Just a quick note that AMD rolled out a new mining driver for Linux users. You can download the AMDGPU-PRO Beta Mining Driver 17.40 beta over here. This version adds Large Page Support for Blockchain Compute Workloads and should improve Ethereum hashrates:
Introduces Large Page Support for Blockchain Compute Workloads. This driver is provided as a beta level support driver which should be considered "as is" and will not be supported with further updates, upgrades or bug fixes. This driver is not intended for graphics or gaming workloads.