ATAC: Ambient Temperature-Aware Capping for Power Efficient Datacenters

The emergence of cloud computing has created a demand for more datacenters, which in turn, has led to the substantial consumption of electricity by computing systems and cooling units. Although recently built warehouse-scale datacenters can nearly completely eliminate cooling overhead, small to medium datacenters, which still spend nearly half of their power on cooling, still labor under heavy cooling overhead. Often overlooked by the cloud computing community, these types of datacenters are not in the minority: They are responsible for more than 70% of the entire electrical power used by datacenters. Thus, to tackle the cooling inefficiencies of these datacenters, we propose ambient temperature-aware capping (ATAC), which maximizes power efficiency while minimizing overheating. ATAC senses the ambient temperature of each server and triggers a new performance capping mechanism to achieve 38% savings in cooling power and 7% savings in total power with less than 1% degradation in performance.