Engineers propose method to eliminate wasted energy in computer processors

Mar 08, 2012

In today's computer processors, much of the power put into running the processor is being wasted.

A research team at Case Western Reserve University came up with a novel idea called fine-grained gating, which saves power and money in a couple of ways: less energy would be used, and less heat produced.

"Using less power produces less heat. Less heat means less cooling is needed," said Swarup Bhunia, professor of electrical engineering and science and an author of the research. "That can avoid the need for a big fan to cool off the processor, which saves a lot of money."

Processors are used in a variety of products, from computers to cell phones. Operational costs could be cut by more than one-third, the researchers say.

Bhunia, PhD student Lei Wang and PhD alumni Somnath Paul, whose work was funded by the Intel Corporation; presented their idea at the 25th International Conference on VLSI (Very-Large-Scale Integration) Design.

They received the award for best paper at the conference, held in Hyderabad, India Jan 7-11.

Bhunia explained that two parts of a processor consume power: the datapath and memory. The datapath performs computations and takes control decisions, while memory stores data.

The waste is built-in. Computing rarely requires everything that a processor is capable of all the time, but all of the processor is fully powered just the same.

For example, while the processor might not always be doing addition, the component that performs addition is still being powered.

One attempt to improve in processors is through something called coarse gating. It switches off an entire block of the processor that is not being used.

In the previous example, the coarse gating solution would be to just simply turn off the addition block when it is not doing addition.

The problem with this method is that most of the time, some part of every component is being used in a processor. Finding an entire block that is not being used at a given time is tough.

The Case Western Reserve team's fine-grained gating idea is to shut off only the parts of a component that are not being used at the time. While the addition component needs to be capable of adding extremely large numbers, it rarely needs to actually add large numbers. The processor might be using the addition block constantly, but the parts needed to add large numbers can be turned off most of the time.

Memory works the same way. A processor needs to be capable of storing large numbers, but seldom actually stores them.

This may not seem like much, but add everything up and it makes a big difference. The team calculated that the total power savings for a typical in a high-performance system, such as a desktop computer, would be about 40%.

Bhunia explained that fine gating can't be applied to current processors, but could be used by companies to build next generation processors.

This new method does not only help corporations though. With fine-grained gating, a smart phone battery that lasted eight hours could now more than 11.

That's three more hours of Angry Birds and Words with Friends, which is a win for everyone.

Explore further: Lifting the brakes on fuel efficiency

Related Stories

DonanimHaber leaks data on new AMD processors

May 17, 2011

( -- When it comes to the world of computer processors it is all about what it going to happen next. Even if the current generation of processors can do everything that you want them to that tantalizing ...

Intel updates Atom processor roadmap

May 18, 2011

( -- Intel is one the biggest names in PC processors, if not the single biggest, but as is the way with all markets as new things come in the landscape can change in the blink of an eye. When the ...

Intel Celeron D Processor Now Available

Jun 24, 2004

Intel Corporation today introduced the Intel® Celeron® D processor for desktop PCs. This processor line represents a new generation of Intel technology for desktop value market segments. Intel also unveiled ...

Intel® Pentium® 4 Processor on 90nm Technology

Apr 12, 2004

Intel has recently published an article called The Microarchitecture of the Intel® Pentium® 4 Processor on 90nm Technology. This paper describes the first Intel® Pentium® 4 processor manufactured on the 90nm process. It rev ...

Recommended for you

Lifting the brakes on fuel efficiency

Apr 18, 2014

The work of a research leader at Michigan Technological University is attracting attention from Michigan's Governor as well as automotive companies around the world. Xiaodi "Scott" Huang of Michigan Tech's ...

Large streams of data warn cars, banks and oil drillers

Apr 16, 2014

Better warning systems that alert motorists to a collision, make banks aware of the risk of losses on bad customers, and tell oil companies about potential problems with new drilling. This is the aim of AMIDST, the EU project ...

User comments : 9

Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (2) Mar 08, 2012
Having just heard this idea, how long it would take Intel to bring it to market?
not rated yet Mar 08, 2012
2-3 years
5 / 5 (3) Mar 08, 2012
2-3 years

"Bhunia explained that fine gating can't be applied to current processors, but could be used by companies to build next generation processors."
The next generation of processors, and associated architecture, still need to be developed. I say 3-5 years.
5 / 5 (2) Mar 08, 2012
Great idea but here is a simpler one that doesn't require processor re-design: Slap a heat-to-electricity conversion module on top of every processor and use it to trickle charge the battery. Simple, and it would do the same thing... recover some of that wasted heat and ultimately save on energy use.
5 / 5 (2) Mar 08, 2012
saves power... ...or creates more room for overclocking
5 / 5 (2) Mar 08, 2012
I don't understand what's new here, we've been using fine grained clock gating got many years.
Clock gating alone is indequate since significant power is consumed both in the gates and interconnect, and gating unused parts of the data-path is also common practice.
there are 2 main problems that have to be overcome and this doesn't address either of them.
first clock / signal gating requires additional gates which increase delays and consume power, so the power savings have to be worth inserting the gates.
secondly inserting gates into clock trees complicates clock tree balancing and these also require additional control logic to enable clocks during test.
The real issue is the complexity of design with fine grained clock gating, particularly for clock tree balancing and for test, these simply require better tools.
The real savings come from architectural design to minimize toggling without additional complex clock / signal gating.
5 / 5 (1) Mar 09, 2012
Very interesting approach. It seems they are not after clock gating. Instead they apply power gating to the unused part of the computing units such as the ALU and the memory. They seem to exploit data width (large or small) which is smart.
5 / 5 (5) Mar 09, 2012
I did this several years ago in low power GPS chipset design.
It's not a new idea, actually we went a lot futher by architecting the data processing to minimize toggling and using this to specifically create an architecture that allows more efficient gating for part of the datapath that is not required in real time.
5 / 5 (3) Mar 10, 2012
Based on my experience power gating for a general-purpose processor is different ball game. The nature of data is very different from that in specific applications. Looks like the work has addressed some important challenges. Well done!

More news stories

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

A homemade solar lamp for developing countries

( —The solar lamp developed by the start-up LEDsafari is a more effective, safer, and less expensive form of illumination than the traditional oil lamp currently used by more than one billion people ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...