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Confused-User

macrumors 6502a
Oct 14, 2014
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925
You may be confusing that with requirements for nested virtualization. That does indeed require an M3 (not M4, no macs have that yet :-( ), even though the hardware feature is in M2. Most likely, it's slightly broken in M2.
 

crazy dave

macrumors 65816
Sep 9, 2010
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There is a rumor that Game Porting Toolkit 2 will only help games that use the AVX2 instruction set on M4-based computers. Is there any truth to that?

No, Rosetta 2 AVX2 works on every M* Mac.
Rosetta 2 did not use to support AVX 2. [EDIT 3: Ah, I think I misunderstood your post to mean it always had supported it - i.e. prior to GPTK2. It does support it now and it does seem to be across every M* Mac.


Rosetta can translate most Intel-based apps, including apps that contain just-in-time (JIT) compilers. However, Rosetta doesn’t translate the following executables:

  • Kernel extensions
  • Virtual Machine apps that virtualize x86_64 computer platforms
Rosetta translates all x86_64 instructions, but it doesn’t support the execution of some newer instruction sets and processor features, such as AVX, AVX2, and AVX512 vector instructions.

The above webpage as of writing for instance has not been updated to include AVX/2 support. Sorry for the confusion. ]

AVX 2 is new to GPTK 2.0 and presumably works through Rosetta 2 and indeed it doesn't mention a requirement for M4. It should be easily testable by developers with Sonoma beta.

https://developer.apple.com/games/game-porting-toolkit/

EDIT: While the above webpage talks about bringing your game to both Mac and iOS/iPadOS I don't think iPadOS actually supports running Rosetta 2. So unless that's changed, it would be extra strange to have an M4 requirement as no one would be able to use it at the moment. The WWDC24 developer video shows the emulation environment running on a Mac with no mention of iPad:


So no I think this rumor about M4 only AVX2 support is wrong. Again, should be easily testable. @Xiao_Xi where did this rumor come from?

EDIT2: Ah it seems the beta AVX2 support is not fully working yet however CPUID claims it will work on M1s so it should be across the entire lineup once it is fully enabled.



You may be confusing that with requirements for nested virtualization. That does indeed require an M3 (not M4, no macs have that yet :-( ), even though the hardware feature is in M2. Most likely, it's slightly broken in M2.

I think Hector got nested virtualization working in the M2 on Linux. This may be more like how Apple released clamshell support for more monitors for the M3 Air but the M2 could've done so as well (my fuzzy memory is that I think they changed the display controller since the M1 so it may not be able to).

EDIT: they [Asahi Linux team] don't quite have nested virtualization out yet [for Linux], but it was indeed developed and tested on the M2:

 
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MrGunny94

macrumors 65816
Dec 3, 2016
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I wonder what is the situation now with display controllers compared to M3?

I'd really like to see native support for 3 displays on base M4. I'd even buy the base MBP with that.
Doubt it due to die space, being able to have dual displays natively on the Air is already a good step in the right direction.

But I don’t see them pushing this any forward as the Pro/Max can do that.

Only reason they changed on the Air was due to the enterprise pressure
 
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Xiao_Xi

macrumors 68000
Oct 27, 2021
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@Xiao_Xi where did this rumor come from?

EDIT: they don't quite have nested virtualization out yet, but it was indeed developed and tested on the M2:
It appears that Apple has enabled nested virtualization for M3 and later.
Nested virtualization is available for Mac with the M3 chip, and later.
 
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crazy dave

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Sep 9, 2010
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As usual Vadim appears to be wrong about technical matters. Not sure where he got that from. Also ARMv9 AVX2 support what's he on about? Is he confusing AVX2 with SVE2? Either way it doesn't matter since the M4 doesn't have SVE2 either. Its vector processors are still NEONs. Maybe he thinks SSVE2/SME2 is how Apple is emulating AVX2? That's probably giving him too much credit and while I don't know for sure, I also kinda doubt that's how Apple is emulating AVX2, but maybe? I would've thought it was being done through the NEONs even though they are 128b. But regardless, AVX2 support seems to be functional for the M1, M2, and M3 (which even if it is the matrix accelerator being used to emulated AVX2, again seems unlikely to me, the M1-3 have the matrix accelerator as well - they're just using Apple's private extensions rather than ARM's official matrix extensions).

Bottom line: there's no way to make sense of what he's saying here. Which, as I opened with, is pretty much expected for MaxTech on anything technical.

It appears that Apple has enabled nested virtualization for M3 and later.


Sorry my "they" was unclear. I was referring to the Asahi Linux team, not Apple. Asahi Linux don't quite have nested virtualization upstreamed to Linux yet but when they [Asahi] do, it'll be for the M2. So it is in theory possible for Apple to support nested virtualization on the M2 too.

I've re-re-re-edited my previous post for clarity. :)
 
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leman

macrumors Core
Oct 14, 2008
19,494
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As usual Vadim appears to be wrong about technical matters.

Now that is just frustrating. Vadim has a large audience, why post obviously nonsensical things?

@vadimyuryev Please, correct this. You are doing the community a disservice. AVX2 emulation is present on every ARM Mac, Armv9 does not have any "AVX2 support". What's more, M4 does not have SVE (scalable vector extension), which is expected to be included with a typical ARMv9 implementation.
 

crazy dave

macrumors 65816
Sep 9, 2010
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Now that is just frustrating. Vadim has a large audience, why post obviously nonsensical things?

@vadimyuryev Please, correct this. You are doing the community a disservice. AVX2 emulation is present on every ARM Mac, Armv9 does not have any "AVX2 support". What's more, M4 does not have SVE (scalable vector extension), which is expected to be included with a typical ARMv9 implementation.
I forgot he had an account here. Hopefully he sees this and corrects the record.

A more interesting conversation: is there any info yet on how Apple is doing AVX2 support? Presumably through the NEONs, right? Its performance should be interesting to test.
 

MrGunny94

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Dec 3, 2016
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About the AVX2, I believe this is a step in the right direction , right now we just need to wait and see how developers adapt their GPKT2 pipelines as well in future releases.

But one thing is clear, there’s more and more games available on the Mac and publishers like Ubisoft are releasing some of their games on day 1

As usual Vadim appears to be wrong about technical matters. Not sure where he got that from. Also ARMv9 AVX2 support what's he on about? Is he confusing AVX2 with SVE2? Either way it doesn't matter since the M4 doesn't have SVE2 either. Its vector processors are still NEONs. Maybe he thinks SSVE2/SME2 is how Apple is emulating AVX2? That's probably giving him too much credit and while I don't know for sure, I also kinda doubt that's how Apple is emulating AVX2, but maybe? I would've thought it was being done through the NEONs even though they are 128b. But regardless, AVX2 support seems to be functional for the M1, M2, and M3 (which even if it is the matrix accelerator being used to emulated AVX2, again seems unlikely to me, the M1-3 have the matrix accelerator as well - they're just using Apple's private extensions rather than ARM's official matrix extensions).

Bottom line: there's no way to make sense of what he's saying here. Which, as I opened with, is pretty much expected for MaxTech on anything technical.



Sorry my "they" was unclear. I was referring to the Asahi Linux team, not Apple. Asahi Linux don't quite have nested virtualization upstreamed to Linux yet but when they [Asahi] do, it'll be for the M2. So it is in theory possible for Apple to support nested virtualization on the M2 too.

I've re-re-re-edited my previous post for clarity. :)
I think the guys at MaxTech got very confused over the latest couple of news. I love their channel but there-s some things that for sure need improvement.

Most likely it’s related to have the videos posted on time and there isn’t a lot of info until after the panels and Apple documentation is fully updated during WWDC

Regardless their videos are really good for the general audience who wants to learn more, their real world tests are good. The only complaint I have is that they should have more work general Microsoft workloads opened.
 

crazy dave

macrumors 65816
Sep 9, 2010
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I think the guys at MaxTech got very confused over the latest couple of news. I love their channel but there-s some things that for sure need improvement.

Most likely it’s related to have the videos posted on time and there isn’t a lot of info until after the panels and Apple documentation is fully updated during WWDC

Regardless their videos are really good for the general audience who wants to learn more, their real world tests are good. The only complaint I have is that they should have more work general Microsoft workloads opened.
This isn't a recent phenomenon with them. It's ongoing. Unfortunately for a general audience whenever they try to explain something even just a little bit technical they are typically very muddled and often flat out wrong like the above. This is far from the first time that they've essentially put out misinformation. I don't think it's malicious, but while they can run the tests and present them, they simply don't have the necessary expertise to expand on technical details and interpret the results beyond the surface level. And worse still they don't seem to pay attention to the people who do have the technical background to tell them differently. Which is why @thenewperson is rather cynical that a correction will be issued though in this case given that it is so glaringly obviously, provably wrong, that I hope it will be.

Look I'd love for them to become the channel they clearly want to be: a popular YouTuber with lots of Mac content (I know they do other things too) able to break down technical content for a general audience, but at this point even I have to admit that MaxTech simply doesn't have the right people for the last part. At first, I was optimistic that they'd learn, connect with engineers and technical experts, and, overtime, do better, but honestly the above shows that they're just getting worse.

EDIT: looks like his Twitter post has been deleted. I don't have Twitter. Did he issue any kind of correction? or just delete?
 
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name99

macrumors 68020
Jun 21, 2004
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Rosetta 2 did not use to support AVX 2. [EDIT 3: Ah, I think I misunderstood your post to mean it always had supported it - i.e. prior to GPTK2. It does support it now and it does seem to be across every M* Mac.




The above webpage as of writing for instance has not been updated to include AVX/2 support. Sorry for the confusion. ]

AVX 2 is new to GPTK 2.0 and presumably works through Rosetta 2 and indeed it doesn't mention a requirement for M4. It should be easily testable by developers with Sonoma beta.

https://developer.apple.com/games/game-porting-toolkit/

EDIT: While the above webpage talks about bringing your game to both Mac and iOS/iPadOS I don't think iPadOS actually supports running Rosetta 2. So unless that's changed, it would be extra strange to have an M4 requirement as no one would be able to use it at the moment. The WWDC24 developer video shows the emulation environment running on a Mac with no mention of iPad:


So no I think this rumor about M4 only AVX2 support is wrong. Again, should be easily testable. @Xiao_Xi where did this rumor come from?

EDIT2: Ah it seems the beta AVX2 support is not fully working yet however CPUID claims it will work on M1s so it should be across the entire lineup once it is fully enabled.





I think Hector got nested virtualization working in the M2 on Linux. This may be more like how Apple released clamshell support for more monitors for the M3 Air but the M2 could've done so as well (my fuzzy memory is that I think they changed the display controller since the M1 so it may not be able to).

EDIT: they [Asahi Linux team] don't quite have nested virtualization out yet [for Linux], but it was indeed developed and tested on the M2:


Can you explain to me, like I'm a 6 yr old, why nested virtualization is interesting to me, to the average person, or even to the non-average person?
 

name99

macrumors 68020
Jun 21, 2004
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As usual Vadim appears to be wrong about technical matters. Not sure where he got that from. Also ARMv9 AVX2 support what's he on about? Is he confusing AVX2 with SVE2? Either way it doesn't matter since the M4 doesn't have SVE2 either. Its vector processors are still NEONs.
And will remain NEON.
SVE/2 AUGMENTS NEON, it doesn't replace it. Like AVX512 augments AVX2, it doesn't replace it.
 
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name99

macrumors 68020
Jun 21, 2004
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Ratchet & Clank: Rift Apart is running on an M1 chip here 🤷🏼‍♂️
Again, why is this interesting?
Is the point that it's a game based on AVX2 rather than on a GPU?
Not being snarky, trying to understand the technical implications.
 

crazy dave

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Sep 9, 2010
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And will remain NEON.
SVE/2 AUGMENTS NEON, it doesn't replace it. Like AVX512 augments AVX2, it doesn't replace it.
Sure, I was just pointing out that the vector units don't support SVE2 like Vadim seemed to be suggesting and certainly has claimed in the past. I don't know if you saw the Twitter post that spurred this convo, but it was incredibly muddled talking about how ARM v9 was required for GPTK 2's AVX2 support.

Can you explain to me, like I'm a 6 yr old, why nested virtualization is interesting to me, to the average person, or even to the non-average person?

Me? Personally, no, as a virtualization feature I would prefer PCIe passthrough. I'm probably niche so I'm not actually expecting Apple to support my use case anytime soon. But Apple saw fit to add hardware acceleration for nested virtualization and now support it in software. So enough users must want it that Apple did all that. My point was that the M2 had the hardware support, but Apple is, so far, only adding it to the M3. How many people that makes a difference to is unknown to me.

This again was based on the misunderstanding from Vadim that GPTK 2 AXV2 support would be limited to the M4, which it will not.

Again, why is this interesting?
Is the point that it's a game based on AVX2 rather than on a GPU?
Not being snarky, trying to understand the technical implications.
It runs on the GPU but it also required AVX2 emulation to work. This is apparently true for a decent number of recent games. A number of developers/porters have appeared over the moon ecstatic about AVX2 emulation support (more so than even ray tracing emulation support at least from what I've seen - one suspects because a game doesn't work at all without AVX2 support but the other just means the ray tracing can't be emulated). So obviously a big deal for them. And again, the TechTuber in question had said this emulation wouldn't work on the M1 when it ... does.
 
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Xiao_Xi

macrumors 68000
Oct 27, 2021
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Can you explain to me, like I'm a 6 yr old, why nested virtualization is interesting to me, to the average person, or even to the non-average person?
I have read two cases, but I don't know if they are popular. The first, running Desktop Docker in a VM instead of macOS and the second, running WSL in a Windows VM.
 

livmatus

macrumors regular
Feb 1, 2020
129
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But I don’t see them pushing this any forward as the Pro/Max can do that.

Only reason they changed on the Air was due to the enterprise pressure

well, I get it that Apple now pushes customers to buy a Pro machine with at least Pro M chip ... to get a functionality that was available even on base Macbook Air since 2012 to the last Intel model in 2020

so not only they downgraded the Air ... but also a Pro with non-Pro chip ... it's a mess
 

crazy dave

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Sep 9, 2010
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well, I get it that Apple now pushes customers to buy a Pro machine with at least Pro M chip ... to get a functionality that was available even on base Macbook Air since 2012 to the last Intel model in 2020

so not only they downgraded the Air ... but also a Pro with non-Pro chip ... it's a mess
The issue is that Apple display controllers are huge with massive SRAM caches for storing display state. The likely reason people give for why Apple does this is power savings, but there may be other uses for it as well. The downside is that the display controllers take up 25% of the base M-SOC die area. Increasing the number of them would balloon the cost of the die unreasonably. Now there is a discussion to be had (and people have had it on here) about why the display controllers have to be so big with questions like if it is just for power savings (and we don't know that) why can't they use more, smaller controllers that might burn somewhat more power but ultimately if you are connected to multiple displays you are almost certainly plugged in anyway? But I'm not fully equipped to answer that question and from what I remember of the discussion I don't think anyone has really any hard info, just speculation.

Even on the Pro and Max which have multiple external display controllers, they are all the same big size and only take up less die space proportionally due to how big the rest of the units, especially GPU, get on those SOCs. So Apple likely has a reason to spend that die area on large controllers even for those multi-external display controller chips, it's just not totally clear what that is beyond power savings which doesn't seem to quite fit to me or at least doesn't tell the whole story.

If I was to participate in unfounded wild speculation I might suggest that Apple's fast resolution switching and other display techniques is based on having such large caches but, again, I don't know that. And "knowing that" would require detailed comparisons between AS Macs and Intel Macs.
 
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Pressure

macrumors 603
May 30, 2006
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Again, why is this interesting?
Is the point that it's a game based on AVX2 rather than on a GPU?
Not being snarky, trying to understand the technical implications.
That person on X and YouTube claimed that AVX2 was only going to work on M4 but here is a game that requires AVX2 that runs on M1.
 
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NT1440

macrumors Pentium
May 18, 2008
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This isn't a recent phenomenon with them. It's ongoing. Unfortunately for a general audience whenever they try to explain something even just a little bit technical they are typically very muddled and often flat out wrong like the above. This is far from the first time that they've essentially put out misinformation. I don't think it's malicious, but while they can run the tests and present them, they simply don't have the necessary expertise to expand on technical details and interpret the results beyond the surface level. And worse still they don't seem to pay attention to the people who do have the technical background to tell them differently. Which is why @thenewperson is rather cynical that a correction will be issued though in this case given that it is so glaringly obviously, provably wrong, that I hope it will be.

Look I'd love for them to become the channel they clearly want to be: a popular YouTuber with lots of Mac content (I know they do other things too) able to break down technical content for a general audience, but at this point even I have to admit that MaxTech simply doesn't have the right people for the last part. At first, I was optimistic that they'd learn, connect with engineers and technical experts, and, overtime, do better, but honestly the above shows that they're just getting worse.

EDIT: looks like his Twitter post has been deleted. I don't have Twitter. Did he issue any kind of correction? or just delete?
You see this everywhere in life. A person is a subject matter in X, and therefore everyone in the room implicitly thinks that person is informed in Y. Except for the subject matter expert on Y who is shocked that anyone is listening to this patently wrong idiot.
 

crazy dave

macrumors 65816
Sep 9, 2010
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You see this everywhere in life. A person is a subject matter in X, and therefore everyone in the room implicitly thinks that person is informed in Y. Except for the subject matter expert on Y who is shocked that anyone is listening to this patently wrong idiot.
Thing is I feel this way and I can't even claim to be a subject matter expert myself, not in this topic anyway. And on the flip side, knowing enough to be dangerous, I'd hate to think how many wrong things I'd say with complete confidence if I were to try to run a TechTube channel. At least being a small voice participating on forums my wrongness is fairly well contained to a small audience and, since it is a discussion, can be more easily corrected by someone who knows of what they speak.
 

NT1440

macrumors Pentium
May 18, 2008
15,088
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Thing is I feel this way and I can't even claim to be a subject matter expert myself, not in this topic anyway. And on the flip side, but knowing enough to be dangerous, I'd hate to think how many wrong things I'd say with complete confidence if I were to try to run a TechTube channel. At least being a small voice participating on forums my wrongness is fairly well contained to a small audience.
I contribute where I can. My job has me involved in tons of different fields of technology and troubleshooting. I’m the first to ask for clarification here on things I’m out of my depth on.

That said, the smartest people are always the ones that both A) Understand how little they know given the depths of knowledge on a given topic ,and B) Can determine how much another person actually understands about a topic by actually listening to them.

This MaxTech channel has always given me negative feelings in regards to B). As soon as a topic isn’t directly related to gaming specs they seem to have an above average (but nowhere near adequate to *explain*) understanding of computers. Lots of purely wrong extrapolations and throwaway comments that’s underline they don’t get how X or Y works under the hood.
 

crazy dave

macrumors 65816
Sep 9, 2010
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Does Rosetta support AVX2 only in macOS Sequoia?
https://www.reddit.com/r/macgaming/comments/1dd8jvs
Yes (so far). Rosetta 2 support for AVX2 is part of GPTK 2.0 announced as a Sequoia upgrade and is likewise part of the Sequoia Beta. Apple might choose to expand official support to older OSes. They may not. For those unconcerned with official support, this technique looks like it will work for those who don't want to upgrade from Sonoma and want Rosetta-AVX2, but once Sequoia leaves Beta, I don't think that'll be a major hangup.

The performance benchmarks are interesting. Difficult to know how expected that is, emulating 256b AVX2 with presumably 128b NEON, or if we can expect further improvements. Also not clear, beyond the emulation, how efficiently this particular benchmark is testing the two sets of vector units but I suppose the point is that unless you're the developer you aren't in a position to optimize the code for emulation in NEON. Finally of course as one person in that thread points out, if the AVX2 emulation is "good enough" to not be a (severe) bottleneck for these games, absolute emulation performance is less important.
 
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MrGunny94

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Dec 3, 2016
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well, I get it that Apple now pushes customers to buy a Pro machine with at least Pro M chip ... to get a functionality that was available even on base Macbook Air since 2012 to the last Intel model in 2020

so not only they downgraded the Air ... but also a Pro with non-Pro chip ... it's a mess
Yep, that's the story for the last 3 consumer grade releases outside of the Pro.

And the thing is, when you start adding storage and memory on the Air model (Especially IN EUROPE) there's no point in getting any of the Air or desktop versions and just instead opt for the Pro versions.
 
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