Applications in embedded systems often need to meet specified timing constraints. It is advantageous to not only calculate the Worst-Case Execution Time (WCET) of an application, but to also perform transformations that attempt to reduce the WCET, since an application with a lower WCET will be less likely to violate its timing constraints. A compiler has been integrated with a timing analyzer to obtain the WCET of a program on demand during compilation. This environment is used to investigate three different types of compiler optimization techniques to reduce WCET. First, an interactive compilation system has been developed that allows a user to interact with a compiler and get feedback regarding the WCET. In addition, a genetic algorithm is used to automatically search for an effective optimization phase sequence to reduce the WCET. Second, a WCET code positioning optimization has been investigated that uses worst-case path information to reorder basic blocks so that the branch penalties can be reduced in the worst-case path. Third, WCET path optimizations, similar to frequent path optimizations, are used to reduce the WCET. There are several contributions to this work. To the best of our knowledge, this is the first compiler that interacts with a timing analyzer to use WCET predictions during the compilation of applications. The dissertation demonstrates that a genetic algorithm search can find an optimization sequence that simultaneously improves both WCET and code size. New compiler optimizations have been developed that use WC path information from a timing analyzer. The results show that the WCET code positioning algorithms typically find the optimal layout of the basic blocks with the minimal WCET. It is also shown that frequent path optimizations can be applied on WC paths using worst-case path information from a timing analyzer to reduce WCET. These new compiler optimizations described in this dissertation not only significantly reduce WCET, but also are completely automatic. / A Dissertation submitted to the Department of Computer Science in partial
fulfillment of the requirements for the degree of Doctor of Philosophy. / Degree Awarded: Summer Semester, 2005. / Date of Defense: July 11, 2005. / WCET, Performance, Embedded / Includes bibliographical references. / David Whalley, Professor Directing Dissertation; Anuj Srivastava, Outside Committee Member; Theodore P. Baker, Committee Member; Robert A. van Engelen, Committee Member; Kyle Gallivan, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_168682 |
| Contributors | Zhao, Wankang (authoraut), Whalley, David (professor directing dissertation), Srivastava, Anuj (outside committee member), Baker, Theodore P. (committee member), Engelen, Robert A. van (committee member), Gallivan, Kyle (committee member), Department of Computer Science (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
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