UBC Theses and Dissertations

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UBC Theses and Dissertations

Post-silicon code coverage for functional verification of systems-on-chip Karimibiuki, Mehdi


Post-silicon validation requires effective techniques to better evaluate the functional correctness of modern systems-on-chip. Coverage is the standard measure for validation effectiveness and is extensively used pre-silicon. However, there is little data evaluating the coverage of post-silicon validation efforts on industrial-scale designs. This thesis addresses this knowledge-gap. We employ code coverage, which is one of the most frequently used coverage technique in simulation, and apply it post-silicon. To show our coverage methodology in practice, we employ an industrial-size open source SoC that is based on the SPARC architecture and is synthesizable to FPGA. We instrument code coverage in a number of IP cores and boot Linux as our experiment to evaluate coverage --- booting an OS is a typical industrial post-silicon test. We also compare coverages between pre-silicon directed tests and the post-silicon Linux boot. Our results show that in some blocks, the pre-silicon and post-silicon tests can achieve markedly different coverage figures --- in one block we measured over 50 percentage point coverage difference between the pre- and post-silicon results, which signifies the importance of post-silicon coverage. Moreover, we calculate the area overhead imposed by the additional coverage circuitry on-chip. We apply state-of-the-art software analysis techniques to reduce the excessively large overhead yet preserve data accuracy. The results in this thesis are valuable data for guidance to future research in post-silicon coverage.

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