Stethoscope: A Sustainable Runtime Debugger for Wireless Sensor Networks

Debugging wireless sensor networks (WSNs) is notoriously difficult, due to the resource constraints on the sensors and distributed running of the debugged programs. Many bugs only manifest themselves during the actual operation of a network, thus requiring runtime debugging of the sensor program. A WSN debugger has to meet two important design criteria, namely saving energy and preserving responsiveness to normal system/network events during debugging. In this paper, we propose Stethoscope, a sustainable runtime debugger for WSNs. In Stethoscope, we devise a new technique called Quick Switch, which enables dynamic binary instrumentation in the RAM instead of the program flash. By incorporating a light-weight hooking mechanism, Stethoscope ensures runtime responsiveness of the debugged program. We implement Stethoscope and demonstrate its advantages with respect to efficacy, energy consumption, and memory cost.