6 ms·
What were they doing with the A12Z when they demoed Linux running in a VM at WWDC, then?
by bonyt 6y ago
What were they doing with the A12Z when they demoed Linux running in a VM at WWDC, then?
- saagarjha 6y agoThey must have not been using an A12Z for that.
- fgdfgddfg 6y agoThey already said they were using the mac mini with A12Z for the whole presentation demo
- saagarjha 6y agoWhere?
- lstamour 6y agoThey also mentioned pre-release hardware in the “undisclosed location” — if I recall correctly it was before they did a demo of virtualization. Well, after Googling, I can’t find the exact quote that referenced new hardware in live blogs, but it’s telling that just before they did a demo of virtualization, Maya and so on, they said, “All of the Big Sur features demonstrated earlier were being run on the development platform” according to Anandtech — meaning the earlier Big Sur demo was on the A12Z but the next part would be possibly newer hardware.
- felipemesquita 6y agoThey said a Mac with Apple silicon, not necessarily the developer transition kit. If they were running the demos on the dkt they would probably have shown the device and said so explicitly.
- ridiculous_fish 6y agoParallels clearly has something significant under wraps: https://www.parallels.com/blogs/apple-silicon-wwdc/ https://www.parallels.com/blogs/apple-silicon-wwdc/ My guess: Parallels on Apple Silicon will support virtualizing AArch64 VMs, and also x64 VMs through Rosetta 2. Support for AArch64 alone doesn't seem interesting enough to keep under wraps, and Apple did commit to supporting x64 JITs, so x64 VMs seems like a natural extension.
- 4ad 6y agoWe'll see, but I doubt it. A user-level emulator is a completely different beast performance wise than a full system emulator. With a user-level emulator the kernel, and possibly even the shared libraries are native code, and the code that needs to be emulated is relatively easy to translate from one architecture to another. For a full system emulator not only you need to emulate the kernel also, but all the system-levels instructions have to be emulated as well (unlike user space instruction that can be JITed). Just compare the performance of qemu-system-aarch64 with qemu-aarch64 running on amd64, and you will see a MASSIVE difference in performance. It's very likely rosetta will be more optimised than qemu, but still there is a fundamental problem here. I'm sure qemu-system-x86_64 will run on aarch64 macs, but I doubt Apple/Parallels/VMware will touch this space.
- ridiculous_fish 6y agoFair points, and on reflection you are probably correct. But Apple has a history of weird but successful systems that nobody else tried, like 64 bit user space with a 32 bit kernel, or mixed-endian processes sharing memory. And there's pointed coyness around "Apple Silicon" and Parallels keeping mum. So I want to believe.
- jki275 6y agoI need to believe because it makes a massive difference for me as an embedded developer. I can't use Macs anymore if I can't run multiple x64/x86 Linux VMs on them.
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- jagged-chisel 6y agoOne can certainly write software that virtualizes another machine. Sure, performance might not be great. Sure, it's better if you have an implementation in silicon. But that doesn't prevent making a demo of a software VM running another kernel. What am I missing?
- saagarjha 6y agoI would consider that a fraudulent demo, since it is selling something different from what it is showing.
- scoopertrooper 6y agoNo? There was nothing in the context of that video to suggest it was running on an A12Z. They were showing you the features that will be available on the chip they're going to bring to market sometime this year. This chip must already exist in a near-production form in order to meet that deadline.
- saagarjha 6y agoI’m not saying they did, I’m pretty sure they were running it on an undisclosed chip. What would be fraudulent would be emulating it on the A12Z and claiming they were virtualizing.
- jki275 6y agoApple isn't selling anything at the moment. It was only an announcement, and it remains to be seen if what they deliver matches what they announced.
- waon 6y agoNot sure what you mean by "software VMs," but if you mean CPU emulators, they're fundamentally different from VMs. Emulation is not "virtualization."
- soganess 6y ago
- lsllc 6y agoIt appeared to be Ubuntu for ARM64. If it wasn't virtualized, could it have been running under QEMU? Or maybe some sort of WSL type shim into the Darwin kernel?
- intpx 6y agopardon my ignorance, but how is QEMU not virtualization? There have been MacOS builds of KVM/QEMU for a couple of years now and I distinctly remember seeing that it had either been added or was being added to the base OS (google-fu is failing me because of so many results about the reverse-- running MacOS under KVM/QEMU).
- jki275 6y agoQEMU is an emulator, not virtualization. It allows the user to run an OS designed for one type of CPU on a host system of a different type. i.e running Raspbian (ARM Linux) through QEMU on an X64 Linux Host running on an X64 machine. Virtualization, by contrast, allows the user to run a guest OS designed for the same architecture as the physical hardware. i.e running x64 Linux guest on an X64 host that runs Windows as a host OS.
- dekhn 6y agoBut to add to the complexity, many virtualization systems use QEMU as a support library to achieve stuff.
- jki275 6y agoI'm not nearly smart enough on that stuff. I fear I will need to get deeply into it in order to setup tooling that will run on the new Macs for embedded development.
- waon 6y agoThat's hardly the point. Many virtualization systems do indeed use QEMU for device emulation, but they don't use it to emulate the entire CPU functionality itself. A key point about virtualization is that most code run native while privileged instructions are trapped and handled by the hypervisor, allowing multiple guest OSes to coexist. This gives guest OSes the illusion that it's in sole control of the hardware.
- intpx 6y agoI'd argue that very little is actually known about the A12Z hardware implementation details because there are not many out there and they are largely in the hands of folks trying to build their commercial software as fast as they can. I'd wager the MacOS 11 build for these developer platforms is largely focused on just making sure Xcode runs and not extensibility in the system software
- saagarjha 6y ago> I'd argue that very little is actually known about the A12Z hardware implementation details It shipped on a couple million iPads, we know a decent amount about it already.