Power consumption is becoming a primary concern as a result of tremendous increasing in computer power usage. Innumerable methods and techniques have been exploited to address this problem but few concentrate on collaborative approaches. This paper presents coordination mechanisms that integrate operating systems with compilers under power reduction techniques such as DPM and DVS. By remaining the information generated at compile stage about an application’s structure and performance characteristics as much as possible and committing it to system software at run stage, the system software, especially the operation system and compiler, are collaborating toward file-grain power optimizations. The proposed coordination mechanisms also make it possible to integrate the power optimization approaches in our prior work into a whole system. Thus, the optimizations working at distinct levels can be overlaid at run time, and the power reduction effect can be enhanced.