Hacker News new | ask | show | jobs
by neonsunset 812 days ago
Initial experiment issue: https://github.com/dotnet/runtime/issues/94620

Experiment results write-up: https://github.com/dotnet/runtimelab/blob/e69dda51c7d796b812...

TLDR: The green threads experiment was a failure as it found (expected and obvious) issues that the Java applications are now getting to enjoy, joining their Go colleagues, while also requiring breaking changes and offering few advantages over existing model. It, however, gave inspiration to subsequent re-examination of current async/await implementation and whether it can be improved by moving state machine generation and execution away from IL completely to runtime. It was a massive success as evidenced by preliminary overhead estimations in the results.
1 comments
vips7L 812 days ago
The tl;dr that I got when I read these a few months ago was that C# relies on too much FFI which makes implementing green threads hard and on top of that would require a huge effort to rewrite a lot of stuff to fit the green thread model. Java and Go don’t have these challenges since Go shipped with a huge standard library and Java’s ecosystem is all written in Java since it never had good ffi until recently.
link
neonsunset 812 days ago
Surely you're not claiming that .NET's standard library is not extensive and not written in C#.

If you do, consider giving .NET a try and reading the linked content if you're interested - it might sway your opinion towards more positive outlook :)

link
vips7L 811 days ago
> Surely you're not claiming that .NET's standard library is not extensive and not written in C#.

I’m claiming that MSFT seems to care really about P/Invoke and FFI performance and it was one of the leading reasons for them not to choose green threads. So there has to be something in .NET or C# or win forms or whatever that is influencing the decision.

I’m also claiming that this isn’t a concern for Java. 99.9% of the time you don’t go over FFI and it’s what lead the OpenJdk team to choose virtual threads.

> If you do, consider giving .NET a try

I’d love to, but dealing with async/await is a pain :)

link
neonsunset 811 days ago
You’ve never used it, so how can you know?
link
vips7L 811 days ago
How do you know I've never used it? Do you have a crystal ball?
link