A University of Washington project sees a role for programmers to reduce the energy appetite of the ones and zeroes in the code itself. Researchers have created a system, called EnerJ, that reduces energy consumption in simulations by up to 50 percent, and has the potential to cut energy by as much as 90 percent. They will present the research next week in San Jose at the Programming Language Design and Implementation annual meeting.
“We all know that energy consumption is a big problem,” said author Luis Ceze, a UW assistant professor of computer science and engineering. “With our system, mobile phone users would notice either a smaller phone, or a longer battery life, or both. Computing centers would notice a lower energy bill.”
The basic idea is to take advantage of processes that can survive tiny errors that happen when, say, voltage is decreased or correctness checks are relaxed. Some examples of possible applications are streaming audio and video, games and real-time image recognition for augmented-reality applications on mobile devices.
“Image recognition already needs to be tolerant of little problems, like a speck of dust on the screen,” said co-author Adrian Sampson, a UW doctoral student in computer science and engineering. “If we introduce a few more dots on the image because of errors, the algorithm should still work correctly, and we can save energy.”
The UW system is a general framework that creates two interlocking pieces of code. One is the precise part – for instance, the encryption on your bank account’s password. The other portion is for all the processes that could survive occasional slipups.
The software creates an impenetrable barrier between the two pieces.
“We make it impossible to leak data from the approximate part into the precise part,” Sampson said. “You’re completely guaranteed that can’t happen.”
While computers’ energy use is frustrating and expensive, there is also a more fundamental issue at stake. Some experts believe we are approaching a limit on the number of transistors that can run on a single microchip. The so-called “dark silicon problem” says that as we boost computer speeds by cramming more transistors onto each chip, there may no longer be any way to supply enough power to the chip to run all the transistors.
The UW team’s approach would work like a dimmer switch, letting some transistors run at a lower voltage. Approximate tasks could run on the dimmer regions of the chip.
“When I started thinking about this, it became more and more obvious that this could be applied, at least a little bit, to almost everything,” Sampson said. “It seemed like I was always finding new places where it could be applied, at least in a limited way.”
Researchers would use the program with a new type of hardware where some transistors have a lower voltage, the force on electrons in the circuit. This slightly increases the risk of random errors; EnerJ shuttles only approximate tasks to these transistors.
“If you can afford one error every 100,000 operations or so, you can already save a lot of energy,” Ceze said.
Other ways to use hardware to save energy are lowering the refresh rate and reducing voltage of the memory chip.
Simulations of such hardware show that running EnerJ would cut energy by about 20 to 25 percent, on average, depending on the aggressiveness of the approach. For one program the energy saved was almost 50 percent. Researchers are now designing hardware to test their results in the lab.
Today’s computers could also use EnerJ with a purely software-based approach. For example, the computer could round off numbers or skip some extra accuracy checks on the approximate part of the code to save energy – researchers estimate between 30 and 50 percent savings based on software alone.
Combining the software and hardware methods they believe they could cut power use by about 90 percent.
“Our long-term goal would be 10 times improvement in battery life,” Ceze said. “I don’t think it is totally out of the question to have an order of magnitude reduction if we continue squeezing unnecessary accuracy.”
The program is called EnerJ because it is an extension for the Java programming language. The team hopes to release the code as an open-source tool this summer.
Co-authors of the paper are UW computer science and engineering professor Dan Grossman, postdoctoral researcher Werner Dietl, graduate student Emily Fortuna and undergraduate Danushen Gnanapragasam. Also involved in the research is doctoral student Hadi Esmaeilzadeh.
For more information, contact Ceze at email@example.com or 206-543-1896 and Sampson at firstname.lastname@example.org or 206-659-7267.
See also the research paper, "EnerJ: Approximate data types for safe and general low-power computation."
Hannah Hickey | EurekAlert!
Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH
To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences