Dynamic performance tuning for speculative threads

Yangchun Luo, Venkatesan Packirisamy, Wei Chung Hsu, Antonia Zhai, Nikhil Mungre, Ankit Tarkas

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

26 Scopus citations


In Response to the emergence of multicore processors, various novel and sophisticated execution models have been introduced to fully utilize these processors. One such execution model is Thread-Level Speculation (TLS), which allows potentially dependent threads to execute speculatively in parallel. While TLS offers significant performance potential for applications that are otherwise non-parallel, extracting efficient speculative threads in the presence of complex control flow and ambiguous data dependences is a real challenge. This task is further complicated by the fact that the performance of speculative threads is often architecture-dependent, input-sensitive, and exhibits phase behaviors. Thus we propose dynamic performance tuning mechanisms that determine where and how to create speculative threads at runtime. This paper describes the design, implementation, and evaluation of hardware and software support that takes advantage of runtime performance profiles to extract efficient speculative threads. In our proposed framework, speculative threads are monitored by hardware-based performance counters and their performance impact is estimated. The creation of speculative threads is adjusted based on the estimation. This paper proposes speculative threads performance estimation techniques, that are capable of correctly determining whether speculation can improve performance for loops that corresponds to 83.8% of total loop execution time across all benchmarks. This paper also examines several dynamic performance tuning policies and finds that the best tuning policy achieves an overall speedup of 36.8% on a set of benchmarks from SPEC2000 suite, which outperforms static thread management by 9.5%.

Original languageEnglish (US)
Title of host publicationISCA 2009 - 36th Annual International Symposium on Computer Architecture, Conference Proceedings
Number of pages12
StatePublished - 2009
EventISCA 2009 - 36th Annual International Symposium on Computer Architecture - Austin, TX, United States
Duration: Jun 20 2009Jun 24 2009

Publication series

NameProceedings - International Symposium on Computer Architecture
ISSN (Print)1063-6897


OtherISCA 2009 - 36th Annual International Symposium on Computer Architecture
Country/TerritoryUnited States
CityAustin, TX


  • Dynamic optimization
  • Multicore
  • Thread-level speculation


Dive into the research topics of 'Dynamic performance tuning for speculative threads'. Together they form a unique fingerprint.

Cite this