'Pruned' Microchips Twice As Fast and Efficient

Zothecula writes "If you had to use a commuting bicycle in a race, you would probably set about removing the kickstand, fenders, racks and lights to make the thing as fast and efficient as possible. When engineers at Houston's Rice University are developing small, fast, energy-efficient chips for use in devices like hearing aids, it turns out they do pretty much the same thing. The removal of portions of circuits that aren't essential to the task at hand is known as 'probabilistic pruning,' and it results in chips that are twice as fast, use half the power, and are half the size of conventional chips."

Comments

Hm

[mewshi_nya]

It's news that removing unnecessary parts of a circuit make it more efficient? Really?

Re:Hm

[Shikaku]

I think the news is they developed a heuristic of least used parts of a chip, slapped on a tiny emulator so functions don't fail, and call it a day.

For example, Chip $foo has functions A B C D E & F. E is used on average once every gigaflop, so using the CPU/other functions, they implement E and cut out all parts for E.

Re:Hm

[Anonymous Coward]

I suppose everyone in the world is not already as intelligent and knowledgeable as you and might possibly find this interesting. Perhaps you could find it in your heart to allow the less intelligent and knowledgeable the opportunity to discover something like this so that then they will be as intelligent and knowledgeable as you. :-)

Re:Hm

[mikael]

They aren't cutting out entire blocks of ASIC circuitry in a Boolean keep or remove decision. They are sacrificing precision by reducing transistor count, and doing so in a somewhat heuristic approach in order to limit the loss of precision. Their algorithm will explore the worst case and best case of each arithmetic operation in order to achieve this. Not too different from the MiniMax approach to playing Chess or other board games.

Re:Hm

[mewshi_nya]

I actually know next to nothing about electronic circuits. I think the most complex thing I ever built was a metronome with variable tempo.

I would expect that almost everyone here would know this kind of stuff already...

Re:Hm

[Chelloveck]

For example, Chip $foo has functions A B C D E & F. E is used on average once every gigaflop, so using the CPU/other functions, they implement E and cut out all parts for E.

The best part is that this can be applied iteratively. Once E is eliminated there's a new "least used" function which can be eliminated. By extension, any CPU can ultimately be pruned down to a single NOP instruction, with the entire rest of the instruction set emulated in software.

Re:Hm

[Anonymous Coward]

"By extension, any CPU can ultimately be pruned down to a single NOP instruction, with the entire rest of the instruction set emulated in software."

Replace the CPU with a solar cell.

Not only can it perform NOPs at the same rate as any pruned CPU, but it also runs at a negative current draw when you open the lid (or if you have enough illuminated 'bling' fans installed).

Re:Hm

[ZankerH]

Already been done, it's called one instruction set computing, and it makes brainfuck look like python in comparison.

Now my computer won't start up!

[ClaraBow]

I was trying to make it more efficient by getting rid of some of the unused cores, so I got a pair of scissors and pruned off a couple of those cores. I put the pruned, aero dynamic chip back in my machine and now it won't start up! On the plus side, the power savings are noticeable :)

Slashdot cynics are right again

[russotto]

Someone's going to chime in and say that the naysayers are oversimplifying or denigrating this because they didn't think of it, but I think the quote below says enough.

"I believe this is the first time someone has taken an integrated circuit and said, 'Let's get rid of the part that we don't need,'" said principal investigator Krishna Palem, a Professor of Computing at Rice.

Uh, no, Professor, I don't believe it is.

That's fine ...

[PPH]

... for a specific application, like a hearing aid. Not so good for microprocessors intended for general purpose use (broad markets).

If you have sufficient market volume, you can afford to produce some sort of 'application specific integrate circuit'. Hmm, an ASIC. Now there's a novel idea (putting on jacket to make a dash to the patent office).

Madman Muntz famous(and rich)for this last century

[shoppa]

Removing unnecessary parts from a circuit until it stops working, is now something "new"?

From Wikipedia entry on Madman Muntz:

Muntz played the madman in his unorthodox television commercials, but in fact he was a shrewd businessman and a self-taught electrical engineer. By trial and error, taking apart and studying Philco, RCA, and DuMont televisions, he figured out how to reduce the devices' electrical components to their minimum functional number. This practice became known as "Muntzing".
He often carried a pair of wire clippers, and when he thought that one of his employees was "over-engineering" a circuit, he would begin snipping components out until the picture or sound stopped working. At that point, he would tell the engineer "Well, I guess you have to put that last part back in" and walk away.

erm

[DaveGod]

"I believe this is the first time someone has taken an integrated circuit and said, 'Let's get rid of the part that we don't need,'"

I believe this to be a basic part of design.

Re:Madman Muntz famous(and rich)for this last cent

[vadim_t]

Yeah, I'm not that crazy about that idea.

From what I gather the components being removed are most likely resistors and capacitors. And sure, some can be probably removed, if you don't mind ending up with a noisy power supply and too much current going to various parts.

So you're left with a device that kind of works, but that may mysteriously stop working in a few months.

Madman Muntz went bankrupt

[mangu]

What you didn't mention is that "Muntz admitted his business lost $1,457,000 from April to August 1953,[28] and although he tried to reorganize, Muntz TV filed bankruptcy and went out of business in 1959" (from the same Wikipedia article)

You see, engineers don't sprinkle components at random. Every component in an electronic circuit is there for a reason. If something can be removed, what you have is a defective specification, maybe your circuit is designed to perform a function that's not often used, maybe it's designed to function in a situation that never happens. In that case you can ask the engineer to redesign for looser specifications.

Removing components at random is just stupid.