Exploiting inter and intra application dynamism to save energy

The dynamism inside applications can be exploited to save energy. A proactive scheduler that exploits this dynamism through Dynamic Frequency and Voltage Scaling (DVFS) has been presented in [1][2]. So far, the claimed energy savings of this scheduler have never been demonstrated on a real hardware platform. In this paper, we show for the first time that the proactive scheduler from [1][2] is able to realize the claimed energy savings. Our experimental results show that this scheduler reduces the energy consumption of a MP3 decoder running on a TI Omap3530 board by 18%. The proactive scheduler from [1][2] can only be used on a system that is running a single application. In this paper, we extend this scheduler such that it can deal with multiple applications that are running concurrently. Our scheduler exploits both inter and intra application dynamism to save energy while providing timing guarantees to all applications. Experimental results show that our scheduler is able to achieve the same energy savings, 38%, as an optimized version of the Linux on demand scheduler when running two H.263 decoders concurrently. However, our scheduler achieves this result without any deadline misses, the on demand scheduler fails 10% of its deadlines leading to a substantial quality loss.