Computing while charging: Building a Distributed Computing Infrastructure Using Smartphones. CoNEXT

Every night, a large number of idle smartphones are plugged into a power source for recharging the battery. Given the increasing computing capabilities of smartphones, these idle phones consti-tute a sizeable computing infrastructure. Therefore, for an enter-prise which supplies its employees with smartphones, we argue that a computing infrastructure that leverages idle smartphones be-ing charged overnight is an energy-efficient and cost-effective alter-native to running tasks on traditional server infrastructure. While parallel execution and scheduling models exist for servers (e.g., MapReduce), smartphones present a unique set of technical chal-lenges due to the heterogeneity in CPU clock speed, variability in network bandwidth, and lower availability compared to servers. In this paper, we address many of these challenges to develop CWC—a distributed computing infrastructure using smartphones. Specifically, our contributions are: (i) we profile the charging be-haviors of real phone owners to show the viability of our approach, (ii) we enable programmers to execute parallelizable tasks on smart-phones with little effort, (iii) we develop a simple task migration model to resume interrupted task executions, and (iv) we imple-ment and evaluate a prototype of CWC (with 18 Android smart-phones) that employs an underlying novel scheduling algorithm to minimize the makespan of a set of tasks. Our extensive eval-uations demonstrate that the performance of our approach makes our vision viable. Further, we explicitly evaluate the performance of CWC’s scheduling component to demonstrate its efficacy com-pared to other possible approaches