I'd bet for the null hypothesis: the memory behaviour changes would hold if the core count was kept constant and only the VM's memory size was adjusted.

As a general rule, also the amount of physical memory installed in a computer should be proportional with the number of hardware threads provided by its CPU.

Besides the fact that the operating system may allocate some memory for each thread, when you launch a multi-threaded application that is able to use all available threads, for instance the compilation of a big software project, it frequently will allocate some working memory in an amount proportional with the amount of working threads.

I have encountered many multi-threaded applications that need up to 2 GB per thread to work well.

This corresponds to having 64 GB for a desktop CPU with 32 threads, like Ryzen 9 9950X.

For the compilation example, I have seen software projects, like Chrome/Chromium and its derivatives, where if you do not have enough memory, proportional to the number of hardware threads, e.g. when you have only 32 GB for a 16 core/32 thread CPU, you must reduce the number of concurrent compilations, e.g. with an appropriate parameter to "make -j", leaving some threads and cores idle, because otherwise you may encounter out-of-memory errors.

There is some overhead per-core, you're right, but imo this reduction in usage is likely from how the kernel allocates available memory, which is being reduced as well. The kernel will keep read caches around longer with more memory, it'll prefer to compress memory instead of swap to disk if it has more, it'll purge/cleanup reclaimable memory less often with more memory, etc. It even scales its internal buffer sizes and vnode tables depending on total memory.

All good things imo, it dynamically makes the most of what is available, at the expense of making it harder to see a true baseline of hard min requirement to operate.

Fun things to check, `vm_stat`

$ vm_stat Mach Virtual Memory Statistics: (page size of 4096 bytes)

Pages free: 230295.

Pages active: 1206857.

Pages inactive: 1206361.

Pages speculative: 31863.

Pages throttled: 0.

Pages wired down: 470093.

Pages purgeable: 18894.

"Translation faults": 21635255.

Pages copy-on-write: 1590349.

Pages zero filled: 11093310.

Pages reactivated: 15580.

Pages purged: 50928.

File-backed pages: 689378.

Anonymous pages: 1755703.

Pages stored in compressor: 0.

Pages occupied by compressor: 0.

Decompressions: 0.

Compressions: 0.

Pageins: 832529.

Pageouts: 225.

Swapins: 0.

Swapouts: 0.

edit: no code fence markdown support or am I doing something wrong?

I got torch to run in a Cirruslabs Tart instance.

I need this too, and looked quite a lot on it a year ago. I haven’t had time to check out the recent developments with Docker Model Runner (vllm-metal) or podman libkrun. Did neither of those work for you?

I don’t assume that macOS virtualization is advanced enough to support memory ballooning, or is that not what you’re referring to?

Edit: I stand corrected!

Try Apple's container CLI. I moved a project of mine from colima+docker to it relatively easily, a couple of weekends ago.

https://github.com/apple/container

Recently got a Mac Mini for local CI purposes (together with Forgejo Actions), took a broad look at the ecosystem and decided to just roll with "build on host" instead. Setting up signing/notarization just looked like an insurmountably task together with isolating it from the host, even with agents. At least the macOS builds are really fast now and the signing/notarization just ~200 lines of Bash...

You can boot regular macOS directly to a root terminal in “Single User Mode”. This was easier on Intel macs of yore but is also possible on M1+

Below content from https://eclecticlight.co/2020/11/28/startup-modes-for-m1-mac...

Launch 1 True Recovery, open Terminal, then run “bputil -a” (without the quotes) to downgrade system security and allow for more boot arguments. You might need to restart after this step.

Then, run [nvram boot-args=”-s”] (without the square brackets). Restart to launch Single User Mode.

Once in Single User Mode, run these commands (in the following order) to mount the root volume group:

1. mount -P 1

2. /usr/libexec/init_data_protection

3. mount -P 2

Future restarts will always launch Single User Mode first. To stop launching Single User Mode, run [nvram boot-args=“”] (without the square brackets).

To restore your system to full security, run “bputil -f” (without the quotes). If you choose to run that command in macOS, prefix “sudo” to the beginning.

"I'd just like to interject for a moment. What you're referring to as macOS, is in fact, macOS/Darwin, or as I've recently taken to calling it, macOS plus Darwin."

"What you're referring to as Darwin, is in fact, Darwin/XNU."

"What you're referring to as XNU, is in fact, BSD/Mach."

I seem to remember it being possible to run macOS-less Darwin several years ago, not sure if that's still possible or if Apple has modified it so much at this point that it's useless without at least some macOS components.

Macbook Neo should run rings around any Intel Air: Geekbench shows it at 250% the score of 2020 Intel Air.

https://browser.geekbench.com/v6/cpu/compare/17022784?baseli...