Dissertation/Thesis Abstract

Post-silicon Functional Validation with Virtual Prototypes
by Cong, Kai, Ph.D., Portland State University, 2015, 143; 3712209
Abstract (Summary)

Post-silicon validation has become a critical stage in the system-on-chip (SoC) development cycle, driven by increasing design complexity, higher level of integration and decreasing time-to-market. According to recent reports, post-silicon validation effort comprises more than 50% of the overall development effort of an 65nm SoC. Though post-silicon validation covers many aspects ranging from electronic properties of hardware to performance and power consumption of whole systems, a central task remains validating functional correctness of both hardware and its integration with software. There are several key challenges to achieving accelerated and low-cost post-silicon functional validation. First, there is only limited silicon observability and controllability; second, there is no good test coverage estimation over a silicon device; third, it is difficult to generate good post-silicon tests before a silicon device is available; fourth, there is no effective software robustness testing approaches to ensure the quality of hardware/software integration.

We propose a systematic approach to accelerating post-silicon functional validation with virtual prototypes. Post-silicon test coverage is estimated in the pre-silicon stage by evaluating the test cases on the virtual prototypes. Such analysis is first conducted on the initial test suite assembled by the user and subsequently on the expanded test suite which includes test cases that are automatically generated. Based on the coverage statistics of the initial test suite on the virtual prototypes, test cases are automatically generated to improve the test coverage. In the post-silicon stage, our approach supports coverage evaluation of test cases on silicon devices to ensure fidelity of early coverage evaluation. The generated test cases are issued to silicon devices to detect inconsistencies between virtual prototypes and silicon devices using conformance checking. We further extend the test case generation framework to generate and inject fault scenario with virtual prototypes for driver robustness testing. Besides virtual prototype-based fault injection, an automatic driver fault injection approach is developed to support runtime fault generation and injection for driver robustness testing. Since virtual prototype enables early driver development, our automatic driver fault injection approach can be applied to driver testing in both pre-silicon and post-silicon stages.

For preliminary evaluation, we have applied our coverage evaluation and test generation to several network adapters and their virtual prototypes. We have conducted coverage analysis for a suite of common tests on both the virtual prototypes and silicon devices. The results show that our approach can estimate the test coverage with high fidelity. Based on the coverage estimation, we have employed our automatic test generation approach to generate additional tests. When the generated test cases were issued to both virtual prototypes and silicon devices, we observed significant coverage improvement. And we detected 20 inconsistencies between virtual prototypes and silicon devices, each of which reveals a virtual prototype or silicon device defect. After we applied virtual prototype-based fault injection approach to virtual prototypes for three widely-used network adapters, we generated and injected thousands of fault scenarios and found 2 driver bugs. For automatic driver fault injection, we have applied our approach to 12 widely used drivers with either virtual prototypes or silicon devices. After testing all these drivers, we found 28 distinct bugs.

Indexing (document details)
Advisor: Xie, Fei
Commitee: Li, Fu, Li, Jingke, Singh, Suresh
School: Portland State University
Department: Computer Science
School Location: United States -- Oregon
Source: DAI-B 76/11(E), Dissertation Abstracts International
Subjects: Electrical engineering, Computer science
Keywords: Concolic test generation, Coverage evaluation, Driver robustness testing, Fault injection, Post-silicon functional validation, Virtual prototypes
Publication Number: 3712209
ISBN: 978-1-321-88881-2
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