Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

worrydream.com

Post reply on HN
Print view View original

11–20 of 31 posts

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#11

Post by nickpsecurity »

B1FF_PSUVM wrote: post #9
wmf wrote: post #4

Asynchronous logic is significantly more power efficient, so it may be one approach to "save Moore's Law" (for one generation perhaps). But it would probably require some company that really cares about power efficiency, doesn't care about industry best practices, and is willing to risk hundreds of millions in R&D.

People have been poking at it for over 30 years now. I'm scratching it up to "it's the future, and always will be ..."

Achronix Semiconductor used it for cutting-edge, 1+GHz FPGA's. Check them out.

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#12

Post by sliverstorm »

B1FF_PSUVM wrote: post #9
wmf wrote: post #4

Asynchronous logic is significantly more power efficient, so it may be one approach to "save Moore's Law" (for one generation perhaps). But it would probably require some company that really cares about power efficiency, doesn't care about industry best practices, and is willing to risk hundreds of millions in R&D.

People have been poking at it for over 30 years now. I'm scratching it up to "it's the future, and always will be ..."

The industry might hit the point one day, but for now it seems to fall in the bucket of "modest payoff, very very very high cost".

The upsides are real but other avenues of development may still have higher payoff vs cost (effort).

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#13

Post by trsohmers »

effie wrote: post #5

This reminded me of one of Gustafson's reasoning for change in how numerical computations are done - currently used principles of hw architecture result in hw wasting lots of energy and time, mostly in the process where numbers get from RAM to CPU and back. It seems more people already realize this, which is good. I hope to see some general purpose hw inspired by these ideas of efficient computation.

The inefficiency you are talking about is not due to the fact that there is a synchronous clock (within each individual "block", since there needs to be some async logic going between the different clock domains of DRAM and the processor). The waste in getting numbers from RAM to the register file is primarily due to the hardware managed cache hierarchy, which we are addressing at REX Computing, along with John Gustafson as an advisor.

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#14

Post by wnoise »

wmf wrote: post #4

Asynchronous logic is significantly more power efficient, so it may be one approach to "save Moore's Law" (for one generation perhaps). But it would probably require some company that really cares about power efficiency, doesn't care about industry best practices, and is willing to risk hundreds of millions in R&D.

Most of the money would be in development, not research. Elegant designs and methods exist, and the designs can be iterated very quickly. The very real problem has been interfacing with the rest of the world. Not at the hardware level (see the switch designs mentioned elsewhere in this thread), but in the interoperability of design software and other tools. Any company will need either their own design software, or to do a massive hack-job to get synchronous design software to work well without that bedrock assumption.

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#15

Post by marcosdumay »

B1FF_PSUVM wrote: post #9
wmf wrote: post #4

Asynchronous logic is significantly more power efficient, so it may be one approach to "save Moore's Law" (for one generation perhaps). But it would probably require some company that really cares about power efficiency, doesn't care about industry best practices, and is willing to risk hundreds of millions in R&D.

People have been poking at it for over 30 years now. I'm scratching it up to "it's the future, and always will be ..."

People have been poking at every architecture improvement for 30 years. Moore's Law makes it clear that the only winning move is to go into the most popular path.

Now that Moore's Law is on its way out, people can actually try new things, and discover what pays off and what does not.

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#16

Post by phkahler »

>> Imagine what software would be like if subroutines could start and end only at preset time intervals. “My subroutines all start at 3.68 millisecond intervals; how often do yours start?”

Mine start at 50 microsecond intervals. I've worked on stuff with shorter and longer intervals. Sometimes we have lists of tasks that need to run at different rates, so scheduling becomes a real pain. Welcome to the world of real time embedded software in high performance systems. The same thing applies, we make sure the worst case execution time is within the allowed intervals and use a master clock to sync everything up.

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#17

Post by Razengan »

marcosdumay wrote: post #15
B1FF_PSUVM wrote: post #9

Earlier quoted context omitted.

People have been poking at it for over 30 years now. I'm scratching it up to "it's the future, and always will be ..."

People have been poking at every architecture improvement for 30 years. Moore's Law makes it clear that the only winning move is to go into the most popular path. Now that Moore's Law is on its way out, people can actually try new things, and discover what pays off and what does not.

This could also be a chance to figuratively reboot computing tech, and start anew from different fundamentals: quaternary, biological, photonic...

What may have been hard to implement 30-40 years ago may be easier now with current technology. Some of these could definitely supplement existing binary/boolean silicon in certain domains if not replace it, like using actual brains in AI-as-a-Service, for image recognition and so on,

Re: The Tyranny of the Clock – Ivan Sutherland (2012) [pdf]

#18

Post by jacquesm »

phkahler wrote: post #16

>> Imagine what software would be like if subroutines could start and end only at preset time intervals. “My subroutines all start at 3.68 millisecond intervals; how often do yours start?” Mine start at 50 microsecond intervals. I've worked on stuff with shorter and longer intervals. Sometimes we have lists of tasks that need to run at different rates, so scheduling becomes a real pain. Welcome to the world of real t…

I've done quite a few of these embedded systems with real time constraints and your summary is quite accurate. The good part for me is that once you have things nailed down they (usually, and if not then you're really in for a long night) don't shift and what works will continue to work reliably.

This in contrast to non-real-time systems which tend to just freeze for random periods of time (sometimes seconds or even minutes) without any apparent cause. That's something that really puzzles me about todays software+hardware. In theory it should all be faster than ever but in practice I spend as much or even more time waiting for my computers than I ever did in the past.

Maybe I'm just more impatient but I don't believe that's the reason here.

Real time should be the norm, not the exception, just like encrypted communications should be the norm, not the exception.

Computers should respond without noticeable latency to user input at all times.

Post reply on HN