Constrained signal selection for post-silicon validation

Limited signal observability is a major concern during post-silicon validation. On-chip trace buffers store a small number of signal states every cycle. Existing signal selection techniques are designed to select a set of signals based on the trace buffer width. In a real-life scenario, it is reasonable that a designer has determined some important signals that must be traced. In this paper, we study the constrained signal selection problem where a set of trace signals are already provided by the designer and the remaining signals have to be determined to improve overall restoration performance. Our experimental results using ISCAS´89 benchmarks demonstrate that up to 5% improvement can be obtained in restoration performance compared to existing approaches.