FlashDAM: Flexible I/O Throttling for the User Experience of Mobile Systems

I/O plays an important role in the user experience. However, their quick response cannot be ensured in mobile systems, which is always blamed by users. Our study indicates that poor response is always caused by Flash-device side congestion, instead of I/O scheduling in the system layer. Unfortunately, the Flash device is treated as a black box and is not allowed to be modified after delivery. This paper explores a new approach to address the in-device problem without any invasive modification in the Flash. In this paper, we propose FlashDAM, a flexible I/O throttling framework in mobile systems. Contrary to the common belief, FlashDAM shows that proper I/O throttling, rather than straightforward boosting, has a positive effect on the user experience. We have implemented FlashDAM on off-the-shelf smartphones. Experimental results show that the application launch speed and frame rate stability can be enhanced by 72% and 45% separately, compared to the state-of-the-art.