In the words of Professor Martin Karsten, “Almost every single service request that happens on the Internet could be positively affected by this.” Karsten is an Associate Director at the Cheriton School of Computer Science. “This” is a few lines of code that he has pioneered to be added to the Linux operating system.
Linux is used by companies like Amazon and Google to power their platforms. Whether or not we’re aware of it, we all interact with Linux countless times a day. And thanks to Karsten’s new code, the amount of energy it takes to access these websites will be reduced by up to 30 percent. These few lines of code could lead to a five percent reduction in how much energy data centres use worldwide.
Data centres: a drain on our resources
Data centres house computers which store our online data and power the digital world. They’re also responsible for between two to three percent of global electricity consumption—and it’s predicted that our usage of data centre power will grow six-fold in the next decade.
Renewable energy sources, innovative solutions and, of course, optimisation of operation systems, are all ways to reduce the emissions of data centres.
How the code came to life
From 2022 to 2023, Karsten was working alongside his former Master’s student Peter Cai. Their research included analysing performance observations in literature about user-level network stack processing (a system setup where data packets bypass the kernel network stack and are instead implemented as part of the application). “While doing this work, we discovered that a particular processing pattern is highly beneficial,” Karsten explained to RESET. “We realised that the same mechanism is possible with the Linux kernel.”
Interrupt request suspension—or IRQ Suspend—is the solution they developed. It allows Linux to adapt to the amount of incoming traffic. This means that the operating system sleeps when it’s not needed, which reduces the energy consumption of data centres. According to Karsten, “This results in the best of both worlds. High efficiency and performance during peak periods and power savings during idle periods.”
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Linux adopts the code
To write the code, Karsten worked with Joe Damato, Distinguished Engineer at Fastly. After submitting the code to Linux for consideration in November 2024, it has now been adopted in their latest release, version 6.13. As there’s a time lag between releases and distribution, there isn’t yet concrete data on the impact of the new code. “But what I’ve heard so far sounds very encouraging,” Karsten tells us.
When systems become more efficient, there is a risk that our usage will increase, negating any energy-saving benefits. This is known as the Jevons paradox. Karsten concedes that this could apply to the newly efficient Linux system; he highlights the need for mindful usage of digital tools and optimising efficiency. “Crypto-mining is a prime example of expensive and useless computations that waste energy for absolutely no benefit.” Meanwhile, many other inefficiencies in modern software need to be tackled. “Investigating these will be my primary research topic for the foreseeable future.”
