<p>Modern microprocessors utilize several techniques for extracting instruction-level parallelism (ILP) to improve the performance. Current techniques employed in the microprocessor include register renaming to eliminate register anti- and output (false) dependences, branch prediction to overcome control dependences, and data disambiguation to resolve memory dependences. Techniques for value prediction and value speculation have been proposed to break register flow (true) dependences among operations, so that dependent operations can be speculatively executed without waiting for producer operations to finish. This thesis presents a new combined hardware and compiler synergy, value speculation scheduling (VSS), to exploit the predictability of operations to improve the performance of microprocessors. The VSS scheme can be applied to dynamically-scheduled machines and statically-scheduled machines. To improve the techniques for value speculation, a value speculation model is proposed as solving an optimal edge selection problem in a data dependence graph. Based on three properties observed from the optimal edge selection problem, an efficient algorithm is designed and serves as a new compilation phase of benefit analysis to know which dependences should be broken to obtain maximal benefits from value speculation. A pure software technique is also proposed, so that existing microprocessors can employ software-only value speculation scheduling (SVSS) without adding new value prediction hardware and modifying processor pipelines. Hardware-based value profiling is investigated to collect highly predictable operations at run-time for reducing the overhead of program profiling and eliminating the need of profile training inputs.<P>
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-20010508-151111 |
| Date | 10 May 2001 |
| Creators | Fu, Chao-ying |
| Contributors | Thomas M. Conte, Paul D. Franzon, Wentai Liu, Eric Rotenberg |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-20010508-151111 |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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