Exploiting Hardware and Software Low power Techniques for Energy Efficient Co-Scheduling in Dynamically Reconfigurable Systems

Currently, the hardware and the software tasks in reconfigurable systems are either scheduled separately at run time or co-scheduled statically, which results in high power consumption and low performance. This work proposes runtime co-scheduling of hardware and software tasks by using the slack time, which is introduced due to reusing hardware task configurations, for dynamically scaling the processor voltage such that preceding software tasks consume lesser power. At the same time, the reuse of hardware task configurations also result in lower power consumption and higher performance due to fewer number of reconfigurations. The combined effects of hardware configuration reuse and software dynamic voltage scaling result in schedules with a lower power consumption and higher performance than that obtained through individual techniques applied to hardware and software separately. The proposed method was implemented in the SystemC-based Perfecto simulation environment for dynamically reconfigurable hardware software systems and TGFF was used for generating random task sets as input for Perfecto. We performed extensive experiments whose results show that irrespective of different slack ratios or hardware partitions, the schedules generated by our proposed method are more energy efficient than methods that either do not apply any runtime techniques or only apply hardware configuration prefetch and reuse.