Abstract: The equivalence on power-performance tradeoff of timeout and stochastic polices for dynamic power management is studied. The power-managed systems controlled by timeout or stochastic policies are formulated as semi-Markov control processes. Under this analytical framework,by analyzing the steady-state behaviors of the power-managed systems,the equivalence on performance-power tradeoff of timeout and stochastic policies is revealed,and the equivalent relation between these two types of policies is derived. The analysis results are demonstrated by numerical simulation experiments.