Reflex is a suite of compiler and runtime support for applications to leverage low-power processors on mobile systems. Low-power processors encompassed in an extremely asymmetric architecture promise very high energy-efficiency to frequent, simple computational tasks, most notably sensing. However, programming such an architecture is difficult, especially to numerous third-party developers. Reflex relieves developers from dealing with the extremely asymmetric architecture. It not only manages deployment and execution of an application that is distributed over the main and the low-power processors, but also creates a software Distributed Shared Memory (DSM) across the distributed code. Essentially, Reflex maintains high energy-efficiency while greatly easing the application development.