  This work studies the behavior of state-of-the-art memory controller designs
when executing scale-out workloads. It considers memory scheduling techniques,
memory page management policies, the number of memory channels, and the address
mapping scheme used. Experimental measurements demonstrate: 1)~Several recently
proposed memory scheduling policies are not a good match for these scale-out
workloads. 2)~The relatively simple First-Ready-First-Come-First-Served
(FR-FCFS) policy performs consistently better, and 3)~for most of the studied
workloads, the even simpler First-Come-First-Served scheduling policy is within
1\% of FR-FCFS. 4)~Increasing the number of memory channels offers negligible
performance benefits, e.g., performance improves by 1.7\% on average for
4-channels vs. 1-channel. 5)~77\%-90\% of DRAM rows activations are accessed
only once before closure. These observation can guide future development and
optimization of memory controllers for scale-out workloads.
