mechanism for hand-held multicore system is become important today. Conventional power management systems of embedded systems, such as Linux power CPU power manager, Android peripheral manager, adopt an automatic scheme to control the usage of peripheral operations and processor frequency. It can not consider the requirement of user, actually task loading, and power-on/shutdown processors in the multicore system, to meet the actual operating situation. Therefore, this paper propose a novel power management mechanism, called Bounded-Power Multi-core Dynamic Frequency Scaling (BPM-DFS), which integrates a system configuration selection algorithm, a task re-scheduling mechanism, and a predictive power model. According to the assigned power budget by the user, BPM-DFS can dynamically adjust the configuration of the multicore system to control the suitable alive core number, working frequency, and task reassignment, to achieve good performance and under the limitation of power consumption. The proposed BPM-DFS has been implemented on quad-core x86 Android system to compare the actual capabilities of other power management schemes, such as SCA-ICA, Linux/Android build-in power managers. The experimental results reveal that BPM-DFS can save 25 % power consumption than Linux performance mode; save 21% power consumption than SCA-ICA. It also can save 2% power consumption than the most low-power Linux operation mode, Linux powersave mode.
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