PS-BC: Power-saving considerations in design of buffer caches serving heterogeneous storage devices

Under a replacement policy, existing operating systems identify and maintain most frequently used storage data in buffer caches located in main memory, aiming at low-latency I/O data accesses. However, replacement policies can also strongly affect energy consumptions of various connected storage devices, which has not been a consideration in the design and implementation of buffer cache management. In this paper, we present a system framework for an energy-aware buffer cache replacement, called PS-BC (power-saving buffer cache). By considering several critical factors affecting system energy consumption, PS-BC can effectively improve system energy efficiency, while it is able to flexibly incorporate conventional performance-oriented buffer cache replacement policies for different performance objectives. Our experimental studies based on a trace-driven simulation show that the PS-BC framework embedded with the CLOCK replacement policy can achieve an energy saving rate of up to 32.5% with a minimal overhead for various workloads.