Toward Server Efficiency in the Post-Dennard Era2015-2016
The popularity of online services drives the need for bigger datacenters with more server processors. As Moore’s law continues, the number of transistors on chip rises exponentially, enabling us to have CMPs with hundreds of cores. However, due to the slowdown in Dennard’s scaling, we cannot power up all of them at the same time. Hence, soon we will enter an era of “dark silicon”, in which we cannot power up fast and dense processors. In this work, we explore the potential directions to improve the energy efficiency of server processors in the post-Dennard era. Moreover, we investigate the hardware- and software-related constraints of designing a server processor for modern cloud services, and we propose an approach based on near-threshold computing (NTC) to design energy efficient server processors. We propose an architecture based on the FD-SOI process technology for NTC in servers. Our study demonstrates the benefits of NTC and proposes several directions to synergistically increase the energy proportionality of a near-threshold server.