Sacrificing Accuracy For Speed and Efficiency In Processors

Skudd writes "Modern computing has always been reliant on accuracy and correct answers. Now, a professor at Rice University in Houston posits that some future applications could be revolutionized by 'probabilistic computing.' Quoting: 'This afternoon, Krishna Palem, speaking at a computer science meeting in San Francisco, will announce results of the first real-world test of his probabilistic computer chip: The chip, which thrives on random errors, ran seven times faster than today's best technology while using just 1/30th the electricity. ... The high density of transistors on existing chips also leads to a lot of background "noise." To compensate, engineers increase the voltage applied to computer circuits to overpower the noise and ensure precise calculations. Palem began wondering how much a slight reduction in the quality of calculations might improve speed and save energy. He soon realized that some information was more valuable than other information. For example, in calculating a bank balance of $13,000.81, getting the "13" correct is much more important than the "81." Producing an answer of $13,000.57 is much closer to being correct than $57,000.81. While Palem's technology may not have a future in calculating missions to Mars, it probably has one in such applications as streaming music and video on mobile devices, he said.'

Comments

Re:Bank balance

[CastrTroy]

I agree. The whole problem with the example given in the summary is that your bank balance should never be wrong. There is no room for error in calculating bank balances. I also don't want to hear skips and pops in my music because they though it would be more energy efficient to use a processor that produced errors. I already get 26 hours of charge out of my MP3 player. I'd rather have them focus on getting more space for cheaper so I can carry lossless audio on my portable mp3 player.

Re:Bank balance

[BadAnalogyGuy]

If you are listening to music on a portable media device, it's safe to say that you aren't going to be able to hear the difference between the lossy format and the lossless format.

It's like drinking from a well. Connoisseurs may claim to be able to taste the difference between it and tap water, but that's just the extra tang from all the bull shit.

It seems like when you need a precise calculation

[rolfwind]

like financial things, you compare the end product with the end product of the same calculation run either through the chip again or another chip (or increasingly likely another core).

Still would be faster too.

gfx

[RiotingPacifist]

can't this be used in gfx cards, i mean with anti-aliasing and high resolutions it doesn't really matter so much if 1/2 a pixel is #ffffff or #f8f4f0 , hell you can probably even get a pixel entirely wrong for one frame and nobody will care (as long as it doesn't happen too often).

Re:DSP's?

[Firethorn]

I think the point would be using a DSP/math coprocessor that uses 1/30th the power in exchange for a .001% loss in accuracy for non-essential tasks like music decoding.

I mean, combined with the lousy earbuds most people use, who'd notice? Especially if it makes their MP3 player last 3 times as long as ones that use more traditional and technically accurate DSP/decoder?

Re:Bank balance

[Hojima]

There are countless applications for a computer that don't depend on accuracy, but do depend on speed. For example: gaming, stock analysis, scientific/mathematical research etc. Just about every use for the computer can benefit from this. Bear in mind these applications can take the hit of inaccuracy, if not benefit from it depending on the situation. Yes there are some instances were accuracy is crucial, but that's why they will continue to make both of the processors. It's what they call a free market, and there will be always be a new niche to fill.

Re:Bank balance

[memco]

Ok, so not only do I have to give up efficiency in the chip itself, but now my efficiency suffers because I now have to determine which chips are useful for which applications. I don't want to have to start thinking about whether or not I plan to use my new laptop for anything requiring accuracy greater than such and such a percentage. I suppose this might be effective for niche markets, but it seems messy if you try to make it part of all computing platforms.