Improving Energy Efficiency Via Speculative Multithreading on MultiCore Processors

  • Toshinori Sato
  • Yuu Tanaka
  • Hidenori Sato
  • Toshimasa Funaki
  • Takenori Koushiro
  • Akihiro Chiyonobu
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4148)


The advance in semiconductor technologies has increased the number of transistors on a die, resulting in the continuous improvement in microprocessor performance. However, the increase in power consumption and hence in power density is about to stop the progress in microprocessor performance. While supply voltage reduction is commonly known as an effective technique for power savings, it increases gate delay and thus causes performance degradation. The increasing transistors can be utilized for maintaining performance while reducing power consumption. We are considering a speculative multithreaded execution on MultiCore processors. We propose to execute only the part of the program, which has the impact on program execution time, on power-hungry cores. In order to enable this, we divide the instruction stream into two streams. One is called speculation stream, which is the main part of a program and where speculation is applied. It is executed on power-hungry cores. The other is the verification stream, which verifies every speculation. It is executed on low-power cores. The energy consumption is reduced by the decrease in the execution time in the speculation stream and by the low-power execution in the verification stream. We call this technique Contrail architecture. The paper will present the energy efficiency of a Contrail processor based on detailed simulations.


Clock Frequency Improve Energy Efficiency Leakage Power MultiCore Processor Processor Performance 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Toshinori Sato
    • 1
  • Yuu Tanaka
    • 2
  • Hidenori Sato
    • 3
  • Toshimasa Funaki
    • 4
  • Takenori Koushiro
    • 5
  • Akihiro Chiyonobu
    • 4
  1. 1.System LSI Research CenterKyushu UniversityFukuokaJapan
  2. 2.Kyushu Railway CompanyFukuokaJapan
  3. 3.Seiko Epson CorporationSuwaJapan
  4. 4.Graduate School of Computer Science and System EngineeringKyushu Institute of TechnologyIizukaJapan
  5. 5.Toshiba CorporationKawasakiJapan

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