The CoreCLR should easily perform twice as good as Mono in many cases.
https://docs.unity3d.com/Manual/Mono.html
Seems so. In fact, not just Mono but their own fork of Mono.
As a C#/.Net developer I'm satisfied with the C# and .Net support in Unity. The pain points are elsewhere.
Not sure if this is what you mean but one huge pain point for almost every dev is that code changes necessitate a project reload, which, even with domain reload can be extremely slow and gets worse the larger the project becomes.... which is why I'm extremely exuberant about the new hot-reload plugins which allow editing code while a project is running and changes will be patched in real time! For me it's comparable to when SSDs first came out, finally we were able to ditch slow spinning rust. I've been using it for a couple days now and I've probably already saved a few hours.
I've been using HotReload.net which is free for Unity Personal Edition but there's also an asset on the store for ~40€ but i haven't looked at it yet.
I also wouldn't call Unity's Mono 'heavily optimized' because they definitely trail behind standard Mono. Unity doesn't even support Mono's generational garbage collector but it has been the default in Mono since 2016.
And I think .NET6 supports mobile now?
[disclosure: I work on Mono at Microsoft.]
[1] https://forum.unity.com/threads/performance-optimizations-fo... [2] https://forum.unity.com/threads/expected-performance-of-new-...
I recently learned that mono works kinda like an interpreted language. This makes sense I think because the internals of unity run C++ code; the C# code is just an interface into the C++ parts of the engine.
I haven't done a deep dive into .net ecosystem ever. I probably should at some point. Since I only work in unity and since unity doesn't really play well with the .net ecosystem (e.g. one installs nuget pkgs by downloading the nuget file directly from the website, renaming the file extension to "zip" to then extract the files, and then copy DLLs into an "editor" folder in your project files), I haven't had as much of an incentive.
Today I work as a cloud engineer largely focusing on infrastructure set up, and writing GO/bash code for various bits of automation. Before I worked in scala/Java, and before that node.
Note in this comment I might be slightly imprecise with the use of naming since the specification, standard library, runtime can be separate projects each with its own name. But often multiple of those parts are made by same people so it can be a bit confusing especially with the way Microsoft names them with various capitalization.
Mono started as open source implementation of .Net and means to run C# on Linux when the Microsoft implementation of .Net was fully closed source and worked only on Windows. At that point it made sense for Unity to use whatever open source implementation of .Net they had access to which was mono. Years have passed and a lot of things have changed. At some point Microsoft bought Xamarin(the company that is main contributor/maintainer for mono project).
On the other side coreCLR is latest implementation of .Net from Microsoft. Unlike earlier versions of .Net from Microsoft it is open source and compatible with Linux and macOS.
As with many languages one of the implementations (the one made by inventor in this case Microsoft) is the leader, while others are playing catch up both in terms of new language feature support and also quality and tooling. Such situation is hard to avoid because developers of one implementation are making whatever they want while being sponsored by big company. While the others are trying to implement something that's more or less compatible with leader while having much smaller budget.
In the early days mono at least had the benefits of being open source and crossplatform compatible. Now they have lost this advantage. Even worse, the main contributor of mono is owned by Microsoft so there is high chance that they will slowly kill it in favor of their own implementation. Since the coreCLR is the primary implementation made by Microsoft it will more likely have much better integration and compatiblity with all the developer tooling made by Microsoft (Visual Studio, debugger) , better compatiblity with various third party .Net libraries, better support for new language features.
[disclosure: I work on Mono at Microsoft.]
Wow this is huge! Seems like Unity is lagging behind and their journey for CoreCLR just stared.