News Announcing .NET 6 Preview 3

[FireWind]

Announcing .NET 6 Preview 3
April 8th, 2021

Today, we are delighted to release .NET 6 Preview 3. This release is dedicated almost entirely to low-level performance features. These are the types of improvements that many folks don’t necessarily always fully appreciate, but they help a lot for many apps. Most of these improvements apply to the CLR type system directly, either making it function faster or better interplay with modern CPUs (think “hardware accelerate the type system”). In the last few years, there have been a few key performance trends with .NET, including: using structs more liberally in libraries, and moving runtime code to C#. Both of trends are visible (directly or indirectly) in these changes. It also demonstrates continued efforts on a focused set of performance strategies.

You will notice that two of these performance changes came Для просмотра ссылки Войди или Зарегистрируйся. He’s well known for word play on his Для просмотра ссылки Войди или Зарегистрируйся. In the spirit of April 1st (recently past), perhaps we can virtually rename this release to .NET 6 Preview B3n. Thanks B3n!

You’ll also see performance contributions from Для просмотра ссылки Войди или Зарегистрируйся and Для просмотра ссылки Войди или Зарегистрируйся. Thanks!

You can Для просмотра ссылки Войди или Зарегистрируйся, for Windows, macOS, and Linux.

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See the Для просмотра ссылки Войди или Зарегистрируйся for more detail on what’s new for web technology. For EF Core, Для просмотра ссылки Войди или Зарегистрируйся includes several bug fixes and ongoing improvements to infrastructure to support upcoming features including compiled models and temporal tables

.NET 6 has been tested with Visual Studio 16.10 Preview 1 and Visual Studio for Mac 8.9. We recommend you use those builds if you want to try .NET 6.

For Linux users: .NET SDK 6 Preview 3 resolves an issue where Для просмотра ссылки Войди или Зарегистрируйся due to expired NuGet certificates and unfortunate interactions with changes made to root certificates stores on Linux, carried by ca-certificates and nss packages. Please update your Для просмотра ссылки Войди или Зарегистрируйся and .NET 6 SDK deployments on Linux, ASAP.

Support​

.NET 6 will be will be released in November 2021, and will be supported for three years, as a Для просмотра ссылки Войди или Зарегистрируйся. The Для просмотра ссылки Войди или Зарегистрируйся has been significantly expanded.

The additions are:

• Android.
• iOS.
• Mac and Mac Catalyst, for x64 and Apple Silicon (AKA “M1”).
• Windows Arm64 (specifically Windows Desktop).

.NET 6 Debian container images are based on Debian 11 (“bullseye”), which is Для просмотра ссылки Войди или Зарегистрируйся.

Libraries​

The following APIs and improvements have been added to the .NET libraries.

Faster handling of structs as Dictionary values​

A new unsafe api — Для просмотра ссылки Войди или Зарегистрируйся — has been added that makes updating struct values in Dictionaries faster. The new API is intended for high performance scenarios, not for general purpose use. It returns a ref to the struct value which can then be updated in place with typical techniques.

Prior to this change, updating struct dictionary values can be expensive for high-performance scenarios, requiring a dictionary lookup and a copy to stack of the struct; then after changing the struct, it needs to be assigned to the dictionary key again resulting in another look up and copy operation. This improvement reduces the key hashing to 1 (from 2) and removes all the struct copy operations.

Example:

ref MyStruct value = CollectionsMarshal.GetValueRef(dictionary, key);
// Returns Unsafe.NullRef<TValue>() if it doesn't exist; check using Unsafe.IsNullRef(ref value)
if (!Unsafe.IsNullRef(ref value))
{
    // Mutate in-place
    value.MyInt++;
}

Credit to Для просмотра ссылки Войди или Зарегистрируйся.

Faster interface checking and casting​

Для просмотра ссылки Войди или Зарегистрируйся by 16% – 38%. This improvement is particularly useful for C#’s pattern matching to and between interfaces.

Method	Implementation	Mean​	Version	Ratio​	Improvement​
IsInterface1	Interfaces1	2.166 ns​	.NET 6 Preview 2	1.000​	​
IsInterface1	Interfaces1	1.629 ns​	.NET 6 Preview 3	0.752​	x1.3​
IsNotImplemented	Interfaces1	2.166 ns​	.NET 6 Preview 2	1.000​	​
IsNotImplemented	Interfaces1	1.950 ns​	.NET 6 Preview 3	0.900​	x1.1​
		​		​	​
IsInterface1	Interfaces6	2.155 ns​	.NET 6 Preview 2	1.000​	​
IsInterface1	Interfaces6	1.936 ns​	.NET 6 Preview 3	0.898​	x1.1​
IsInterface2	Interfaces6	2.161 ns​	.NET 6 Preview 2	1.000​	​
IsInterface2	Interfaces6	1.908 ns​	.NET 6 Preview 3	0.883​	x1.1​
IsInterface3	Interfaces6	2.188 ns​	.NET 6 Preview 2	1.000​	​
IsInterface3	Interfaces6	1.672 ns​	.NET 6 Preview 3	0.764​	x1.3​
IsInterface4	Interfaces6	2.346 ns​	.NET 6 Preview 2	1.000​	​
IsInterface4	Interfaces6	1.965 ns​	.NET 6 Preview 3	0.838​	x1.2​
IsInterface5	Interfaces6	3.122 ns​	.NET 6 Preview 2	1.000​	​
IsInterface5	Interfaces6	2.173 ns​	.NET 6 Preview 3	0.696​	x1.4​
IsInterface6	Interfaces6	3.472 ns​	.NET 6 Preview 2	1.000​	​
IsInterface6	Interfaces6	2.687 ns​	.NET 6 Preview 3	0.774​	x1.3​
IsNotImplemented	Interfaces6	3.644 ns​	.NET 6 Preview 2	1.000​	​
IsNotImplemented	Interfaces6	3.071 ns​	.NET 6 Preview 3	0.843​	x1.2​

One of the biggest advantages of moving parts of the .NET runtime from C++ to managed C# is that it Для просмотра ссылки Войди или Зарегистрируйся. This includes interface casting, which was moved to C# as an early .NET 6 change. Many more people in the .NET ecosystem are literate in C# than C++ (and the runtime isn’t even regular C++). Just being able to read some of the code that composes the runtime is a major step to developing confidence in contributing, in its various forms.

Credit to Для просмотра ссылки Войди или Зарегистрируйся.

Runtime: Codegen​

The following changes improve code generation in RyuJIT, either making the process more efficient or the resulting code faster to run. A recent post on Для просмотра ссылки Войди или Зарегистрируйся does a great job of demonstrating the level of consideration and detail that is required for optimal performance.

Optimizations:​

• Для просмотра ссылки Войди или Зарегистрируйся Credit: Для просмотра ссылки Войди или Зарегистрируйся
• Для просмотра ссылки Войди или Зарегистрируйся Credit Для просмотра ссылки Войди или Зарегистрируйся
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Dynamic PGO​

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Keep structs in register​

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Completed .NET 6 EH Write Thru​

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[FireWind]

Tools: Initial .NET Hot Reload support now available for web apps​

Early support for .NET Hot Reload is now available for ASP.NET Core & Blazor projects using dotnet watch. .NET Hot Reload applies code changes to your running app without restarting it and without losing any app state. Code changes that cannot be applied to the running app can still be applied by rebuilding and restarting the app.

This is just the first step in our more comprehensive plan to bring this technology to all .NET developers including desktop (WPF, WinUI, WinForms), cross-platform client scenarios in .NET MAUI, and more. .NET Hot Reload will be supported with these additional platforms in future preview releases of .NET 6. In addition, we will also make .NET Hot Reload available as an integrated experience in future Visual Studio releases.

For more details on trying out hot reload with web app projects, see Для просмотра ссылки Войди или Зарегистрируйся

Closing​

We’re now about half way through the .NET 6 release, at least in terms of feature development. You can read about other features that have been added, in the Для просмотра ссылки Войди или Зарегистрируйся and Для просмотра ссылки Войди или Зарегистрируйся releases. We expect some larger features to land in the next few previews before we start into focusing on quality in the release candidate builds.

I started the post raising visibility on some great community contributions. Some community folks are using the Для просмотра ссылки Войди или Зарегистрируйся program to support spending more of their time on contributing to .NET. That’s great. Для просмотра ссылки Войди или Зарегистрируйся. I encourage you to consider supporting community developers improving .NET, perhaps focused on a part of the product you depend on significantly. Its a good opportunity to invest in your supply chain.