PowerNap Targets Server Idle Time update from March 2009

There's been some buzz this week about a new research paper outlining an approach to reduce the amount of power used when servers are idle. Researchers at Carnegie Mellon and the University of Michigan use the phrase "PowerNap" to describe the cost savings that could be achieved if servers' power usage could be dramatically lowered when they become idle. The paper (PDF) provides some interesting detail on the power being used by idle servers, which they have used to suggest the potential for some eye-popping savings - which in turn has generated coverage from eWeek, Greener Computing, Pete Sacco and Dave Ohara, who links to an associated podcast.

The catch? It will take some work to capture those savings. The hardware mechanisms required to manage server idle power usage "are omitted in current-generation server class components." There's also the matter of the operating system. "For schemes like PowerNap, the periodic timer interrupt used by legacy OS kernels to track the passage of time and implement software timers poses a challenge. As the timer interrupt is triggered every 1ms, conventionalOS time keeping precludes the use of PowerNap." The researchers say the Linux kernel has recently been enhanced to support the necessary “tickless” operation.