runtimelab VS Introducing .NET Multi-platform App UI (MAUI)

For everyone reading this blog post I caution that the conclusions there are at best creative interpretations of the notes written down here: https://github.com/dotnet/runtimelab/blob/feature/async2-exp...

It is quite literally impossible to draw conclusions on e.g. memory consumption until the work on this, which is underway, makes it into mainline runtime. It's important to understand that the experiment was first and foremost a research to look into modernizing async implementation, and was a massive success. Now once that is proven, the tuned and polished implementation will be made.

Once it is done and makes into a release (it could even be as early as .NET 10), then further review will be possible.

This FAQ is a bit outdated in places, and is not something most users should worry about in practice.

JVM Green Threads here serve predominantly back-end scenarios, where most of the items on the list are not of concern. This list also exists to address bad habits that carried over from before the tasks were introduced, many years ago.

In general, the perceived want of green threads is in part caused by misunderstanding of that one bad article about function coloring. And that one bad article about function coloring also does not talk about the way you do async in C#.

Async/await in C# is just a better model with explicit understanding where a method returns an operation that promises to complete in the future or not, and composting tasks for easy (massive) concurrency is significantly more idiomatic than doing so with green threads or completable futures that existed in Java before these.

Also one change to look for is "Runtime Handled Tasks" project in .NET that will replace Roslyn-generated state machine code with runtime-provided suspension mechanism which will only ever suspend at true suspension points where task's execution actually yields asynchronously. So far numbers show at least 5x decrease in overhead, which is massive and will bring performance of computation heavy async paths in line with sync ones: https://github.com/dotnet/runtimelab/blob/feature/async2-exp...

Async/await is not a tight corner as showcased by a multitude of languages adopting the pattern: Rust, Python, JavaScript and Swift.

In fact, it is a clean abstraction where future progress is possible while retaining the convenience of its concurrency syntax and task composition.

Green threads experiment proved net negative in terms of benefit but its the follow-up work on modernizing the implementation detail was very successful: https://github.com/dotnet/runtime/issues/94620 / https://github.com/dotnet/runtimelab/blob/feature/async2-exp...

It also seems that common practices in Java indicate that properties are not a mistake as showcased by popularity of Lombok and dozens of other libraries to generate builders and property-like methods (or, worse, Java developers having to write them by hand).

There was a "green thread" experiment for dotnet a while ago, here is the conclusion: https://github.com/dotnet/runtimelab/issues/2398

Experiment result 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. 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.

Yeah, it kind of is. There are quite a few of experiments that are conducted to see if they show promise in the prototype form and then are taken further for proper integration if they do.

Unfortunately, object stack allocation was not one of them even though DOTNET_JitObjectStackAllocation configuration knob exists today, enabling it makes zero impact as it almost never kicks in. By the end of the experiment[0], it was concluded that before investing effort in this kind of feature becomes profitable given how a lot of C# code is written, there are many other lower hanging fruits.

To contrast this, in continuation to green threads experiment, a runtime handled tasks experiment[1] which moves async state machine handling from IL emitted by Roslyn to special-cased methods and then handling purely in runtime code has been a massive success and is now being worked on to be integrated in one of the future version of .NET (hopefully 10?)

[0] https://github.com/dotnet/runtime/issues/11192

[1] https://github.com/dotnet/runtimelab/blob/feature/async2-exp...

Unlike these folks from dotnet, which tested directly on ASP for real workload

  https://github.com/dotnet/runtimelab/issues/2398?darkschemeovr=1

[1] https://github.com/dotnet/runtimelab/issues/2398

The only way to avoid it is to not build on top of Java or not adding any features on top of Java.

> To give another example with C#, there has been a lot of recent discussion about finding potential alternatives to their async-await concurrency model. They cite the level of effort it takes to maintain the async await style code and the costs that come from this.

I had a very different take-away. They did PoC with virtual threads and decided it's not worth the switch now and async-await that they have is good enough.

https://github.com/dotnet/runtimelab/issues/2398

> Some of the languages it gets compared too aren't even that old yet.

C# is old enough to drink and Scala just had its 20th birthday this week :)

Unified Codebases: Frameworks like Uno Platform and .NET MAUI enable developers to write once and deploy across web and native platforms.

I am migrating XF app into MAUI and writing a simple Navigation framework because Prism doesn't work well and I didn't use anything advanced anyway. So, I am surfing the code of MAUI to intercept all the back buttons, etc. I haven't found a single mention of apis related to predictive back "RegisterOnBackInvokedCallback", "OnBackInvokedDispatcher", "OnBackPressedDispatcher", "AddCallback", "android:enableOnBackInvokedCallback" Also I don't see any issue on github that would say "Support Android Predictive back". Only one kinda related https://github.com/dotnet/maui/issues/8680

Below issue is still reproducing in Maui .net7.0 version also. #10163

Maui is Open Source, MIT License

https://github.com/dotnet/maui

.NET is Open Source

https://dotnet.microsoft.com/en-us/platform/open-source

I do share your skepticism of Microsoft, but it looks like the economics and cash flow dynamics have changed drastically after the advent of the cloud.

Microsoft is more focused on getting developers onto its ecosystem and help them with open source projects with the hope that they will use its Azure cloud services and bring in the money.

My skepticism is a bit relaxed now and I have no qualms using .NET.

I hope I am not wrong.

It's a bit of a hit and miss as of today. CLI, back-end and natively compiled libraries (think dll/so/dylib or even .lib/.a - you can statically link NAOT binaries into other "unmanaged" code) work best, GUI - requires more work.

Avalonia[0] and MAUI[1] have known working templates with it, but YMMV.

[0] https://github.com/lixinyang123/AvaloniaAOT / https://github.com/AvaloniaUI/Avalonia/ / honorable mention https://github.com/VincentH-Net/CSharpForMarkup

[1] https://github.com/dotnet/maui (try out with just true in csproj - it is known to work e.g. on iOS)

While this is the quite endorsed by the community: https://github.com/dotnet/maui/discussions/339

I think the fundamental issue is that desktop Linux is way too fragmented. Not only just GTK2/3 and Qt but you have GNOME, KDE, XFCE, Cinnamon and then you have X11, Xorg, Wayland...

To be honest, all those craps are why desktop Linux never took off. I'm very safe to say MAUI for Linux will eventually renders components off its own using framebuffer and hardware acceleration APIs such as OpenGL or Vulkan just because of the market fragmentations...

If desktop Linux truly wants to get the attention, it will need to unify. Fixing dependency hell using Flatpak is the right direction.

There is an existing old fork of MAUI for Linux that uses GTK: https://github.com/jsuarezruiz/maui-linux

First I came across this Github issue: https://github.com/dotnet/maui/issues/9687 - According to this issue, this is a known bug for MAUI iOS, but it works OK for MAUI Android. As I said, I target Android only and I have the exact same issue. It's apparantly fixed with some of the latest versions for MAUI but the problem still occurs to me even with MAUI version:

I saw this and tried to imitate (ofc my lack of experience wouldn't allow me to do it in the exact way). Already found some documentation that allowed to understand better. Thanks for the insigh.