Cloud is not a silver bullet: A case study of cloud-based mobile browsing

In recent years, there has been growing interest in both in-dustry and academia in augmenting mobile web browsing with support from the cloud [4, 1, 3, 16, 18]). These ef-forts are motivated by the goals of lowering costs of data transfer, and reducing web latencies and device energy con-sumption. While these efforts have adopted different ap-proaches to cloud-based browsing, there is little systematic understanding of the rich design space given the proprietary nature of many of the solutions. In this paper, we take a first step towards obtaining such deeper understanding by evaluating an extreme point in the design space that involves cloud support for most browsing functionality in-cluding execution of JavaScript (JS), and for compaction of data (e.g., image transcoding and compression). Our study is conducted in the context of Cloud Browser (CB), one of the most popular commercially available browsers that em-bodies this design point. Our results indicate that CB does not provide clear benefits over Direct either in energy or download time. For e.g. while CB decreases the download time compared to Direct for 38.87 % of pages, it increases the download time by as much as 29.8s for other pages. Sim-ilarly while CB decreases the total energy by up to 20.77J compared to Direct for 52.7 % of the pages, it increases the total energy by up to 21.31J for other pages. Interestingly, even though CB does JS execution in the cloud, it increases the CPU and network energy for close to 50 % of the pages. Overall these results indicate that cloud-based browsing is not always a win, and there are important trade-offs that must be carefully considered when moving functionality to the cloud.