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Comment by apignotti | Hacker News Reader

Hello HN, author of the post here, happy to answer questions.

How does this compare to https://bellard.org/jslinux/tech.html? https://bellard.org/jslinux/

And jor1k (JavaScript openrisc processor emulator) : well, they emulate processors (x86, openrisc..) in JavaScript while WebVM execute (transpiled?) code in webassembly

Perf. Our JIT is extremely advanced. Of course different workloads will behave differently, but you are welcome to try multiple payloads and see for yourselves.

What constitutes advanced?

So, this is a reimplementation of the Linux ABI and no Linux kernel source is involved, right?

That's correct.

Have you tried compiling Linux as User Mode Linux with emscripten? I imagine something like this https://github.com/nabla-containers/nabla-linux would run on wasm, too?

Well, User Mode Linux would still require an underlying Linux ABI, for example mmap to implement pagination. With sufficient work it might be possible to actually run UM Linux _on top_ of CheerpX / WebVM.

Implementing the Linux ABI ourselves gives us the opportunity of a tighter integration with the Web platform anyway.

Hey dude, I've been screwing around implementing plan9 semantics in a OS like system for the browser (https://github.com/intigos/possimpible). I'm interested in using a x86 emulator inside a webwoker that I'm using for processes so I can run x86 code. How hard is something like this? Can you give me some pointers on how to start working on this? Thanks!

It seems to not work with my eager block settings. It works with a fresh Firefox profile though, so it's not clear what the issue exactly is though. I know for sure that the ext2 is never actually downloaded (0 byte response) and when I try to check anything in DevTools cxcore.wasm triggers a pause on debugger statement, which spikes the CPU.

Any chance there could be a version with all the assets in one thing (say, GitHub Pages)?

Is there support for loopback networking (for IPC)? Is there a way to translate HTTP(S) requests to `fetch` requests? How difficult would it be to port a Go app that uses https://github.com/pion/webrtc to use the browser's native WebRTC?

HTTP request could be intercepted, but due to CORS they would most likely not succeed. I have not studied the WebRTC protocol in detail but it might be possible.

What performance bottlenecks are there that can still be improved?

Right now I see a ~6x slowdown on small-code benchmarks like sieve, but it goes up to 50x or more for large code like GCC. For QEMU it's roughly 1.6x and 2-3x respectively, so it seems like your JIT is slower than QEMU's.

Is this tech a reasonable way for cross-platform emulation, e.g. a x86 VM running on a browser on ARM hardware like the new Apple chips?

In essence, for this approach, would the x86-on-x86 performance hit be similar or very different than the x86-on-ARM performance hit?

The actual host hardware does not matter, neither in terms of support or performance, theoretically. We currently optimize the codegen for Chrome/V8 on x86.

How about the network stack? Is the VM can talk with other VMs from other browsers.

Not in the current implementation, but absolutely possible with WebRTC. We have done something equivalent some time ago: https://medium.com/p/29fbbc62c5ca

Will you open source your code one day and if no, why not?

Impressive stuff! Worth to try to run the OSv unikernel (one of my babies) in it.

Can you run containers in webvm?

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