A hybrid approach for fast and accurate trace signal selection for post-silicon debug

The main challenge in post-silicon debug is the lack of observability to the internal signals of a chip. Trace buffer technology provides one venue to address this challenge by online tracing of a few selected state elements. Due to the limited bandwidth of the trace buffer, only a few state elements can be selected for tracing. Recent research has focused on automated trace signal selection problem in order to maximize restoration of the untraced state elements using the few traced signals. Existing techniques can be categorized into high quality but slow “simulation-based”, and lower quality but much faster “metric-based” techniques. This work presents a new trace signal selection technique which has comparable or better quality than simulation-based while it has a fast runtime, comparable to the metric-based techniques.