DiAMOND:Distributed alteration of messages for on-chip network debug

During emulation and post-silicon validation of networks-on-chip (NoCs), lack of observability of internal operations hinders the detection and debugging of functional bugs. Verifying the correctness of the control-flow portion of the NoC requires tests that exercise its functionality, while abstracting the data content of traffic. We propose a methodology where network packets are repurposed for the storage of debug information collected during execution. Debug data pertaining to each packet is collected at routers along its path and stored by replacing the packet's original data content. Our solution is coupled with a detection scheme consisting of small checkers that monitor execution and flag bugs. Upon bug detection, we analyze the debug information to reconstruct network traffic.We also provide relevant statistics for debugging, such as packet interactions and packet latencies, per router. In our experiments, this approach allows us to reconstruct over 80% of the packets' routes. Moreover, the obtained statistics facilitate debugging erroneous network behavior and identifying performance bottlenecks.