Speed Scaling

Keywords and Synonyms

Speed scaling;  Voltage scaling;  Frequency scaling  

Problem Definition

Speed scaling is a power management technique in modern processor that allows the processor to run at different speeds. There is a power function P(s) that specifies the power, which is energy used per unit of time, as a function of the speed. In CMOS-based processors, the cube-root rule states that ${ P(s) \approx s^3 }$. This is usually generalized to assume that ${ P(s)=s^\alpha }$ form some constant α. The goals of power management are to reduce temperature and/or to save energy. Energy is power integrated over time. Theoretical investigations to date have assumed that there is a fixed ambient temperature and that the processor cools according to Newton's law, that is, the rate of cooling is proportional to the temperature difference between the processor and the environment.

In the resulting scheduling problems, the scheduler must not only have a job‐selection policy to determine the...