Microsoft researchers have slashed desktop energy use with a sleep proxy system that maintains a PC's network presence even when it is turned off or put into standby mode.
Microsoft has deployed the sleep proxy system to more than 50 active users in the Building 99 research facility in Redmond, Wash., according to the Microsoft Research Web site and a paper that will be presented at the Usenix technical conference in Boston later this month.
"A number of studies have noted that most office machines are left on irrespective of user activity," Microsoft researchers write in a paper titled "Sleepless in Seattle no longer." "At Microsoft Research, we find hundreds of desktop machines awake, day or night – a significant waste of both energy and money. Indeed, potential savings can amount to millions of dollars per year for larger enterprises."
Sleep proxies allow machines to be turned off while keeping them connected to the network, waking the machines when a user or IT administrator attempts to access it remotely.
Microsoft's research group isn’t the first to work on a sleep proxy – or even the only one presenting sleep proxy research at Usenix – but Microsoft contends that most previous work has evaluated sleep proxies only in small testbeds or simulations.
"We are not aware of any paper detailing the deployment of any of these proxying solutions in an operational enterprise network on actual user machines," Microsoft said. "This is disconcerting: systems that work well on testbeds often encounter potentially serious challenges when deployed in operational networks."
Microsoft's sleep proxy system has been operational for most of the past year, with software deployed on users' primary workstations. So far, the system has allowed user machines to sleep more than 50% of the time, but Microsoft hopes to increase that number by minimizing "interference from IT management tasks."
Microsoft's Sleep Proxy system is based on two components: server-side software called SleepServer, and SleepNotifier, which runs on client machines.
"SleepNotifier alerts SleepServer just before the client goes to sleep, and SleepServer ensures that all incoming traffic meant for the client comes to the proxy instead," Microsoft writes in another article titled "Trying to cure PC insomnia." "The proxy server's role is to monitor traffic and respond accordingly. For some requests, it responds on behalf of the client so the client can continue sleeping, and others it ignores. Some traffic, such as a user access request, causes the SleepServer proxy to awaken the client and present the user with apparently seamless remote access."
Although Microsoft is using the system with Windows, it is designed to be agnostic to the operating system.
The SleepServer component is described by a separate group of researchers from the University of California, San Diego, who will also present a paper at Usenix.
The paper, titled "SleepServer: A Software-Only Approach for Reducing the Energy Consumption of PCs within Enterprise Environments," says energy savings from the system should range from 60% to 80%.
Desktops provide a bigger target for energy savings than laptops, because laptops consume less power when active and are more often put to sleep by users, Microsoft researchers said. In modern buildings, 50% to 80% of electricity used can be attributed to IT equipment, particularly desktops, the UC-San Diego researchers said.
Cloud computing may help reduce energy use in desktops and mobile clients, however, according to two other research papers that will be presented at Usenix.
One Usenix paper, "The Case for Energy-Oriented Partial Desktop Migration," looks at migrating idle desktop sessions to the cloud to reduce energy costs. A second paper, "Energy Efficiency of Mobile Clients in Cloud Computing," measures energy use of mobile handheld devices and discusses "implications for the design and engineering of energy efficient mobile cloud computing solutions."
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