Synthesizing a representative critical path for post-silicon delay prediction

Qunzeng Liu, Sachin S Sapatnekar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

31 Scopus citations

Abstract

Several approaches to post-silicon adaptation require feedback from a replica of the nominal critical path, whose variations are intended to reflect those of the entire circuit after manufacturing. For realistic circuits, where the number of critical paths can be large, the notion of using a single critical path is too simplistic. This paper overcomes this problem by introducing the idea of synthesizing a representative critical path (RCP), which captures these complexities of the variations. We first prove that the requirement on the RCP is that it should be highly correlated with the circuit delay. Next, we present two novel algorithms to automatically build the RCP. Our experimental results demonstrate that over a number of samples of manufactured circuits, the delay of the RCP captures the worst case delay of the manufactured circuit. The average prediction error of all circuits is shown to be below 2.8% for both approaches. For both our approach and the critical path replica method, it is essential to guard-band the prediction to ensure pessimism: our approach requires a guard band 30% smaller than for the critical path replica method.

Original languageEnglish (US)
Title of host publicationProceedings of the 2009 International Symposium on Physical Design, ISPD'09
Pages183-190
Number of pages8
DOIs
StatePublished - Sep 21 2009
Event2009 International Symposium on Physical Design, ISPD'09 - San Diego, CA, United States
Duration: Mar 29 2009Apr 1 2009

Publication series

NameProceedings of the International Symposium on Physical Design

Conference

Conference2009 International Symposium on Physical Design, ISPD'09
CountryUnited States
CitySan Diego, CA
Period3/29/094/1/09

Keywords

  • Post-silicon optimization
  • Representative critical path

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