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

Apple's M4 has reportedly adopted the ARMv9 architecture

wccftech.com

Post reply on HN
Print view View original

151–160 of 250 posts

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#151

Post by skavi »

hajile wrote: post #141
skavi wrote: post #138

Earlier quoted context omitted.

Does anyone have insight into why arm CPU vendors seem so hesitant about implementing SVE2? ~They seem~ *Apple seems to have no issue with SSVE2 or SME. Edit: Only Apple has implemented SSVE and SME I think.

SVE2 is an extension on top of SVE which some stuff already implements. The issue is more likely to be the politics of moving to ARMv9 than anything else. As to SVE though, I'd guess variable execution time makes the implementation require a bit of work. Normally, multi-cycle tasks have a fixed number. Your scheduler knows that MUL takes N cycles and plans accordingly. SVE seems like it should require N-M cycles depe…

This isn’t a convincing explanation to me. There are plenty of variable latency instructions on existing high performance arm64 cores.

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#152

Post by brigade »

skavi wrote: post #149
brigade wrote: post #146

Earlier quoted context omitted.

What is the measurable benefit to implementing 128b SVE2? Like, ARM has CPUs that implement that, and it's not even disabled on some chips. So there must be benchmarks somewhere showing how worthwhile it is. And implementing 256b SVE has different issues depending on how you do it. 4x256b vector ALUs are more power hungry than generally useful. 2x256b is only beneficial over 4x128b if you're limited by decode width,…

Masked instructions primarily. But apart from that it’s just a more complete ISA vs NEON. More comparable to AVX512/AVX10. > 2x256b is only beneficial over 4x128b if you're limited by decode width This is only true if we ignore more complex instructions and focus on things like adding two vectors.

What is the percentage gain of using masked instructions on any benchmark/task of your choice? It can be negative on weird kernels that do lots of vector cmp since even ARM decided the cost of more than one write port in the predicate register file wasn't worth it, or if the masking adds lots of unnecessary and possibly false dependencies on the destination registers.

> This is only true if we ignore more complex instructions and focus on things like adding two vectors.

ARM implemented a CPU that had 2x256b SVE and 4x128b NEON. Literally the only benchmarks that benefitted from SVE were because they were limited by the 5-wide decode in NEON.

Do you have an actual real-world counterexample?

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#153

Post by LordDragonfang »

JulianWasTaken wrote: post #130
alwillis wrote: post #122

Earlier quoted context omitted.

For those with MacBook Pro FOMO, do not read about the rumored foldable 18.8-inch screen MacBook Pro running on the M5 coming in 2026 [1]. [1]: https://www.macrumors.com/2024/05/23/18-8-inch-foldable-macb...

Without anything but a skim, surely there is no way a MB Pro ships with a virtual keyboard, that is pure torture.

If anything, they'll probably use the "studio" branding (or more likely just have it under the iPad line, since they have desktop chips in them now anyways)

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#154

Post by grecy »

yardie wrote: post #5
capl wrote: post #2

Hmm, I was thinking of buying an M3 Pro 16” this summer, but maybe I should wait then

I'm still on a i7 MBP because everytime I think I'm ready to update the next one is announced.

I just upgraded from a mid 2014 MBP to a used M1 air.

It is much, much faster, silent, and I use it for days without power. Editing 4K video is not just possible, it is a non event.

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#155

Post by dbspin »

solardev wrote: post #136
JulianWasTaken wrote: post #130

Earlier quoted context omitted.

Without anything but a skim, surely there is no way a MB Pro ships with a virtual keyboard, that is pure torture.

Maybe it uses the camera for gesture recognition so you can air-write each letter one at a time? Air-quotes will be fun... air-tabs, not so much. "Space, but BIGGER!"

Obviously Apple's upcoming LLM will be used to infer based on observation of your past behaviour what you would have typed, and type it for you.

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#156

Post by rmccue »

hajile wrote: post #123
ribit wrote: post #29

They have not adopted ARMv9. This is still ARMv8, but with SME.

ARMv9.0 is very similar to ARMv8.5 (9.0 supersets 8.5 with SVE2, TME, TLA, and CCA), so it's not a massive deal. SME implies v8.7 which is basically identical to v9.2 except for those couple extensions previously mentioned. I wonder if there is licensing at play though. Apple may have gotten a really great licensing deal on ARMv8 that they wouldn't be offered for ARMv9.

From what I’ve read previously, Apple has a special licensing deal already as they were part of founding Arm, although I don’t know if there’s any details on exactly how that works.

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#158

Post by dzaima »

hajile wrote: post #141
skavi wrote: post #138

Earlier quoted context omitted.

Does anyone have insight into why arm CPU vendors seem so hesitant about implementing SVE2? ~They seem~ *Apple seems to have no issue with SSVE2 or SME. Edit: Only Apple has implemented SSVE and SME I think.

SVE2 is an extension on top of SVE which some stuff already implements. The issue is more likely to be the politics of moving to ARMv9 than anything else. As to SVE though, I'd guess variable execution time makes the implementation require a bit of work. Normally, multi-cycle tasks have a fixed number. Your scheduler knows that MUL takes N cycles and plans accordingly. SVE seems like it should require N-M cycles depe…

SVE doesn't need variable-execution-time instructions, outside of perhaps masked load/store, but those are already non-constant. Everything else is just traditional instructions (given that, from the perspective of the hardware, it has a fixed vector size), with a blend.

Re: Apple's M4 has reportedly adopted the ARMv9 architecture

#159

Post by fredley »

SllX wrote: post #84
heroprotagonist wrote: post #38

Earlier quoted context omitted.

Every character you type results in some sort of hit to their telemetry server. It will include the actual letter you typed, if you or your org are not configured to be in EU. With their EU configuration option (pulled from server every launch) it will only report the fact that you typed _something_. Now if that's not fun enough, their telemetry also covers mouse movements. Go ahead and watch your CPU as you spin you…

So they’re running a keystroke logger and masquerading it as “telemetry”? That should be outlawed. It’s not a drafts feature, it’s not an online word processor, it’s just a straight up keystroke logger.

It is outlawed, in the EU.
Post reply on HN