Search

Dynamic power management saves power by shutting down idle devices. Several management algorithms have been proposed and demonstrated to be effective in certain applications. We quantitatively compare the power saving and performance impact of these algorithms on hard disks of a desktop and notebook computers. This paper has three contributions. First, we build a framework in Windows NT to implement power managers running realistic workloads and directly interacting with users. Second, we define performance degradation that reflects user perception. Finally, we compare power saving and performance of existing algorithms and analyze the difference.

The power dissipated by system-level buses is the largest contribution to the global power of complex VLSI circuits. Therefore, the minimization of the switching activity at the I/O interfaces can provide significant savings on the overall power budget. This paper presents innovative encoding techniques suitable for minimizing the switching activity of system-level address buses. In particular, the schemes illustrated here target the reduction of the average number of bus line transitions per clock cycle. Experimental results, conducted on address streams generated by a real microprocessor, have demonstrated the effectiveness of the proposed methods.