DVFS

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DVFS, Wikipedia An article that need to be written.

Video Decoding

Switching Overhead

-Xeon C-state transition times
-P-state frequency example, (10 133MHz steps from 1.2GHz to 2.53Ghz)
-"On dual-core Athlon X2 and Phenom I, it was for example impossible to use DVFS and get decent HD-video decoding. There are three important performance problems with dynamic power management:
Transitioning from one P-state to another takes a while, especially if you scale up. Active cores will probe idle or lower P-state cores quite frequently. The OS power manager has to predict whether or not the process will need more processing power soon or not. As a result the OS transitions a lot slower than the hardware."
-p. 168: "Processor core (including shared cache) is unavailable for less than 2us during the frequency transition."
Power consumption table for 5600 by C-state
-p. 167: "Processor C-State Power Specifications" table power consumption by C-state
Power consumption table for several processors at different power management C-states
-20us transition overhead for all C-states?
-Overview charts on C-State configuration details wakeup times and power consumption
-Gives wakeup times, but don't know where they came from
-example power performance by P-states

DVFS Project Resources

Concise references for DVFS project from 2003 using speedstep on an IBM Thinkpad
Good linux kernel reference
  • Topic: Addressing the power cost of switching overhead in DVFS processors.

Experimental Setup

DVFS Papers

  • Burd, T.; Pering, T.; Stratakos, A.; Brodersen, R.; , A dynamic voltage scaled microprocessor system. Solid-State Circuits Conference, 2000. Digest of Technical Papers. ISSCC. 2000 IEEE International , vol., no., pp.294-295, 466, 2000.
Prediction and switching overhead

Exploiting Hardware-Assisted Asynchronous Dynamic Voltage Scaling, North Carolina State University"]

DVFS in Linux