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Moore’s Law Is About to Get Weird (2015)

nautil.us

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Re: Moore’s Law Is About to Get Weird (2015)

#11

Post by chii »

ansible wrote: post #5

Well, none of those listed technologies is practical. Ternary logic is really cool, but it only gets you about a 10% efficiency improvement. I think it would be awesome to go in this direction, but retooling our entire tech stack for that isn't going to happen. I mean, look at x86. The only thing that will really make progress is molecular nanotechnology. I had always believed that reaching the end of silicon process…

if Intel has reasonable guesses as to what their competitor's level of R&D is at, they can stall the current gen tech for as long as possible, in order to milk the max profits off the capital investments.

Chip design and manufacturing isn't something a garage tinkerer can do (at the level of cutting edge research to compete with existing silicon makers). Therefore, companies like Intel can afford to lax until their customers demand differently (in which case, they will probably put the gas on R&D).

Re: Moore’s Law Is About to Get Weird (2015)

#12

Post by n00b101 »

api wrote: post #7

One thought that isn't on here: Once the process is "mature" and isn't changing every few years, the error rate could be squeezed way down. That would make it practical and economical to make larger chips. There are cooling and power issues too but I'm sure those are solvable. Make way for the 64-bit 128-core 1024gb RAM 12cm^2 SoC? Call it More's Law? Or a BFC? (for Big F'ing Chip?)

>Make way for the 64-bit 128-core 1024gb RAM 8cm^2 SoC

This is already happening?

Intel Xeon Knights Landing already has an enormous 6.83cm^2 die size. It has 72 "cores," each of which has a 512-bit vector processor. In some sense, you could say that this chip has 9,216 "single precision cores." It also supports up to 384GB DDR4 RAM, which is not far from your 1024GB.

The term "core" is becoming vague, as NVIDIA refers to thousands of "CUDA cores" on its GPUs which are really vector processor elements.

China's Sunway SW26010 is also kind of a "SoC," 260 "cores" communicating via a Network-on-Chip interconnect. I think one could say that the Cell Broadband Engine processor had a similar design.

> make it practical and economical to make larger chips

I do wonder if die sizes can increase.

I'm not a hardware engineer, but my understanding is that latency is the main barrier to larger chips. The time it takes for a signal to propagate across a chip limits the clock frequency. One possibility is to replace the global synchronous clock design with an asynchronous chip design. However, from what I understand, this would make things worse because some form of synchronization is always needed - you could send back an "acknolwedge" message, but that would double the signal traffic.

On the other hand, supercomputers are regularly built with multi-socket systems and interconnects like QPI and PCIe between processors and nodes. It would seem logical to put multiple processors their interconnects on a single "SoC" and I don't know why that doesn't happen. Maybe it is because of error rates, as you say.

Re: Moore’s Law Is About to Get Weird (2015)

#13

Post by adwn »

api wrote: post #7

One thought that isn't on here: Once the process is "mature" and isn't changing every few years, the error rate could be squeezed way down. That would make it practical and economical to make larger chips. There are cooling and power issues too but I'm sure those are solvable. Make way for the 64-bit 128-core 1024gb RAM 12cm^2 SoC? Call it More's Law? Or a BFC? (for Big F'ing Chip?)

It's a lot more practical to put several dies insides one package, which is already happening (for example, the largest FPGAs from Xilinx have 4 dies in a single package). Intra-package communication is not quite as good as intra-die communication (from a performance and energy point of view), but it's a lot better than inter-package communication, and several small dies have a higher yield than one large die.

Re: Moore’s Law Is About to Get Weird (2015)

#14

Post by swalsh »

ansible wrote: post #5

Well, none of those listed technologies is practical. Ternary logic is really cool, but it only gets you about a 10% efficiency improvement. I think it would be awesome to go in this direction, but retooling our entire tech stack for that isn't going to happen. I mean, look at x86. The only thing that will really make progress is molecular nanotechnology. I had always believed that reaching the end of silicon process…

"retooling our entire tech stack for that isn't going to happen. I mean, look at x86."

I wonder if today it's easier than people imagine, but the lessons of Itanium are used as a signal to not try.

Sure there are plenty of apps which make low-level use of x86 features, and those probably aren't going to be updated. However a lot of modern software is written in languages that go through interrupters. Java, C#, Python.. if you can update the runtime, in theory the apps can be supported anywhere.

Re: Moore’s Law Is About to Get Weird (2015)

#15

Post by adrianN »

TheArcane wrote: post #6

What about Quantum computing?

Quantum computing is still in the "researchers are playing with a handful of Qbits" stage, approximately where transistors where a hundred years ago. Scaling quantum computers is really hard. Even though Qbits can be encoded in single atoms, the machinery that keeps the quantum states stable and manipulates them is most definitely not easy to shrink.

It's also completely unclear whether quantum computers would make your Javascript engine run any faster.

Re: Moore’s Law Is About to Get Weird (2015)

#17

Post by pjc50 »

swalsh wrote: post #14
ansible wrote: post #5

Well, none of those listed technologies is practical. Ternary logic is really cool, but it only gets you about a 10% efficiency improvement. I think it would be awesome to go in this direction, but retooling our entire tech stack for that isn't going to happen. I mean, look at x86. The only thing that will really make progress is molecular nanotechnology. I had always believed that reaching the end of silicon process…

"retooling our entire tech stack for that isn't going to happen. I mean, look at x86." I wonder if today it's easier than people imagine, but the lessons of Itanium are used as a signal to not try. Sure there are plenty of apps which make low-level use of x86 features, and those probably aren't going to be updated. However a lot of modern software is written in languages that go through interrupters. Java, C#, Python…

Switching to ternary means retooling not just the programming stack but the IC design stack. IC design is actually quite a conservative business, mainly because failures are so expensive.

You'd need to spend several years writing a ternary RTL synthesis, place, route and verification suite before starting.

Re: Moore’s Law Is About to Get Weird (2015)

#18

Post by GrumpyYoungMan »

TheArcane wrote: post #6

What about Quantum computing?

Quantum computing has nothing to do with what what we would consider "regular" computing. Even if it became practical, at most it would be a specialized accelerator for certain types of computation, like factoring numbers.

A decent explanation can be found here: https://uwaterloo.ca/institute-for-quantum-computing/quantum...

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