IBM Introduces Sleep Mode For Power Chips

IBM will be adding a new sleep mode to its Power processors that will essentially enable the chips to consume virtually no power when idle.

According to an IBM presentation at the Hot Chips conference at Stanford University in California on 23 Aug, the company will be adding what it is calling a deep sleep mode to its Power chips. The technology is code-named Winkle, according to reports.

That will be in addition to the three sleep modes that already exist in the Power7 processors, which were introduced earlier in 2010.

Nap Mode

Those modes are called nap, sleep and heavy sleep, and come into play depending on application workload demand. In each mode, the processor core draws a different amount of power when idle—less in the nap mode, more in the heavy sleep mode.

The tradeoff is that the deeper the sleep, the longer it takes for the chip to turn back on. However, even in the slowest mode, the latency is only a matter of milliseconds.

For example, in the nap mode, power to the chip core is reduced by 15 percent, and it can be brought back into operation almost immediately. Power in heavy sleep mode is cut by 85 percent, with a latency of 2 milliseconds when the chip is brought back into action.

In the new deep sleep mode, where power consumption is next to nil, it will take as long as 10 to 20 milliseconds for the chip to come back to life, according to a presentation at the show by Michael Floyd, an IBM engineer.

Data Centre Power Costs

Most chip makers, including Intel and Advanced Micro Devices, offer sleep modes in their processors as a way of reducing power consumption and increasing energy efficiency, efforts that are in demand from businesses looking to get control of spiraling data centre power costs. That demand is growing as enterprises increase their use of such technologies as virtualisation and cloud computing.

It is unclear when the Winkle mode will show up in IBM’s processors. According to reports, Floyd referred to it as a peek into IBM’s future. It could crop up in later versions of Power7, or after that in IBM’s future Power8 processors.