Impacts of Indirect Blocks on Buffer Cache Energy Efficiency

Indirect blocks, part of a file's metadata used for locating this file's data blocks, are typically treated indistinguishably from file's data blocks in buffer cache. This paper shows that this conventional approach will significantly detriment the overall energy efficiency of memory systems. Scattering small but frequently accessed indirected blocks over allmemory chips reduce the energy saving opportunities. We propose a new energy-efficient buffer cache management scheme, named MEEP, which separates indirect and datablocks into different memory chips. Our trace-driven simulation results show that our new scheme can save memory energy up to 16.8% and 15.4% in the I/O-intensive server workloads TPC-R and TPC-H, respectively.