2018 Volume 15 Issue 3 Pages 20171253
A major hurdle to adopt 3D stacked DRAM is a thermal problem particularly when the DRAM dies are stacked above the processor dies. Exacerbated thermal problems in DRAM cause another problem which increases refresh rates to ensure data integrity of DRAM cells. In this paper, we propose two efficient techniques to address the thermal problem in 3D die-stacked DRAM by suppressing adverse thermal impacts from the processor die. Our thermal-aware task mapping technique allocates tasks to cores by considering computation-intensiveness of the workloads to minimize thermal interactions. The workload-aware core pipeline control technique adjusts pipeline widths (fetch and issue widths) of processor cores considering the workload characteristics. By adopting our proposed techniques, system-wide energy consumption is reduced by 7.6% while improving performance by 0.4% on average, thanks to the reduced pipeline widths and refresh rates. In terms of temperature, our techniques reduce the number of DRAM banks which exceed 85 degree Celsius by 92.8%, on average.