Low-Power Buffer Management for Streaming Data

In this paper, a method for reducing the power consumption in a pipeline of streaming data is presented. The pipeline is divided into multiple stages and buffer memories are inserted between adjacent stages. By dynamically changing the power state of each stage, the overall power consumption of the pipeline, including the power consumed by each stage and by each buffer, can be reduced. For example, when a buffer is full, the stage immediately before it can be turned off for a certain time period to save power. In this paper, the problem of finding the optimal strategy for managing the power state to minimize average power consumption is studied for a pipeline of data consisting of three stages with two buffers in between. The problem is formulated as an optimal control problem of a hybrid system, namely, a dynamical system with both continuous dynamics and discrete transitions. Several important properties of the optimal solutions are derived. Using these properties, the optimal periodic solutions are obtained analytically for the special case when each stage is allowed to turn on and off at most once during each period. Simulation results using practical data are presented. The results show substantial power savings of the proposed method over heuristic buffering strategies