TUE, a New Energy-Efficiency Metric Applied at ORNL’s Jaguar

The metric, Power Usage Effectiveness (PUE), has been successful in improving energy efficiency of data centers, but it is not perfect. One challenge is that PUE does not account for the power distribution and cooling losses inside IT equipment. This is particularly problematic in the HPC (high performance computing) space where system suppliers are moving cooling and power subsystems into or out of the cluster. This paper proposes two new metrics: ITUE (IT-power usage effectiveness), similar to PUE but “inside” the IT and TUE (total-power usage effectiveness), which combines the two for a total efficiency picture. We conclude with a demonstration of the method, and a case study of measurements at ORNL’s Jaguar system. TUE provides a ratio of total energy, (internal and external support energy uses) and the specific energy used in the HPC. TUE can also be a means for comparing HPC site to HPC site.