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Ask HN: Is Moore's Law over, or not?

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Re: Ask HN: Is Moore's Law over, or not?

#71

Post by jdsully »

dyingkneepad wrote: post #65
kpw94 wrote: post #27

Earlier today on HN there was a submission about great CPU stagnation. In the blog post was an interesting link: https://raw.githubusercontent.com/karlrupp/microprocessor-tr... This graph to me show that while yes technically Moore's law of doubling transistor per "thing Intel or AMD sells you" is still holding, it has ended for single threaded workloads. Moore's law is only holding due to core count increase. For ev…

My most CPU-intensive usage is compilation and "make -j8" is doing a pretty good job at scaling things to fully utilize my CPU. It's not about one program using all your resources.

Linking is still super slow, especially if you use link time code generation.

Re: Ask HN: Is Moore's Law over, or not?

#72

Post by eat »

hef19898 wrote: post #32
andrewstuart wrote: post #29

Earlier quoted context omitted.

Nvidia is trying to reset expectations of consumers. Jensen aims to charge more for more GPU computing power into the future. This is because Nvidia has close to monopoly power this is able to break Moores Law single handedly.

Hell, they are able to sell graphic cards, well not nVidia themselves but still, in excess of 2k bucks. They'd be stupid not to try to keep prices that high, now the market seemlingy accept them.

I don't understand the part about the market accepting the price, or rather, I find it hard to believe that it's sustainable. I've played PC games my whole life and used to enjoy building and re-building my gaming PC every so often. Paying 2k for a single piece of hardware just doesn't seem like the right choice anymore. Makes more sense to buy a console (or two) these days.

Re: Ask HN: Is Moore's Law over, or not?

#73

Post by eklitzke »

jdsully wrote: post #71
dyingkneepad wrote: post #65

Earlier quoted context omitted.

My most CPU-intensive usage is compilation and "make -j8" is doing a pretty good job at scaling things to fully utilize my CPU. It's not about one program using all your resources.

Linking is still super slow, especially if you use link time code generation.

LTO basically just calls back into the compiler and is multi-threaded on lld and mold at least, and probably anything else that supports LTO. And make sure you're using ThinLTO, it's still expensive but much faster than full LTO.

Re: Ask HN: Is Moore's Law over, or not?

#74

Post by silisili »

ipsum2 wrote: post #31
silisili wrote: post #25

Earlier quoted context omitted.

Yeah, after listening to Keller speak about it on Lex's podcast, I'm convinced he probably knows more than about anybody. Another vote for not dead.

Why do you feel the need to appeal to authority here? Moore's law states that the number of transistors on a chip doubles every two years. Looking at the data[0] confirms, yes, Moore's law is still alive. [0]: https://upload.wikimedia.org/wikipedia/commons/0/00/Moore%27...

That's a nice graphic, thanks. I guess I was talking about the future, more than the right now. During the first Friedman interview, he went into detail about just how small things could go, and why we're a far way away from hitting that limit.

Re: Ask HN: Is Moore's Law over, or not?

#75

Post by btilly »

ascar wrote: post #36
btilly wrote: post #4

Nvidia thinks that Moore's Law is dead. https://arstechnica.com/gaming/2022/09/do-expensive-nvidia-g... Intel, by contrast, says that Moore's Law is still alive. But Intel is technologically behind, and it is easier to improve when there is someone to learn from, so maybe there is a wall that they haven't yet hit. Regardless, it is a very different law than when I was young, when code just magically got faster each y…

> but the timing for an individual single-threaded computation hasn't really improved in the last 15 years The clock speeds haven't really gone up anymore, but computations still got considerably faster. From an i7 2700k (2011) to an i7 13700k single core benchmark scores went up 131% https://cpu.userbenchmark.com/Compare/Intel-Core-i7-2700K-vs...

First, that's the kind of change we used to get in 2 years. Having it happen over a decade is barely noticeable compared to where we used to be.

Second, over that time period we've had a lot of changes in tooling. Some make code faster. Most make code slower. (Examples include the spread of containerization, and adoption of slow languages like Python.) The result is that programs to do equivalent things might wind up actually faster or slower, no matter what a CPU benchmark shows.

Re: Ask HN: Is Moore's Law over, or not?

#76

Post by ascar »

btilly wrote: post #64
ascar wrote: post #56

Earlier quoted context omitted.

> Unlike in gaming in the data center initial cost + performance per watt are the only thing that really matter That's not true from a hardware perspective either. You can't just plug in 4 worse cards in the same rack. The savings on the graphics cards become less significant if you need to double/quadruple all other hardware to increase the number of racks. A 1U blade can easily cost $10000 without a graphics card.

You can plug in multiple GPUs on a computer. AWS has fleets with 4 and 8, see https://docs.aws.amazon.com/dlami/latest/devguide/gpu.html for pricing. For anything datacenter related, customers are very sensitive to price per performance. And datacenters are happy to oblige.

You're missing the point GP made though. He wants to replace one good card with 4 worse ones. It's not like that rack has 3 or 7 additional slots just unused. They're also already taken by the setup. And in the link you provided 5 out of 6 offerings are still Nvidia GPUs.

Of course data centers are happy to oblige to customer demands, but initial cost per GPU and performance per watt are certainly not the only relevant factors.

Re: Ask HN: Is Moore's Law over, or not?

#77

Post by satvikpendem »

jdsully wrote: post #71
dyingkneepad wrote: post #65

Earlier quoted context omitted.

My most CPU-intensive usage is compilation and "make -j8" is doing a pretty good job at scaling things to fully utilize my CPU. It's not about one program using all your resources.

Linking is still super slow, especially if you use link time code generation.

Have you tried the mold linker? I've been using it and it works pretty well, quite fast.

https://github.com/rui314/mold

Re: Ask HN: Is Moore's Law over, or not?

#79

Post by bjourne »

The original Moore's law was about transistors per chip AT CONSTANT COST. That has ceased to be true as design and fabrication costs are increasing exponentially. However, the number of transistors per chip (regardless of cost) has still tracked Moore's law.

What is definitely over is Dennard scaling. As transistors got smaller it used to be possible to reduce the current used to drive them. That in turn made it possible to increase the clock frequency without frying the chip. Heat dissipation is proportional to the frequency and drive current. It's not possible anymore because you have leakage current and other parasitics (electrical noise essentially) that does not scale with transistor size. In the past you could take a 486 dx, overclock it from 25 to 50MHz and it would "magically" get about twice as fast. That is not possible anymore and chips are unlikely to ever run much faster than 5GHz.

However, Moore's law still provides performance because you can fit more cores, larger caches, specialized circuits, SIMD units, etc, on the same chip.

Re: Ask HN: Is Moore's Law over, or not?

#80

Post by TanjB »

When Moore wrote in 1965, commercial use of MOS was 10 years in the future and Dennard scaling would not become widely understood and stirring interest in CMOS until 15 years in the future. So, he was actually observing an era much like now, with multiple chiplets inside the can and all sorts of random improvements that had an emergent trend. The Dennard era, which gave Moore its main impulse, was about 20 years long. Maybe 25 years if you include controlling tunnel leakage by introducing Hf-based dielectrics, and FinFETs since they sort of crinkle the surface of the chip to give you double the area, and otherwise obey classic Dennard laws of constant power per unit area.

But even during the Dennard era there were a bunch of big random innovations needed to keep things going. CMP allowing the number of metal routing layers to balloon, keeping distances under control. Damascene metals allowing much finer metals carrying heavier currents. Strained channels for higher frequency and better balance between P and N. Work-function-biased fully depleted transistors to avoid the stochastic problems with doping small channels. Etc.

So what really happened is not that Moore ended. We still have a wealth of random improvements (where "wealth" is the driving force) which contribute to an emergent Moore improvement. But the large change is Dennard ended, which gave us scaling at constant power. Although some of the random improvements do improve energy efficiency per unit of computation, they are not overall holding the line on power per cm2. At the end of the classic Dennard we were around 25W /cm2 but now we commonly have 50W in server chips, and there are schemes in the works to use liquid cooling up to hundreds of W / cm2.

Well, ok. But does that kill Moore? Not if it keeps getting cheaper per unit function. And by that I do not mean per transistor. But as long at that SOC in your phone keeps running faster radio, drawing better graphics, understanding your voice, generating 3D audio, etc., and is affordable by hundreds of millions of consumers, Moore remains undead.

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