Flip-flop clustering based trace signal selection for post-silicon debug
Yun Cheng, Huawei Li, Ying Wang, Yingke Gao, Bo Liu, Xiaowei Li · 2017
The lack of observability of prototype chips makes post silicon debug extremely difficult and time consuming. Trace based debug techniques can improve the observability by acquiring some internal states at runtime through a dedicated on-chip trace buffer. In this paper, we propose a flip-flop clustering based trace signal selection method, which uses the forward tracing to generate flip-flop clusters and evaluates the global state restoration improvement to select the clusters for state capturing. The predecessor flip-flops of the selected cluster are used as trace signals, and the internal flip-flops of the selected clusters are used as snapshot signals. The experimental results show that in comparison with the prior methods, our method can increase the state restoration ratio by 74.8% on average with no more than 1.58% storage overhead for storing snapshots. The runtime for trace signal selection is also much less than those of prior methods.