Optimizing Bandwidth of Call Traces for Wireless Embedded Systems

Call traces expose runtime behaviors that greatly aid system developers in profiling performance and diagnosing problems within wireless embedded applications. Strict resource constraints limit the volume of trace data that can be handled on embedded devices, especially bandwidth limited wireless embedded systems. We propose two new call trace gathering techniques, local identifier logging and control flow logging, which provide significant reductions in bandwidth consumption compared to the current standard practice of global identifier logging. Intuition into the savings made possible by the proposed trace gathering techniques is provided by an analytical comparison of the bandwidth required by various call tracing approaches. Confirmation of this intuition is demonstrated through experimentation that reveals log bandwidth savings of approximately 85% compared to global identifier logging using flat name spaces, and 35% compared to global identifier logging using optimal Huffman coding.