University of Idaho
As increasingly larger memories are used to bridge the widening gap between processor and disk speeds, main memory energy consumption is becoming increasingly dominant. Even though much prior research has been conducted on memory energy management, no study has focused on data servers, where main memory is predominantly accessed by DMAs instead of processors. In this paper, the authors study DMA-aware techniques for memory energy management in data servers. They first characterize the effect of DMA accesses on memory energy and show that, due to the mismatch between memory and I/O bus bandwidths, significant energy is wasted when memory is idle but still active during DMA transfers.