The Price of Meltdown and Spectre: Energy Overhead of Mitigations at Operating System Level

Abstract

The Meltdown and Spectre hardware vulnerabilities shocked hardware manufacturers and system users upon discovery. Numerous attack vectors and mitigations have been developed and deployed. However, due to the deep entanglement in core CPU components they will be an important topic for years. Although the performance overhead of software mitigations has been examined closely, the energy overhead has experienced little attention---even though the energy demand is a critical cost factor in data centres. This work contributes a fine-grained energy-overhead analysis of Meltdown/Spectre software mitigations, which reveals application-specific energy overheads of up to 72 %. We further compare energy overheads to execution time overheads. Additionally, we examine subsystem-specific effects (i.e., CPU, memory, I/O, network/interprocess communication) and develop a model that predicts energy overheads for applications.