Overview and benchmarks of pragmatic debugging techniques for wireless sensor networks

Debugging of sensor nodes is tiresome and time-consuming, mainly because of limited debug features of nodes and complex interactions in sensor networks. Besides, each software level (hardware drivers, communication protocols, applications) needs a different approach to trace bugs. This paper surveys practical techniques that support bug tracing on nodes at various levels. Bugs may disappear when the program is being tested, for debugging results in extra processing delays. In this paper, we attack this problem by performing a set of micro-benchmarks for common debug techniques. We show their impact on the execution time and also their memory footprint. Based on our experience, we claim assertions to be the most effective debug technique for sensor networks. They result in negligible delays, less than a microsecond, making them suitable for any software level: from hardware drivers to applications. Further, since assertions stop the program execution just after detecting a failure, they narrow down the root cause of the problem. Finally, assertions support bug tracing in PC simulations and on real sensor nodes.