New tweak to Linux kernel could cut data center power usage by up to 30%

An improvement to the way Linux handles network traffic, developed by researchers at Canada’s University of Waterloo, could make data center applications run more efficiently and save energy at the same time.

Waterloo professor Martin Karsten and Joe Damato, distinguished engineer at Fastly, developed the code — approximately 30 lines. It’s based on research described in a 2023 paper, written by Karsten and grad student Peter Cai, that investigated kernel versus user-level networking and determined that a small change could not only increase application efficiency, but cut data center power usage by up to 30%.

The new code was accepted and added to version 6.13 of the Linux kernel. It adds a new NAPI configuration parameter, irq_suspend_timeout, to help balance CPU usage and network processing efficiency when using IRQ deferral and napi busy poll. This allows it to automatically switch between two modes of delivering data to an application — polling, and interrupt-driven — depending on network traffic, to maximize efficiency.