Understanding power-performance relationship of energy-efficient modern DRAM devices

As servers are equipped with more memory modules each with larger capacity, main-memory systems are now the second highest energy-consuming component in big-memory servers and their energy consumption even becomes comparable to processors in some servers. Meanwhile, it is critical for big-memory servers and their main-memory systems to offer high energy efficiency. Prior work exploited mobile LPDDR devices' advantages (lower power than DDR devices) while attempting to surmount their limitations (longer latency, lower bandwidth, or both). However, we demonstrate that such main memory architectures (based on the latest LPDDR4 devices) are no longer effective. This is because the power consumption of present DDR4 devices has substantially decreased by adopting the strength of mobile and graphics memory whereas LPDDR4 has sacrificed energy efficiency and focused more on increasing data transfer rates; we also exhibit that the power consumption of DDR4 devices can substantially vary across manufacturers. Moreover, investigating a new energy-saving feature of DDR4 devices in depth, we show that activating this feature often hurts overall energy efficiency of servers due to its performance penalties.

[1]  Hyeontaek Lim,et al.  MICA: A Holistic Approach to Fast In-Memory Key-Value Storage , 2014, NSDI.

[2]  Mark Horowitz,et al.  Rethinking DRAM Power Modes for Energy Proportionality , 2012, 2012 45th Annual IEEE/ACM International Symposium on Microarchitecture.

[3]  Babak Falsafi,et al.  Clearing the clouds: a study of emerging scale-out workloads on modern hardware , 2012, ASPLOS XVII.

[4]  Christoforos E. Kozyrakis,et al.  Towards energy-proportional datacenter memory with mobile DRAM , 2012, 2012 39th Annual International Symposium on Computer Architecture (ISCA).

[5]  Bruce Jacob,et al.  The Memory System: You Can't Avoid It, You Can't Ignore It, You Can't Fake It , 2009, The Memory System: You Can't Avoid It, You Can't Ignore It, You Can't Fake It.

[6]  Luiz André Barroso,et al.  The Datacenter as a Computer: An Introduction to the Design of Warehouse-Scale Machines , 2009, The Datacenter as a Computer: An Introduction to the Design of Warehouse-Scale Machines.

[7]  Jichuan Chang,et al.  BOOM: Enabling mobile memory based low-power server DIMMs , 2012, 2012 39th Annual International Symposium on Computer Architecture (ISCA).