Operating system 'tweak' could cut data centre power consumption by 25 per cent

Simultaneous multi-threading can make servers handle instructions more efficiently - if only operating systems would use it

A simple tweak to operating systems could reduce the power consumption of large data centres by as much as 25 per cent, according to researchers at the Australian National University, working with Microsoft.

"Computer servers spend a lot of time waiting around for search requests to come in. By sneaking in other processes while they are waiting, we can use the computers more efficiently," said Professor Steve Blackburn from ANU Research School of Computer Science.

While major internet companies now have massive server farms tuned to provide fast responses rather than efficiency - whether for simple web searches or complex applications running in the cloud, much of that capacity is idle and only used to cover spikes in demand. "The companies have no control of when users will request a search, so they have large server capacity that is mostly idle," said Xi Yang, a PhD student at the ANU Research School.

Yang collaborated with Professor Blackburn and Dr Kathryn McKinley at Microsoft to work out a way for processes that are not time critical to use the operating system while it is idle, and to quickly step out of the way when search requests come in. "The techniques are extremely easy to implement on current hardware," claimed Yang.

He added: "In some cases that we studied, the new techniques made a server nine times more efficient."

The core concept that the team examined was to analyse server and application performance in granular detail so that extra processes could be slipped-in while longer processes were awaiting instructions.

"We have analysed the operating system's performance 100 times more closely than before, which is crucial, because much of the activity that occurs inside a computer happens at very high frequencies," said Yang.

Microsoft's McKinley suggested that while high-end hardware offered a technique called ‘simultaneous multi-threading', "many companies turn off this feature, because without our approach, sharing wreaks havoc with the responsiveness of interactive services, such as searches. With our new fine grain control hardware control, we can substantially improve the efficiency of data centre servers while achieving the same responsiveness," she said.

"This work has the potential for enormous impact in data centres - it could save over 25 per cent of the data centre energy bill for these companies, a huge win," she added.

Professor Blackburn said that the idea was originally inspired by the fairy tale of the Elves and the Shoemaker. "It's just like the elves that used the shoemaker's tools at night in the Brothers Grimm fairy tale."