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Ask HN: Can competitors catch up to Apple Silicon?

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Re: Ask HN: Can competitors catch up to Apple Silicon?

#221

Post by throwaway4good »

jurmous wrote: post #134
throwaway4good wrote: post #80

Earlier quoted context omitted.

China has their infamous five year plans and for 2025 they have a goal of suppying 70% of their own semiconductor demand. So it is pretty much given that we will see high-end Chinese CPUs by then.

Good luck with that if you cannot get the latest chipmaking machines from ASML. There is basically no competitor to ASML for latest gen chipmaking machines. https://www.reuters.com/technology/asml-still-has-no-licence...

Yes. This is the heart of the tech war.

On the Chinese side there is nothing short of a Manhattan project going on to create a semi-conductor industry that is outside US sanction power.

It will be absolutely fascinating to see the result of it.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#222

Post by throwaway4good »

layer8 wrote: post #175
cowtools wrote: post #169

Earlier quoted context omitted.

I would imagine that any implementation of x86 would have to bear the weight of reverse-compatibility. With reverse comparability, the bad design decisions just compound, for example complicated stuff like memory synchronization https://youtu.be/KeLBd2EJLOU?t=2956

Exactly. I wish it wasn’t the case, but x86 compatibility will always come at a cost, in particular due to memory semantics, but also I believe due to its complex ISA requiring more silicon.

It would have been a critical factor if this was circuits with a few thousands transistors.

Here is an article on the subject; I am sure you can find others:

https://chipsandcheese.com/2021/07/13/arm-or-x86-isa-doesnt-...

ARM or x86? ISA Doesn’t Matter

Re: Ask HN: Can competitors catch up to Apple Silicon?

#223

Post by hajile »

modeless wrote: post #114

You're looking in the wrong place. The magic comes from TSMC, not Apple. Apple's major innovation is in using their unrivaled bank account to pay TSMC for exclusivity on their newest fabrication technology. As competitors gain access to that TSMC technology they will match or beat Apple's performance. And if Intel succeeds in reclaiming the fabrication technology lead from TSMC (we'll see) then Intel will beat Apple'…

A13 and Zen 2/3 were all on TSMC N7, but A13 still crushes in performance per watt by a HUGE margin.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#224

Post by fooker »

Asooka wrote: post #203
rob74 wrote: post #23

Earlier quoted context omitted.

Both Intel and AMD have the major disadvantage of having (or, let's say, wanting) to maintain x86 backward compatibility - which means not only staying compatible with the almost 45 year old CISC instruction set of the Intel 8086, but also with the whole line of CPUs that came after it. All this ballast makes it harder for them to build an energy-efficient CPU. By contrast, Apple was able to just create a new CPU bas…

But you can run x86 software on the M1 at almost native speed through a software translator. Isn't that proof enough that the instruction set itself isn't what's holding back the hardware?

Most of the translation is done ahead of time, not something you pay for while running.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#226

Post by wmf »

tdsanchez wrote: post #194

Most of the performance advantage of Apple silicon is that it puts CPU, GPU and all memory (that is typically VRAM and DRAM in traditional architectures) millimeters from primary DRAM. When competing purveyors start do this with their own clever packaging, they will start to approach Apple’s mips/watt. Emulation on M1 is outstanding. The spatial locality of main memory nullifies emulation penalty. Apple has come clos…

Nope. There's little or no advantage to 2 mm vs. 20 mm.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#227

Post by throw34 »

modeless wrote: post #211
throw34 wrote: post #208

Earlier quoted context omitted.

That’s an interesting take given this thread because Apple has explicitly stated they don’t prioritize performance, they prioritize performance per watt, which is not the same thing. And that also shows there’s a whole design space here and just focusing on one dimension, process node, is overly simplistic.

Top end performance is power limited, so optimizing for performance per watt is almost the same thing as optimizing for performance.

I’m not sure what point you’re arguing anymore.

I’m arguing against this statement. I don’t think it’s true.

“ You're looking in the wrong place. The magic comes from TSMC, not Apple.”

My point is a good process is necessary but not sufficient to make a part competitive with Apple on performance per watt. There’s a lot of “magic” to go around.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#228

Post by kersplody »

chrisseaton wrote: post #36
norman784 wrote: post #24

I think if x86 get rid of their legacy instructions, they could reduce their core size, and a few side effects will be performance per watt gains and maybe also performance (smaller cores), and if you need the legacy instructions you could just emulate, most consumer PCs don't need those. That's the biggest difference with x86 and ARM, ARM got a lot of breaking changes with their versions, while x86 don't (I'm not su…

> I think if x86 get rid of their legacy instructions, they could reduce their core size Aren't those legacy instructions already emulated in microcode? I don't think they take up much physical footprint.

Modern x86 processors use about 10% of their power budget for instruction decode (translate variable-length x86 machine code into one or more fixed-length microcode instructions and remap registers). The primary modern benefit of this setup is that the decode logic can optimize code at the cost of power.

If x86 could get rid of the x86 instruction set and compile directly to something similar to uOPs, then some power reduction use and core area reduction could be achieved, but tooling cost would be immense.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#229

Post by kersplody »

layer8 wrote: post #177
norman784 wrote: post #24

I think if x86 get rid of their legacy instructions, they could reduce their core size, and a few side effects will be performance per watt gains and maybe also performance (smaller cores), and if you need the legacy instructions you could just emulate, most consumer PCs don't need those. That's the biggest difference with x86 and ARM, ARM got a lot of breaking changes with their versions, while x86 don't (I'm not su…

X86 will always be slower because it has stricter memory ordering semantics.

Not really an issue under most usage scenarios. x86 suffers mostly from the cost and complexity of the decode unit. Once decoded instructions are cached, the performance penalty mostly disappears.

Re: Ask HN: Can competitors catch up to Apple Silicon?

#230

Post by hajile »

pclmulqdq wrote: post #210
gary_0 wrote: post #158

Earlier quoted context omitted.

And those bytes matter when most Intel CPU cores have only a few dozen KB of L1I cache. Interestingly, the M1 and M2 performance cores have a whopping 192KB of L1 instruction cache.

ARM instructions aren't as compact as their x86 counterparts, so they need a big cache to get similar performance on cache-bound applications.

ARM aarch64 instructions are around 12-15% bigger overall, but cache sizes are much larger than that. Most likely that is so they can power the massive reorder buffer and deal with having code for tons of branches handy.
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